EP0693122A1 - Glutamylcysteine synthetase light subunit - Google Patents

Abstract

The nucleotide cDNA sequence for the light subunit of gamma glutamylcysteine synthetase, and the amino acid sequence for this subunit, are disclosed.

Description

GLUTAMYLCYSTEINE SYNTHETASE LIGHT SUBUNIT

This is a continuation-in-part of United States Patent Application 765,211 , filed September 25th 1991 .

Partial funding for the making of the invention described herein was provided by the United States National Institutes of Health under Grant No. 4R37 DK12034. Accordingly, the United States Government has certain statutory rights to the claimed invention under 35 USC 200 et seq.

Glutathione is a tripeptide thiol (L-gamma-glutamyl-L- cysteinylglycine) present in animal tissues, plants, and microorganisms. It is found intracellularly in high (0.1 to 10 mM) millimolar concentrations and is thus the most prevalent cellular thiol and the most abundant low molecular weight peptide typically found in mammals. The two characteristic structural features of glutathione - the gamma-glutamyl linkage and a sulfhydryl group - promote its intracellular stability and are intimately associated with its multiple biochemical functions.

Glutathione protects cells from the toxic effects of reactive oxygen compounds and is an important component of the system that uses reduced pyridine nucleotide to provide the cell with its reducing properties which promote, for example, intracellular formation of cysteine and the thiol forms of proteins; glutathione functions in catalysis, metabolism, and transport; it participates in reactions involving the synthesis of proteins and nucleic acids and in those that detoxify free radicals and peroxides; it forms conjugates with a variety of compounds of endogenous and exogenous origin and is a cofactor for various enzymes.

A generalized outline of the biochemistry of glutathione is depicted in the Glutathione cycle schematic appearing in United

States Patent Application 765,211 , and is incorporated in toto herein.

Glutathione functions as a co-enzyme for formaldehyde dehydrogenase, maleylacetoacetate isomerase, glyoxalase, prostaglandin endoperoxidase isomerases, and dichlorodiphenyltrichloroethane dehydrochlorinase and similar enzymes. In the glyoxalase reaction, the hemimercaptal formed nonenzymatically by reaction of methylglyoxal and glutathione (GSH) is converted by glyoxalase I to S-lactyl-Glutathione, which is split by glyoxalase II to D-lactate and Glutathione. In the formaldehyde dehydrogenase reaction, S-formyl Glutathione is formed (Glutathione + HCHO + NAD+) and hydrolyzed to formate and Glutathione. Within cells, GSH is synthesized by the actions of gamma- glutamylcysteine synthetase and Glutathione synthetase as shown in the following reactions. Gamma-glutamylcysteine catalyzes the first of these reactions and is the rate limiting reaction in Glutathione synthesis. L-glutamate + L-cysteine + ATP => L-gamma-glutamyl-L-cysleine + ADP + Pi

L-gamma-glutamyl-L-cysteine + glycine + ATP => Glutathione +ADP = Pi

Humans who lack either of the two enzymes needed for glutathione synthesis experience a number of serious physical symptoms including mental retardation, hemolytic anemia, and paralyses.

The activity of the holoenzyme is feedback inhibited by GSH [see J. Biol. Chem. 250:1422 (1975)]. Such inhibition, which provides a mechanism that regulates the GSH level in various tissues, is accompanied by reduction of the enzyme and by competitive inhibition by GSH with respect to glutamate [see J.

Biol. Chem (1993)].

Highly purified preparations of gamma-glutamylcysteine synthetase have been isolated from several sources including rat erythrocytes, bacteria, and rat kidney. The enzyme purified from rat kidney (Mr approximately 104,000) is homogeneous on gel electrophoresis and dissociates under denaturing conditions to yield two nonidentical subunits - a heavy subunit of Mr -73,000 and a light subunit of Mr -27,700. The holoenzyme can also be dissociated into two subunits under nondenaturing conditions. The isolated heavy subunit is catalytically active and it is feedback inhibited by GSH. These findings led to cloning and sequencing of the cDNA coding for the heavy subunit described in United States Patent Application 765,211. This open frame oligonucleotide sequence of the heavy subunit is:

ATG GGG CTG CTG TCC CAA GGC TCG CCA CTG AGC TGG GAA 39

GAG ACC CAG CGC CAC GCC GAC CAC GTG CGG AGA CAC GGC 78

ATC CTC CAG TTC CTG CAC ATC TAC CAC GCA GTC AAG GAC 117

CGG CAC AAG GAC GTG CTC AAG TGG GGT GAC GAG GTG GAG 156 TAC ATG TTG GTG TCC TTT GAT CAT GAA AAT AGG AAA GTC 195

CAG TTG TTA CTG AAT GGC GGC GAT GTT CTT GAA ACT CTG 234

CAA GAG AAG GGG GAG AGG ACA AAC CCC AAC CAC CCA ACC 273

CTC TGG AGA CCA GAG TAT GGG AGT TAC ATG ATT GAA GGG 312

ACA CCT GGC CAG CCG TAC GGA GGA ACG ATG TCC GAG TTC 351 AAC ACA GTG GAG GAC AAC ATG AGG AAA CGC CGG AAG GAG 390

GCT ACT TCT GTA TTA GGA GAA CAT CAG GCT CTT TCG ACG 429

ATA ACT TCA TTT CCC AGG CTA GGC TGC CCT GGA TTC ACA 468

CTG CCA GAG CAC AGA CCC AAC CCA GAG GAA GGA GGT GCA 507

TCT AAG TCC CTC TTC TTT CCA GAC GAA GCC ATA AAC AAG 546 CAC CCC CGC TTT GGT ACT CTA ACA AGA AAC ATC CGG CAT 585

CGG AGA GGA GAA AAG GTT GTC ATC AAT GTG CCA ATA TTC 624

AAG GAC AAG AAC ACA CCA TCT CCG TTT GTA GAA ACA TTT 663

CCT GAG GAT GAG GAG GCA TCA AAG GCC TCT AAG CCA GAC 702

CAC ATC TAC ATG GAT GCC ATG GGA TTT GGG ATG GGC AAC 741 TGC TGT CTT CAG GTG ACA TTC CAA GCC TGC AGT ATA TCT 780

GAG GCA AGA TAC CTT TAT GAC CAG TTG GCC ACT ATC TGC 819

CCA ATT GTT ATG GCT TTG AGT GCT GCA TCG CCA TTT TAC 858

CGA GGC TAC GTG TCA GAC ATT GAT TGT CGC TCG GGA GTG 897

ATT TCT GCA TCT GTA GAT GAT AGA ACA CGG GAG GAG AGA 936 GGA CTG GAG CCC CTG AAG AAC AAT CGC TTT AAA ATC AGT 975

AAG TCT CGG TAT GAC TCA ATA GAT AGC TAC CTG TCC AAG 1014 TGT GGA GAG AAG TAC AAT GAC ATC GAC CTG ACC ATC GAC 1053 ACG GAG ATC TAC GAG CAG CTC TAA GAG GAA GGC ATC GAT 1092 CAC CTT CTG GCA CAG CAG GTT GCT CAT CTC TTT ATT AGA 1131 GAC CCA CTG ACC CTT TTT GAA GAG AAA ATT CAT CTG GAT 1170 GAT GCC AAC GAG TCT GAC CAT TTT GAG AAT ATT CAG TCC 1209 ACA AAC TGG CAG ACA ATG AGG TTT AAG CCT CCT CCT CCA 1248 AAC TCA GAT ATT GGA TGG AGA GTA GAG TTC CGA CCA ATG 1287 GAG GTA CAG TTG ACA GAC TTT GAG AAC TCT GCC TAT GTG 1326 GTA TTT GTG GTA CTG CTG ACC AGG GTG ATC CTC TCA TAC 1365 AAA CTA GAC TTC CTC ATT CCA CTG TCC AAG GTT GAC GAG 1404 AAC ATG AAA GTG GCA CAG GAG CGA GAT GCC GTC TTA CAG 1443 GGG ATG TTT TAT TTC AGG AAA GAC ATT TGC AAA GGT GGC 1482 AAC GCC GTG GTG GAT GGG TGT AGC AAG GCC CAG ACC AGC 1521 TCC GAG CCA TCT GCA GAG GAG TAC ACG CTC ATG AGC ATA 1560 GAC ACC ATC ATC AAT GGG AAG GAA GGC GTG TTT CCT GGA 1599 CTC ATC CCC ATT CTG AAC TCC TAC CTT GAA AAC ATG GAA 1638 GTC GAC GTG GAC ACC CGA TGC AGT ATT CTG AAC TAC CTG 1677 AAG CTA ATT AAG AAG AGA GCA TCT GGA GAA CTA ATG ACT 1716

GTT GCC AGG TGG ATG AGA GAG TTT ATT GCA AAC CAT CCT 1755 GAC TAC AAG CAA GAC AGT GTA ATA ACT GAT GAG ATC AAC 1794 TAT AGC CTC ATT TTG AAA TGC AAT CAA ATT GCA AAT GAA 1833 TTG TGT GAA TGT CCA GAG TTA CTT GGA TCA GGC TTT AGA 1872 AAA GCG AAG TAC AGT GGA GGT AAA AGC GAC CCT TCA GAC 1911

TAG 1914

This open reading frame translates into the peptide:

Mat Gly Leu Leu Ser Gin Gly Ser Pro Leu Ser Trp Glu Glu Thr

5 10 15 Gin Arg His Ala Asp His Val Arg Arg His Gly He Leu Gin Phe

20 25 30

Leu His He Tyr His Ala Val Lys Asp Arg His Lys Asp Val Leu

35 40 45

Lys Trp Gly Asp Glu Val Glu Tyr Met Leu Val Ser Phe Asp His 50 55 60

Glu Asn Arg Lys Val Gin Leu Leu Leu Asn Gly Gly Asp Val Leu

65 70 75

Glu Thr Leu Gin Glu Lys Gly Glu Arg Thr Asn Pro Asn His Pro

80 85 90 Thr Leu Trp Arg Pro Glu Tyr Gly Ser Tyr Mat He Glu Gly Thr

95 100 105 Pro Gly Gin Pro Tyr Gly Gly Thr Mat Ser Glu Phe Asn Thr Val

110 115 120

Glu Asp Asn Met Arg Lys Arg Arg Lys Glu Ala Thr Ser Val Leu

125 130 135 Gly Glu His Gin Ala Leu Cys Thr He Thr Ser Phe Pro Arg Leu

140 145 150

Gly Cys Pro Gly Phe Thr Leu Pro Glu His Arg Pro Asn Pro Glu

155 160 165

Glu Gly Gly Ala Ser Lys Ser Leu Phe Phe Pro Asp Glu Ala He 170 175 180

Asn Lys His Pro Arg Phe Gly Thr Leu Thr Arg Asn He Arg His

185 190 195

Arg Arg Gly Glu Lys Val Val He Asn Val Pro He Phe Lys Asp

200 205 210 Lys Asn Thr Pro Ser Pro Phe Val Glu Thr Phe Pro Glu Asp Glu

215 220 225

Glu Ala Ser Lys Ala Ser Lys Pro Asp His He Tyr Met Asp Ala

230 235 240

Met Gly Phe Gly Mat Gly Asn Cys Cys Leu Gin Val Thr Phe Gin 245 250 255

Ala Cys Ser He Ser Glu Ala Arg Tyr Leu Tyr Asp Gin Leu Ala

260 265 270

Thr He Cys Pro He Val Mat Ala Leu Ser Ala Ala Ser Pro Phe

275 280 285 Tyr Arg Gly Tyr Val Ser Asp He Asp Cys Arg Trp Gly Val He

290 295 300

Ser Ala Ser Val Asp Asp Arg Thr Arg Glu Glu Arg Gly Leu Glu

305 310 315

Pro Leu Lys Asn Asn Arg Phe Lys He Ser Lys Ser Arg Tyr Asp 320 325 330

Ser He Asp Ser Tyr Leu Ser Lys Cys Gly Glu Lys Tyr Asn Asp

335 340 345

He Asp Leu Thr He Asp Thr Glu He Tyr Glu Gin Leu Leu Glu

350 355 360 Glu Gly He Asp His Leu Leu Ala Gin His Val Ala His Leu Phe

365 370 375

He Arg Asp Pro Leu Thr Leu Phe Glu Glu Lys He His Leu Asp

380 385 390

Asp Ala Asn Glu Ser Asp His Phe Glu Asn He Gin Ser Thr Asn 395 400 405 Trp Gin Thr Mat Arg Phe Lys Pro Pro Pro Pro Asn Ser Asp He

410 415 420

Gly Trp Arg Val Glu Phe Arg Pro Mat Glu Val Gin Leu Thr Asp

425 430 435 Phe Glu Asn Ser Ala Tyr Val Val Phe Val Val Leu Leu Thr Arg

440 445 450

Val He Leu Ser Tyr Lys Leu Asp Phe Leu He Pro Leu Ser Lys

455 460 465

Val Asp Glu Asn Mat Lys Val Ala Gin Glu Arg Asp Ala Val Leu 470 475 480

Gin Gly Mat Phe Tyr Phe Arg Lys Asp He Cys Lys Gly Gly Asn

485 490 495

Ala Val Val Asp Gly Cys Ser Lys Ala Gin Thr Ser Ser Glu Pro

500 505 510 Ser Ala Glu Glu Tyr Thr Leu Mat Ser He Asp Thr He He Asn

515 520 525

Gly Lys Glu Gly Val Phe Pro Gly Leu He Pro He Leu Asn Ser

530 535 540

Tyr Leu Glu Asn Mat Glu Val Asp Val Asp Thr Arg Cys Ser He 545 550 555

Leu Asn Tyr Leu Lys Leu He Lys Lys Arg Ala Ser Gly Glu Leu

560 565 570

Mat Thr Val Ala Arg Trp Met Arg Glu Phe He Ala Asn His Pro

575 580 585 Asp Tyr Lys Gin Asp Ser Val He Thr Asp Glu He Asn Tyr Ser

590 595 600

Leu He Leu Lys Cys Asn Gin He Ala Asn Glu Leu Cys Glu Cys

605 610 615

Pro Glu Leu Leu Gly Ser Gly Phe Arg Lys Ala Lys Tyr Ser Gly 620 625 630

Gly Lys Ser Asp Pro Ser Asp

635

The recombinant heavy subunit obtained by expression of the cDNA in E. coli (as well as the heavy subunit isolated from the isolated holoenzyme) exhibits a much higher K_m value for glutamate and a greater sensitivity to feedback inhibition by GSH than the holoenzyme. These results suggested to us that the light subunit, although not enzymatically active by itself, may be essential for the enzyme to maintain high affinity for glutamate and appropriate sensitivity to feedback inhibition by GSH. One aspect of the present invention is to describe the isolation and sequencing of the cDNA coding for the light subunit of γ- glutamylcysteine synthetase.

Another aspect of the present invention is to describe the amino acid sequence of the light subunit of γ- glutamylcysteine synthetase.

Another aspect of the present invention is to describe the cDNA nucleotide sequence for the expression of the light subunit of γ- glutamylcysteine synthetase. The light subunit of γ- glutamylcysteine synthetase cDNA according to the present invention has been expressed in E. coli, and the catalytic properties of the reconstituted recombinant holoenzyme obtained by co-expression of the light and heavy subunits, and by mixing the separately expressed subunits have been examined.

These and other aspects and findings of the present invention, including elucidation of the nucleotide and amino acid sequences of the light subunit of gamma-glutamylcysteine synthetase will be understood more fully by reference to the following examples, figures, and detailed description.

In the figures,

Figure 1 represents the light subunit expression plasmid, pRGCSL, according to the present invention;

Figure 2 represents the co-expression plasmid, pRGCSHL, according to the present invention;

Figure 3 represents the sequencing strategy for Clones 71 and 62 according to the present invention;

Figure 4 represents a tracing showing 2 peaks of the separated light and heavy subunits according to the present invention.

EXAMPLE I Isolation of antibodies to rat kidney γ-GCS light subunit was conducted as follows: Rabbit antiserum to the rat holoenzyme [see J. Biol. Chem. 265:1588 (1990)] (5 ml) was applied to a Sepharose 4B (Pharmacia) column containing the recombinant heavy subunit coupled to Sepharose (1 ml) a flow rate of 15 ml/hr; the effluent was recycled through the column for 2 hr. After washing with PBS (10 ml), the light subunit antibodies were eluted from the column with 0.1 M glycine (pH 2.5). Fractions (2 ml) were collected into tubes containing 0.1 ml of 1 M sodium phosphate (pH 8.0). The specificity of the purified antibody was examined by Western blot analysis, and upon examination it showed a band that reacted with antibody at a molecular weight of approximately 30,000. This antibody so produced was used further in the present invention to screen the cDNA library.

EXAMPLE II Isolation of the rat kidney γGCS light subunit according to the present invention was conducted as follows:

Purified rat kidney γ-glutamylcysteine synthetase (1 mg, 10 nmole) [see Methods in Enzymology 113:379 (1985)] was dissolved in 0.5 ml of Tris-HCI buffer (0.5 Ml; pH 8.5) containing 6 M guanidinium-HCI and 2 mM EDTA. After bubbling the protein solution with nitrogen gas to avoid oxidation by air, dithiothreitol (1.2 mg, 8 μmole) was added and the reaction mixture was incubated at 55° C for 4 hr. The solution was then cooled to room temperature and reacted with iodoacetic acid (3 mg, 16 μmole) for 20 min. The reduced and carboxymethylated protein was applied to a C-4 reverse phase HPLC column (4.2 x 250 mm) equilibrated with 70% solvent A (0.1% trifluoroacetic acid (aqueous) and 30% solvent B (95% acetonitrile, 0.1% trifluoroacetic acid (aqueous). The subunits were separated by a linear gradient of 30 to 70% solvent B, over 40 min, at a flow rate of 1 ml per min and monitored spectrophotometrically at 215 nm.

As described, the reduced and carboxymethylated holoenzyme were applied to a HPLC C-4 reverse phase column which resulted in two separate protein peaks being eluted from the column (Figure 4). Peaks 1 and 2 were identified by SDS gel electrophoresis as the light subunit and the heavy subunit, respectively: The purified light subunit was subjected to cleavage with trypsin as described in the following example.

EXAMPLE III Peptide sequence analysis of rat kidney γGCS light subunit was conducted as follows:

The purified light subunit (0.2 mg) was dissolved in 0.1 ml of Tris-HCI buffer (50 mM; pH 8.0) and reacted with trypsin (6 ng) at 37° C for 16 hr. The peptides formed were separated by HPLC using a C-18 reverse phase column (4.2 x 250 mm); a 0% to 70% linear gradient was used, over 70 min, between 0.1% trifluoroacetic acid and 0.1 % trifluoroacetic acid containing 95% acetonitrile at a flow rate of 1 ml per min. Automated Edman degradation was carried out with a gas-phase sequencer (Applied Biosystems) equipped with an on-line Phenylthiohydantoin (PTH) amino acid analyzer.

As described above, the peptides according to the present invention were separated by a HPLC C-18 reverse column, and the sequence of two apparently homogeneous peptides were obtained by automatic Edman degradation method. The amino acid sequence of the peptides obtained from the light subunit of γ- glutamylcysteine synthetase are given below: Peptide I :

Glu Leu Leu Ser Glu Ala Ser Phe Gin Glu Ala Leu Gin Glu Ser

5 10 15

He Pro Asp He Glu Ala Gin Glu

20 Peptide II:

Ser Leu Glu His Leu Gin Pro Tyr Xaa Glu Glu Leu Glu Asn Leu

5 10 15

Val Gin Ser An oligonucleotide probe was designed and synthesized corresponding to the sequence deduced from peptide I. The probe is a mixture of 32 different 20-mer oligonucleotides corresponding to all codons combination derived from peptide I, above. The letter I in the sequence below represents deoxyinosine, and has been substituted at the wobble positions in two of the codons.

Peptide I Phe Gin Glu Ala Leu Gin Glu rriRNA UUU CAA GAA GCU CUU CAA GAA C G G C U C G G

A A G G

Probe TTT CAA GAA GCI CTT CAA GA

C G G T G Dete-αnined sequence TTC CAG GAA GCT CTT CAA GA

EXAMPLE IV Isolation of the cDNA clones for the light subunit of rat kidney γGCS was carried out as follows: A rat kidney cDNA expression library (Clontech), having an average insert size of 1.1 kb (range from 0.6 to 3.8 kb) and 1.2 x 1 θ6 independent clones in vector λgtll, was immunoscreened as described by Sambrook [see J. Sambrook, E.f. Fritsch and T. Maniatis, "Molecular Cloning, a Laboratory Manual" Cold Spring Harbor Laboratory Press (1989)] using antibody, prepared in accordance with Example I, to the light subunit. An overnight culture of E. coli Y1090r- (Clontech) grown in LB medium containing 0.2% maltose and 10 mM MgS04, was divided into ten 0.1 ml portions. Each tube containing a portion was infected with 5 x 10⁴ plaque formation units (pfu) of the bacteriophage λgtll expression library (Clontech) at 37° C for 15 min. After mixing with 7 ml of top agarose (LB medium containing 0.75% agarose), the infected bacteria were poured onto 10 LB agar plates (150 x 35 mm) containing ampicillin (100 μg/ml) and incubated at 42° C for 3.5 hr. The plates were then covered with isopropylthiogalactoside (IPTG) (10 mM)-treated nitrocellulose filters, and incubated at 37° C for 4 hrs. The filters were carefully peeled off the plates and rinsed with TNT Buffer (10 mM Tris-HCI (pH 8.0), 150 mM NaCI, and 0.05% Tween 20). The plates were then covered with second set of nitrocellulose filters and incubated at 37° C for an additional 6 hrs.

The two sets of nitrocellulose filters were treated with blocking buffer (TNT containing 5% nonfat dry milk) for 1 hr followed by the same buffer containing diluted (1 :500) antibody to the light subunit for an additional 4 hrs. After washing with

TNT Buffer three times, the filters were treated with diluted (1 :5000) peroxidase-linked goat anti-rabbit IgG antibody for 1 hr. After washing (five times), the antigen-antibody complex was detected by incubating the filters with Tris-HCI buffer (10 mM; pH 7.5) containing 0.018% H2O2 and 0.06% 3,3'-diaminobenzidine for 5 min. Positive plaques that appeared on both sets of the nitrocellulose filters were picked, grown and re-screened with the same antibody.

As described, a rat kidney cDNA λgtll expression library, containing the cDNAs in the phage EcoRI site, was screened with antibody to the light subunit. From about 5 x 10⁵ phages, 38 positive clones were obtained. The expressed fusion protein from 21 of those clones reacted with the antibody when tested by western blot analysis. The phage DNA from those clones were isolated, and the two clones (numbered 62 and 71 ) with the largest inserts were chosen for further analysis. When digested with EcoRI followed by agarose gel electrophoresis, two DNA bands that represent the insert cDNAs were obtained from each of the two clones. Thus, clone 62 was found to contain a 1 kb and a 0.4 kb band, while a 0.7 and a 0.4 kb bands were found contained in clone 71. These results indicate that the cDNAs in these two clones most likely contains similar DNA sequences. Southern blot analysis showed that the 1 kb band from clone 62 and the 0.7 kb band from clone 71 hybridized with the oligonucleotide probe described above. It was the #1.0, 0.7, and 0.4 kb DNAs that were subcloned into the ECoRI site of phagmid pBluescript KS-(+) for sequence analysis.

EXAMPLE V Purification of recombinant bacteriophage λDNA was conducted as follows:

Recombinant λphage particles (1 x 10⁶ pfu), obtained from the positive clones, were separately incubated with E. coli Y1090r- (1 x 10⁸ cells) at 37° C for 20 min. The infected cells were inoculated in 50 ml of prewarmed LB medium until the cells lysed (about 6-8 hrs). After removal of cellular debris by centrifugation (3000 x g for 5 min), the λphage was precipitated by adding NaCI (2.9 g) and polyethylene glycol (MW 8000; 5 g) to the medium. After standing on ice for 2 hrs, the precipitated phage particles were recovered by centrifugation (5000 x g for 10 min). The pellet was resuspended with 4 ml of TM buffer (50 mM Tris-HCI (pH 7.5) and 10 mM MgSθ4); and the excess PEG8000 was removed by extracting the solution with 4 ml of chloroform. The aqueous layer was passed through a DE52 column (4 ml) pre- equilibrated with TM buffer. The column was washed with 3 ml of TM and the effluent (7 ml) was collected. Isopropanol (7 ml) and NaCI (400 #1 ; 4 M) were added to the effluent and the solution was placed on ice for 1 hr. The phage was precipitated by centrifugation (8000 x g for 10 min) and resuspended with 500 μl TE buffer (10 mM Tris-HCI; pH 8.0, and 1 mM EDTA). The phage solution was extracted with 500 μl phenol (saturated with Tris- HCI buffer, pH 8.0), followed by extraction with the same volume of phenol/chloroform (1 :1 ). This extraction by phenol and phenol/chloroform was repeated several times until no precipitate appeared at the interface of the extraction. The solution was then extracted with chloroform and the DNA was precipitated with 40 μl 0.3 M sodium acetate and 1 ml of ethanol. EXAMPLE VI Southern blot analysis of the recombinant DNA was conducted as follows:

Recombinant λgtll DNA (3 g) from Example 5 was digested with EcoR I and the resulting fragments were separated by agarose (0.8%) gel electrophoresis. The digested DNA was transferred by capillary action to a Nitran membrane filter in 10x SSPE Buffer (20x SSPE: 3 M NaCI, 0.2 M NaH2P04, and 20 mM EDTA). The filter was incubated at 45° C for 3 hr in prehybridization buffer [6x SSPE, 5x Denhardt's solution (0.1% Ficoll 400, 0.1% polyvinylpyrrolidone, 0.1 % bovine serum albumin, 0.5% SDS, and 100 μg/ml denatured and fragmented salmon sperm DNA) followed by incubation at 45° C overnight in the same buffer containing ³²P-labeled oligonucleotide probe (2x 10⁵ cpm; 10⁹ cpm/μg). The probe was synthesized according to the sequence deduced from the peptide sequence obtained from tryptic digestion of the light subunit. The filter was washed with 2x SSPE containing 0.5% SDS for 5 min at room temperature followed by washing with Ix SSPE 30 min at 45° C. Autoradiography was performed at room temperature overnight.

EXAMPLE VII DNA sequence analysis of the DNA according to the present invention was performed as follows:

The inserts of the recombinant λgtll phage DNA were excised by treatment with EcoRI, and isolated from agarose gel and purified using a Geneclean™ kit in accordance with the manufacture's instructions. The cDNAs were subcloned into the EcoRI site of the phagemid pBluescript KS-(+) (Strategene). The nucleotide sequence was determined on either pBluescript single or double stranded DNA by dideoxynucleotide chain termination method [see Proc. Natl. Acad. Sci. USA 74:5463 (1977)] using Sequenase (U.S. Biochemicals) according to the manufacturer's instructions. T7, SK primers, as well as the primers corresponding to internal light subunit sequence were used. Sequence analysis was performed using PC/Gene software.

The cDNA sequence of the light subunit was derived, as described above, from the cDNA inserts of the recombinant clone 62 and 71. The entire positive strand was sequenced at least three times from different overlapping sets using internal primers. The sequence was confirmed by sequencing the complementary strand twice.

The cDNA sequence corresponding to the light subunit of γ- glutamylcysteine synthetase mRNA is presented below:

GAATTCCGGC CTTCCCTCCG TGGCTCCGGC GCTGCCCGGT CCCCTCGGGC 50 GGCAGCTGCC 60

ATG GGC ACC GAC AGC CGC GCG GCC GGA GCA CTT CTG GCG 99

CGG GCC AGC ACC CTG CAC CTG CAG ACC GGG AAC CTG CTC 138 AAC TGG GGC CGC CTG CGG AAA AAG TGI CCG TCC ACG CAC 177

AGC GAG GAG CTT CGA GAC TGT ATC CAA AAG ACC TTG AAT 216

GAA TGG AGC TCC CAA ATC AGC CCT GAT TTG GTC AGG GAG 255

TTT CCA GAT GTT TTG GAA TGT ACC ATG TCC CAT GCA GTG 294

GAA AAG ATA AAC CCT GAT GAA AGA GAA GAA ATG AAA GTT 333 TCT GCT AAA CTG TTC ATT GTA GGA TCG AAT TCT TCA TCA 372

TCA ACT AGA AAT GCA GTT GAC ATG GCA TGC TCA GTC CTT 411

GGA GTT GCA CAG CTG GAC TCT GTC ATC ATG GCT TCC CCT 450

CCA ATT GAA GAT GGA GTT AAT CTT TCC TTG GAG CAT TTG 489

CAG CCT TAC TGG GAG GAA TTA GAA AAC TTA GTT CAG AGC 528 AAG AAG ATT GTT GCT ATA GGC ACC TCG GAT CTA GAC AAA 567

ACA CAG TTG GAG CAG CTG TAC CAG TGG GCA CAG GTA AAA 606

CCC AAT AGT AAT CAA GTT AAT CTT GCC TCC TGC TGT GTG 645

ATG CCA CCA GAT TTG ACT GCA TTT GCT AAA CAG TTT GAC 684

ATA CAG CTA CTG ACT CAC AAT GAC CCA AAA GAA CTG CTC 723 TCT GAG GCA AGT TTC CAG GAA GCT CTT CAA GAA AGC ATC 762

CCT GAC ATT GAA GCC CAG GAG TGG GTG CCA CTG TGG CTG 801

CTG AGG TAC TCG GTC ATC GTG AAA AGC AGA GGA ATC ATC 840

AAG TCA AAA GGA TAC ATT TTG CAA GCC AAA AGA AAG GGT 879 TCT 882 TAACTACAGC TCAAGCTCAC AACTCAGGGG CCTTGTATTT ATCTGGAACA 932 TAAGATAΆΆA ATTCATGATA AAATTGAGAT GTGTAAAAAA AAATCTAGCT 982 CTCGCCTACA AAAAGCGTCA CTGAGGCGTG AATGTGGTGG TTTGGCAATG 1032 TGTTGAGTTT AAGTACCTCC CTGGCGTCTG CAGCAGCGCA CTCACAGGAA 1082 GCATTGTATT CTCTTCATTA AACTCTTGGT TTCTAACTGA AATCGTCTAT 1132 AAAGAAAAAT ACTTGCAATA TATTTCCTTT ATTTTTATGA GTAATAGAAA 1182 TCAAGAAAAT TTGTTTTAAG ATATATTTTG GCTTAGGCAT CAGGGTGATG 1232 TATATACATA TTTTTTATTT CTAAAATTCA GTAACTGCTT CTTACTCTAT 1282 ACTTCTATAA CTAAGCAATT ACATTACAGT TGTTAAGACA TACTGGAAGA 1332 GATTTTTTTC CTGTCGTTTG ACAAAATAAT CTATCTCAGA GTCGGAATTC 1382 The sequence according to the present invention contains 1382 nucleotides and a open reading frame, indicated by triplet codons, of 822 nucleotides coding for 274 amino acid residues. The cDNA also has a 5'-nontranslational region of 60 nucleotides and a 3'-nontranslational region of 500 nucleotides. The first

ATG (position 61 ) is presumed to be the initiation codon because (a) the nucleotide sequence surrounding this codon (...GCCATGG...) agrees with the consensus sequence for eukaryotic initiation sites described by Kozak [see Nucleic Acid Research 12:857 (1984)] and (b) expression of the cDNA using this ATG as initiation codon produces a protein that co-migrates with the light subunit of isolated holoenzyme. The open reading frame sequence ends with a termination codon (TAA) at position 883, followed by 10 other termination codons. The predicted protein sequence, which contains the two independently determined peptide sequence (total 41 residues; 139-156 and 219-241 ), was found to be unique when compare with the protein sequence given in the Genbank# data base. The expressed open reading frame for the light subunit of γ-glutamylcysteine synthetase according to the present invention provides for the following peptide in which the two independently determined peptide sequence above are underlined is:

Mat Gly Thr Asp Ser Arg Ala Ala Gly Ala Leu Leu Ala Arg Ala

5 10 15 Ser Thr Leu His Leu Gin Thr Gly Asn Leu Leu Asn Trp Gly Arg

20 25 30

Leu Arg Lys Lys Cys Pro Ser Thr His Ser Glu Glu Leu Arg Asp

35 40 45 Cys He Gin Lys Thr Leu Asn Glu Trp Ser Ser Gin He Ser Pro

50 55 60

Asp Leu Val Arg Glu Phe Pro Asp Val Leu Glu Cys Thr Mat Ser

65 70 75

His Ala Val Glu Lys He Asn Pro Asp Glu Arg Glu Glu Mat Lys 80 85 90

Val Ser Ala Lys Leu Phe He Val Gly Ser Asn Ser Ser Ser Ser

95 100 105

Thr Arg Asn Ala Val Asp Mat Ala Cys Ser Val Leu Gly Val Ala

110 115 120 Gin Leu Asp Ser Val He Mat Ala- Ser Pro Pro He Glu Asp Gly

125 130 135

Val Asn Leu Ser Leu Glu His Leu Gin Pro Tyr Trp Gin Glu Leu

140 145 150

Glu Asn Leu Val Gin Ser Lys Lys He Val Ala He Gly Thr Ser 155 160 165

Asp Leu Asp Lys Thr Gin Leu Glu Gin Leu Tyr Gin Trp Ala Gin

170 175 180

Val Lys Pro Asn Ser Asn Gin Val Asn Leu Ala Ser Cys Cys Val

185 190 195 Mat Pro Pro Asp Leu Thr Ala Phe Ala Lys Gin Phe Asp He Gin

200 205 210

Leu Leu Thr His Asn Asp Pro Lys Glu Leu Leu Ser Glu Ala Ser

215 220 225

Phe Gin Glu Ala Leu Gin Glu Ser He Pro Asp He Glu Ala Gin 230 235 240

Glu Trp Val Pro Leu Trp Leu Leu Arg Tyr Ser Val He Val Lys

245 250 255

Ser Arg Gly He He Lys Ser Lys Gly Tyr He Leu Gin Ala Lys

260 265 270 Arg Lys Gly Ser

The amino acid composition of the light subunit of rat kidney γ-glutamylcysteine synthetase is as follows: Amino acid Isolated subunit Deduced frαn the cDNA. sequence

Asx 43 26

Glx 47 37

Cys* 7 6

Ser 26 29

Gly 22 11

His 8 5

Arg 12 11

Thr 10 11

Ala 19 20

Pro 19 13 ιyr 5 4

Val 17 18

Mat 7 6

He 12 15 leu 35 33

Phe 7 5

Lys 18 17 Trp 6 *determined as carboxymethylated cysteine

EXAMPLE VIII The construction of a light subunit expression plasmid was conducted according to the following:

The light subunit cDNA in plasmid pBluescript KS was digested with Ncol; the DNA was filled-in with four dNTPs using

T4 DNA polymerase and subsequently treated with BamHI [see Sambrook, supra]. The resulting DNA fragment (1 kb) was ligated [see Sambrook, supra} into expression vector pT7-7 which had previously been digested with Ndel (filled-in) and BamHI. The resulting plasmid (pRGCSL) (see Figure 1 ) contains the light subunit cDNA immediately downstream of a T7 promoter.

This plasmid is on deposit at the Cornell University Medical College, 1300 York Avenue, New York, New York, and will be made available to anyone requesting the plasmid from the inventors hereof in accordance with the Budapest Treaty.

EXAMPLE IX A co-expression plasmid in accordance with the present invention was constructed as follows:

The expression plasmid for the heavy subunit pRGCSH [see J. Biol. Chem (1993)] was digested with BstBI. The DNA was filled- in [see Sambrook, supra] using T4 DNA polymerase followed by digestion with Hind 111. The resulting 2-kb DNA fragment that contains a T7 promoter and the heavy subunit cDNA was ligated to plasmid pRGCSL (see Figure 1) which had been previously treated with Clal (filled-in) and Hindlll. The plasmid obtained (pRGCSHL) (see Figure 2) contains two T7 promoters in opposite directions immediately followed by the heavy and the light subunit respectively.

EXAMPLE X Purification of recombinant holoenzyme was conducted as follows:

Co-expression plasmid pRGCSHL (1 ng) was transformed into E. coli BL21 (DE3). This organism is on deposit at the Cornell

University Medical College, 1300 York Avenue, New York, New York, and will be made available to anyone requesting the plasmid-containing organism from the inventors hereof in accordance with the Budapest Treaty. The recombinant holoenzyme was expressed according to known methods as described in the literature [see J. Biol. Chem (1993)]. The enzyme was purified in the manner similar to that used in purification of the recombinant heavy subunit using recognized techniques [see Sambrook, supra]. The enzyme isolated from the ATP-agarose column was further purified on a ProteinPak™ 300 (Waters) HPLC gel filtration column previously equilibrated with imidazole buffer (10 mM; pH 7.4) containing 1 mM EDTA.

The purified recombinant holoenzyme exhibited a specific activity of 1 ,250 when assayed in a assay solution that contains 10 mM glutamate as depicted in the following table. This specific activity is similar to that of the holoenzyme isolated from rat kidney but is much higher.

Isolation Of Recombinant γ-glutamylcysteine synthetase holoenzyme

Volume Protein Activity Specific Activity

(ml) (mg) (units) (units/mg)

Step:

1 - Extract 61 520 6230 12

2 - DE52 120 95 5150 54

3 - ATP-agarose 11.5 6.4 4750 742

4 4 -- PPrrootein Pak 300 4.6 3.4 4230 250

The following table presents the Km values for the holoenzyme and heavy subunit of the GSH enzyme. In this table, the Km value is a reflection of the affinity of the substrate for the enzyme; a high value meaning a low affinity, and a low value means a high affinity.

Apparent Km values (mM) for γ-glutamylcysteine synthetase Enzvme preparation glutamate a-aminobutyrate cvsteine

Isolated holoenzyme 1.4 1.2 0.2 Co-expressed recombinant holoenzyme 1.8 1.1 0.2

Recombinant holoenzyme (mixed) 2.8 1.2 0.2 Recombinant heavy subunit 18.2 0.8 0.2

Thus, this table illustrates that the two types of recombinant enzyme (one made by co-expressing cDNA for light and cDNA for heavy subunits - and the other by simply mixing the separately expressed subunits) have affinity for glutamate, cysteine (and alpha-aminobutyrate) that is about the same as the isolated holoenzyme. However, the recombinant heavy enzyme has a value of 18.2 mM for glutamate indicating that this enzyme has about a 10-fold lower affinity for glutamate. This is, in fact, a key point of the present invention: it is shown that the heavy subunit alone (without the light) has too low an affinity for one of the substrates (glutamate) to be useful physiologically. Note also that the value for glutamate for the recombinant holoenzyme prepared by mixing the separately expressed light and heavy subunit is 2.8 mM, suggesting that mixing the subunits is not quite as efficient as co-expressing the subunits. With present technology, it is possible to synthesize either the nucleotide or peptide sequences according to the present invention using automated procedures. For example, the nucleotide sequence may be directly synthesized on an automated DNA synthesizer such as the Applied Biosystems Model 380A. At the time of synthesis, a large number of base, ribose and phosphate modifications can also be incorporated by substitution of the appropriate reagents for normal phosphoramidite chemistry.

Small oligonucleotides are spontaneously taken up from the surrounding medium by some cells, and this technique may be used to introduce the oligonucleotide according to the present invention into the appropriate cells to increase GSH levels within animal tissues. In addition, it is also within the present day purview of those skilled in the art to develop antisense sequences to the oligonucleotides according to the present invention and to introduce such antisense sequences into appropriate cells to inhibit GSH levels within animal tissues. Such uptake of both sense and antisense oligonucleotides may be facilitate by modification of the nucleic acid, as as derivatization with a hydrophobic moiety, substitution of methylphosphonates, phosphorothioates or dithioates for normally occurring phosphates. Liposome fusion provides another mode of delivering nucleic acid-based reagents to cells. Such techniques for manufacturing and delivery of oligonucleotides and peptides are well know in the art.

Thus, following the detailed description of the present invention and the examples contained therein, it can be deduced that the presented 274 amino acid sequence leads to a molecular weight (30,548) which is higher than that previously estimated (27,700) for the light subunit by SDS gel electrophoresis, and the calculated amino acid composition is in fair agreement with that determined by amino acid analysis of the isolated light subunit. Potential useful applications of the present invention include the possibility of increasing the amount of enzyme present in an animal by gene transfer (so-called "gene therapy"). A model for this type of gene transfer and for its potential usefulness has been found in connection with studies on a strain of E. coli whose radioresistance was enhanced by enrichment of its content of the enzyme required for glutathione synthesis by recombinant DNA techniques [see Proc. Natl. Acad. Sci. U.S. 86:1461 (1989)]. Gene transfer of the gene of the present invention would also be expected to give a similar result, and it would also be expected that the biochemical reactions associated with glutathione would also be enhanced by such a genetic transfer of this gene into an animal host. Of course, in most instances this gene would be transferred into the animal host along with promoters, inducers, and the like (which are well known and recognized techniques in the field of genetic engineering) to allow the cell to initiate and continue production of the genetic product protein. However, such potential applications are still not ready for commercialization, because of clinical testing and federal approvals required to routinely treat animals, including man, to increase their body's production of glutathione. Another potential application within the purview of the present application as described above is to introduce antisense oligonucleotide sequences to a cell as a means to inhibit GSH production by the cell. An earlier commercial use of the present invention is the potential of using the probes described above to assay and measure the concentration of mRNA for the enzyme in clinical specimens obtained from animal sources. The technology is in place to develop such a test around the present invention. A sequence listing of all nucleotide and peptide sequences disclosed herein follows:

SEQUENCE LISTING

(1 ) GENERAL INFORMATION:

(i) APPLICANT: Alton Meister, Chin-Shiou Huang, and Mary

E. Anderson

(ii) TITLE OF INVENTION: Glutamylcysteine Synthetase Light

Subunit (iii) NUMBER OF SEQUENCES: 10

(2) INFORMATION FOR SEQ ID NO: 1 :

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 23 amino acids

(B) TYPE: Amino Acid (D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 1 :

Glu Leu Leu Ser Glu Ala Ser Phe Gin Glu Ala Leu Gin Glu Ser

5 10 15 He Pro Asp He Glu Ala Gin Glu

20

(2) INFORMATION FOR SEQ ID NO: 2:

(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 amino acids (B) TYPE: Amino Acid

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide (ix) FEATURE:

(D) OTHER INFORMATION: position 9 is a undetermined sequence

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2:

Ser Leu Glu His Leu Gin Pro Tyr Xaa Glu Glu Leu Glu Asn Leu

5 10 15

Val Gin Ser (2) INFORMATION FOR SEQ ID NO: 3:

(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 7 amino acids (B) TYPE: Amino Acid (D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3: Phe Gin Glu Ala Leu Gin Glu

5

(2) INFORMATION FOR SEQ ID NO: 4:

(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 base pairs (B) TYPE: nucleic acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: mRNA

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4: UUU CAA GAA GCU CUU CAA GAA 21

(2) INFORMATION FOR SEQ ID NO: 5:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 20 base pairs

(B) TYPE: nucleic acid Acid (C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: DNA

(ix) OTHER INFORMATION: the designation "I" at positions 12 and 15 represents deoxyinosine (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 5:

TTT CAA GAA GCI CTI CAA GA 20

(2) INFORMATION FOR SEQ ID NO: 6:

(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1382 base pairs (B) TYPE: Nucleic Acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear

(ii) MOLECULE TYPE: cDNA

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 6: GAATTCCGGC CTTCCCTCCG TGGCTCCGGC GCTGCCCGGT CCCCTCGGGC 50 GGCAGCTGCC 60 ATG GGC ACC GAC AGC CGC GCG GCC GGA GCA CTT CTG GCG 99 CGG GCC AGC ACC CTG CAC CTG CAG ACC GGG AAC CTG CTC 138 AAC TGG GGC CGC CTG CGG AAA AAG TGT CCG TCC ACG CAC 177 AGC GAG GAG CTT CGA GAC TGT ATC CAA AAG ACC TTG AAT 216 GAA TGG AGC TCC CAA ATC AGC CCT GAT TTG GTC AGG GAG 255 TTT CCA GAT GTT TTG GAA TGT ACC ATG TCC CAT GCA GTG 294 GAA AAG ATA AAC CCT GAT GAA AGA GAA GAA ATG AAA GTT 333 TCT GCT AAA CTG TTC ATT GTA GGA TCG AAT TCT TCA TCA 372 TCA ACT AGA AAT GCA GTT GAC ATG GCA TGC TCA GTC CTT 411 GGA GTT GCA CAG CTG GAC TCT GTC ATC ATG GCT TCC CCT 450 CCA ATT GAA GAT GGA GTT AAT CTT TCC TTG GAG CAT TTG 489 CAG CCT TAC TGG GAG GAA TTA GAA AAC TTA GTT CAG AGC 528 AAG AAG ATT GTT GCT ATA GGC ACC TCG GAT CTA GAC AAA 567 ACA CAG TTG GAG CAG CTG TAC CAG TGG GCA CAG GTA AAA 606 CCC AAT AGT AAT CAA GTT AAT CTT GCC TCC TGC TGT GTG 645

ATG CCA CCA GAT TTG ACT GCA TTT GCT AAA CAG TTT GAC 684 ATA CAG CTA CTG ACT CAC AAT GAC CCA AAA GAA CTG CTC 723 TCT GAG GCA AGT TTC CAG GAA GCT CTT CAA GAA AGC ATC 762 CCT GAC ATT GAA GCC CAG GAG TGG GTG CCA CTG TGG CTG 801 CTG AGG TAC TCG GTC ATC GTG AAA AGC AGA GGA ATC ATC 840

AAG TCA AAA GGA TAC ATT TTG CAA GCC AAA AGA AAG GGT 879 TCT 882

TAACTACAGC TCAAGCTCAC AACTCAGGGG CCTTGTATTT ATCTGGAACA 932 TAAGATAAAA ATTCATGATA AAATTGAGAT GTGTAAAAAA AAATCTAGCT 982 CTCGCCTACA AAAAGCGTCA CIGAGGCGTG AATGTGGTGG TTTGGCAATG 1032

TGTTGAGTTT AAGTACCTCC CTGGCGTCTG CAGCAGCGCA CTCACAGGAA 1082 GCATTGTATT CTCTTCATTA AACTCTTGGT TTCTAACTGA AATCGTCTAT 1132 AAAGAAAAAT ACTTGCAATA TATTTCCTTT ATTTTTATGA GTAATAGAAA 1182 TCAAGAAAAT TTGTTTTAAG ATATATTTTG GCTTAGGCAT CAGGGTGATG 1232 TATATACATA TTTTTTATTT CTAAAATTCA GTAACTGCTT CTTACTCTAT 1282

ACTTCTATAA CTAAGCAATT ACATTACAGT TGTTAAGACA TACTGGAAGA 1332 GATTTTTTTC CTGTCGTTTG ACAAAATAAT CTATCTCAGA GTCGGAATTC 1382

(2) INFORMATION FORSEQ ID NO:7:

(i) SEQUENCECHARACTERISTICS: (A) LENGTH: 274 amino acids

(B) TYPE: Amino Acid (D) TOPOLOGY: linear

(ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 7:

Mat Gly Thr Asp Ser Arg Ala Ala Gly Ala Leu Leu Ala Arg Ala

5 10 15

Ser Thr Leu His Leu Gin Thr Gly Asn Leu Leu Asn Trp Gly Arg

20 25 30 Leu Arg Lys Lys Cys Pro Ser Thr His Ser Glu Glu Leu Arg Asp

35 40 45

Cys He Gin Lys Thr Leu Asn Glu Trp Ser Ser Gin He Ser Pro

50 55 60

Asp Leu Val Arg Glu Phe Pro Asp Val Leu Glu Cys Thr Met Ser 65 70 75

His Ala Val Glu Lys He Asn Pro Asp Glu Arg Glu Glu Mat Lys

80 85 90

Val Ser Ala Lys Leu Phe He Val Gly Ser Asn Ser Ser Ser Ser

95 100 105 Thr Arg Asn Ala Val Asp Mat Ala Cys Ser Val Leu Gly Val Ala

110 115 120

Gin Leu Asp Ser Val He Mat Ala Ser Pro Pro He Glu Asp Gly

125 130 135

Val Asn Leu Ser Leu Glu His Leu Gin Pro Tyr Trp Glu Glu Leu 140 145 150

Glu Asn Leu Val Gin Ser Lys Lys He Val Ala He Gly Thr Ser

155 160 165

Asp Leu Asp Lys Thr Gin Leu Glu Gin Leu Tyr Gin Trp Ala Gin

170 175 180 Val Lys Pro Asn Ser Asn Gin Val Asn Leu Ala Ser Cys Cys Val

185 190 195

Met Pro Pro Asp Leu Thr Ala Phe Ala Lys Gin Phe Asp He Gin

200 205 210

Leu Leu Thr His Asn Asp Pro Lys Glu Leu Leu Ser Glu Ala Ser 215 220 225

Phe- Gin Glu Ala Leu Gin Glu Ser He Pro Asp He Glu Ala Gin

230 235 240

Glu Trp Val Pro Leu Trp Leu Leu Arg Tyr Ser Val He Val Lys

245 250 255 Ser Arg Gly He He Lys Ser Lys Gly Tyr He Leu Gin Ala Lys

260 265 270 Arg Lys Gly Ser

(2) INFORMATION FOR SEQ ID NO: 8:

(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 base pairs (B) TYPE: Nucleic Acid

(C) STRANDEDNESS: single

(D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 8: TTC CAG GAA GCT CTT CAA GA 20

(2) INFORMATION FOR SEQ ID NO: 9:

(i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 1914 base pairs

(B) TYPE: Nucleic Acid (C) STRANDEDNESS: single

(D) TOPOLOGY: linear (ii) MOLECULE TYPE: DNA (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 9:

ATG GGG CTG CTG TCC CAA GGC TCG CCA CTG AGC TGG GAA 39 GAG ACC CAG CGC CAC GCC GAC CAC GTG CGG AGA CAC GGC 78

ATC CTC CAG TTC CTG CAC ATC TAC CAC GCA GTC AAG GAC 117

CGG CAC AAG GAC GTG CTC AAG TGG GGT GAC GAG GTG GAG 156

TAC ATG TTG GTG TCC TTT GAT CAT GAA AAT AGG AAA GTC 195

CAG TTG TTA CTG AAT GGC GGC GAT GTT CTT GAA ACT CTG 234 CAA GAG AAG GGG GAG AGG ACA AAC CCC AAC CAC CCA ACC 273

CTC TGG AGA CCA GAG TAT GGG AGT TAC ATG ATT GAA GGG 312

ACA CCT GGC CAG CCG TAC GGA GGA ACG ATG TCC GAG TTC 351

AAC ACA GTG GAG GAC AAC ATG AGG AAA CGC CGG AAG GAG 390

GCT ACT TCT GTA TTA GGA GAA CAT CAG GCT CTT TCG ACG 429 ATA ACT TCA TTT CCC AGG CTA GGC TGC CCT GGA TTC ACA 468

CTG CCA GAG CAC AGA CCC AAC CCA GAG GAA GGA GGT GCA 507

TCT AAG TCC CTC TTC TTT CCA GAC GAA GCC ATA AAC AAG 546

CAC CCC CGC TTT GGT ACT CTA ACA AGA AAC ATC CGG CAT 585

CGG AGA GGA GAA AAG GTT GTC ATC AAT GTG CCA ATA TTC 624 AAG GAC AAG AAC ACA CCA TCT CCG TTT GTA GAA ACA TTT 663 CCT GAG GAT GAG GAG GCA TCA AAG GCC TCT AAG CCA GAC 702 CAC ATC TAC ATG GAT GCC ATG GGA TTT GGG ATG GGC AAC 741 TGC TGT CTT CAG GTG ACA TTC CAA GCC TGC AGT ATA TCT 780 GAG GCA AGA TAC CTT TAT GAC CAG TTG GCC ACT ATC TGC 819 CCA ATT GTT ATG GCT TTG AGT GCT GCA TCG CCA TTT TAC 858 CGA GGC TAC GTG TCA GAC ATT GAT TGT CGC TCG GGA GTG 897 ATT TCT GCA TCT GTA GAT GAT AGA ACA CGG GAG GAG AGA 936 GGA CTG GAG CCC CTG AAG AAC AAT CGC TTT AAA ATC AGT 975 AAG TCT CGG TAT GAC TCA ATA GAT AGC TAC CTG TCC AAG 1014 TGT GGA GAG AAG TAC AAT GAC ATC GAC CTG ACC ATC GAC 1053 ACG GAG ATC TAC GAG CAG CTC TAA GAG GAA GGC ATC GAT 1092 CAC CTT CTG GCA CAG CAG GTT GCT CAT CTC TTT ATT AGA 1131 GAC CCA CTG ACC CTT TTT GAA GAG AAA ATT CAT CTG GAT 1170 GAT GCC AAC GAG TCT GAC CAT TTT GAG AAT ATT CAG TCC 1209 ACA AAC TGG CAG ACA ATG AGG TTT AAG CCT CCT CCT CCA 1248

AAC TCA GAT ATT GGA TGG AGA GTA GAG TTC CGA CCA ATG 1287 GAG GTA CAG TTG ACA GAC TTT GAG AAC TCT GCC TAT GTG 1326 GTA TTT GTG GTA CTG CTG ACC AGG GTG ATC CTC TCA TAC 1365 AAA CTA GAC TTC CTC ATT CCA CTG TCC AAG GTT GAC GAG 1404 AAC ATG AAA GTG GCA CAG GAG CGA GAT GCC GTC TTA CAG 1443

GGG ATG TTT TAT TTC AGG AAA GAC ATT TGC AAA GGT GGC 1482 AAC GCC GTG GTG GAT GGG TGT AGC AAG GCC CAG ACC AGC 1521 TCC GAG CCA TCT GCA GAG GAG TAC ACG CTC ATG AGC ATA 1560 GAC ACC ATC ATC AAT GGG AAG GAA GGC GTG TTT CCT GGA 1599 CTC ATC CCC ATT CTG AAC TCC TAC CTT GAA AAC ATG GAA 1638

GTC GAC GTG GAC ACC CGA TGC AGT ATT CTG AAC TAC CTG 1677 AAG CTA ATT AAG AAG AGA GCA TCT GGA GAA CTA ATG ACT 1716 GTT GCC AGG TGG ATG AGA GAG TTT ATT GCA AAC CAT CCT 1755 GAC TAC AAG CAA GAC AGT GTA ATA ACT GAT GAG ATC AAC 1794 TAT AGC CTC ATT TTG AAA TGC AAT CAA ATT GCA AAT GAA 1833

TTG TGT GAA TGT CCA GAG TTA CTT GGA TCA GGC TTT AGA 1872 AAA GCG AAG TAC AGT GGA GGT AAA AGC GAC CCT TCA GAC 1911 TAG 1914

(2) INFORMATION FORSEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS:

(A) LENGTH: 637 amino acids

(B) TYPE: Amino Acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide

(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 10:

Mat Gly Leu Leu Ser Gin Gly Ser Pro Leu Ser Trp Glu Glu Thr

5 10 15

Gin Arg His Ala Asp His Val Arg Arg His Gly He Leu Gin Phe 20 25 30

Leu His He Tyr His Ala Val Lys Asp Arg His Lys Asp Val Leu

35 40 ^' 45

Lys Trp Gly Asp Glu Val Glu Tyr Mat Leu Val Ser Phe Asp His

50 55 60 Glu Asn Arg Lys Val Gin Leu Leu Leu Asn Gly Gly Asp Val Leu

65 70 75

Glu Thr Leu Gin Glu Lys Gly Glu Arg Thr Asn Pro Asn His Pro

80 85 90

Thr Leu Trp Arg Pro Glu Tyr Gly Ser Tyr Mat He Glu Gly Thr 95 100 105

Pro Gly Gin Pro Tyr Gly Gly Thr Mat Ser Glu Phe Asn Thr Val

110 115 120

Glu Asp Asn Mat Arg Lys Arg Arg Lys Glu Ala Thr Ser Val Leu

125 130 135 Gly Glu His Gin Ala Leu Cys Thr He Thr Ser Phe Pro Arg Leu

140 145 150

Gly Cys Pro Gly Phe Thr Leu Pro Glu His Arg Pro Asn Pro Glu

155 160 165

Glu Gly Gly Ala Ser Lys Ser Leu Phe Phe Pro Asp Glu Ala He 170 175 180

Asn Lys His Pro Arg Phe Gly Thr Leu Thr Arg Asn He Arg His

185 190 195

Arg Arg Gly Glu Lys Val Val He Asn Val Pro He Phe Lys Asp

200 205 210 Lys Asn Thr Pro Ser Pro Phe Val Glu Thr Phe Pro Glu Asp Glu

215 220 225

Glu Ala Ser Lys Ala Ser Lys Pro Asp His He Tyr Mat Asp Ala

230 235 240

Mat Gly Phe Gly Mat Gly Asn Cys Cys Leu Gin Val Thr Phe Gin 245 250 255 Ala Cys Ser He Ser Glu Ala Arg Tyr Leu Tyr Asp Gin Leu Ala

260 265 270

Thr He Cys Pro He Val Mat Ala Leu Ser Ala Ala Ser Pro Phe

275 280 285 Tyr Arg Gly Tyr Val Ser Asp He Asp Cys Arg Trp Gly Val He

290 295 300

Ser Ala Ser Val Asp Asp Arg Thr Arg Glu Glu Arg Gly Leu Glu

305 310 315

Pro Leu Lys Asn Asn Arg Phe Lys He Ser Lys Ser Arg Tyr Asp 320 325 330

Ser He Asp Ser Tyr Leu Ser Lys Cys Gly Glu Lys Tyr Asn Asp

335 340 345

He Asp Leu Thr He Asp Thr Glu He Tyr Glu Gin Leu Leu Glu

350 355 360 Glu Gly He Asp His Leu Leu Ala Gin His Val Ala His Leu Phe

365 370 375

He Arg Asp Pro Leu Thr Leu Phe Glu Glu Lys He His Leu Asp

380 385 390

Asp Ala Asn Glu Ser Asp His Phe Glu Asn He Gin Ser Thr Asn 395 400 405

Trp Gin Thr Mat Arg Phe Lys Pro Pro Pro Pro Asn Ser Asp He

410 415 420

Gly Trp Arg Val Glu Phe Arg Pro Mat Glu Val Gin Leu Thr Asp

425 ^■ 430 435 Phe Glu Asn Ser Ala Tyr Val Val Phe Val Val Leu Leu Thr Arg

440 445 450

Val He Leu Ser Tyr Lys Leu Asp Phe Leu He Pro Leu Ser Lys

455 460 465

Val Asp Glu Asn Mat Lys Val Ala Gin Glu Arg Asp Ala Val Leu 470 475 480

Gin Gly Mat Phe Tyr Phe Arg Lys Asp He Cys Lys Gly Gly Asn

485 490 495

Ala Val Val Asp Gly Cys Ser Lys Ala Gin Thr Ser Ser Glu Pro

500 505 510 Ser Ala Glu Glu Tyr Thr Leu Mat Ser He Asp Thr He He Asn

515 520 525

Gly Lys Glu Gly Val Phe Pro Gly Leu He Pro He Leu Asn Ser

530 535 540

Tyr Leu Glu Asn Mat Glu Val Asp Val Asp Thr Arg Cys Ser He 545 550 555 Leu Asn Tyr Leu Lys Leu He Lys Lys Arg Ala Ser Gly Glu Leu

560 565 570

Mat Thr Val Ala Arg Trp Mat Arg Glu Phe He Ala Asn His Pro

575 580 585 Asp Tyr Lys Gin Asp Ser Val He Thr Asp Glu He Asn Tyr Ser

590 595 600

Leu He Leu Lys Cys Asn Gin He Ala Asn Glu Leu Cys Glu Cys

605 610 615

Pro Glu Leu Leu Gly Ser Gly Phe Arg Lys Ala Lys Tyr Ser Gly 620 625 630

Gly Lys Ser Asp Pro Ser Asp

635

Thus while we have illustrated and described the preferred embodiment of our invention, it is to be understood that this invention is capable of variation and modification, and we therefore do not wish to be limited to the precise terms set forth, but desire to avail ourselves of such changes and alterations which may be made for adapting the invention to various usages and conditions. Accordingly, such changes and alterations are properly intended to be within the full range of equivalents, and therefore within the purview of the following claims.

Having thus described our invention and the manner and a process of making and using it in such full, clear, concise and exact terms so as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same;

Claims

WECLAIM:

1. An isolated cDNA sequence corresponding to the light subunit of γ-glutamylcysteine synthetase mRNA which is:

GAATTCCGGC CTTCCCTCCG TGGCTCCGGC GCTGCCCGGT CCCCTCGGGC 50 GGCAGCTGCC 60

ATG GGC ACC GAC AGC CGC GCG GCC GGA GCA CTT CTG GCG 99 CGG GCC AGC ACC CTG CAC CTG CAG ACC GGG AAC CTG CTC 138 AAC TGG GGC CGC CTG CGG AAA AAG TGT CCG TCC ACG CAC 177 AGC GAG GAG CTT CGA GAC TGT ATC CAA AAG ACC TTG AAT 216 GAA TGG AGC TCC CAA ATC AGC CCT GAT TTG GTC AGG GAG 255 TTT CCA GAT GTT TTG GAA TGT ACC ATG TCC CAT GCA GTG 294 GAA AAG ATA AAC CCT GAT GAA AGA GAA GAA ATG AAA GTT 333 TCT GCT AAA CTG TTC ATT GTA GGA TCG AAT TCT TCA TCA 372 TCA ACT AGA AAT GCA GTT GAC ATG GCA TGC TCA GTC CTT 411 GGA GTT GCA CAG CTG GAC TCT GTC ATC ATG GCT TCC CCT 450 CCA ATT GAA GAT GGA GTT AAT CTT TCC TTG GAG CAT TTG 489 CAG CCT TAC TGG GAG GAA TTA GAA AAC TTA GTT CAG AGC 528 AAG AAG ATT GTT GCT ATA GGC ACC TCG GAT CTA GAC AAA 567 ACA CAG TTG GAG CAG CTG TAC CAG TGG GCA CAG GTA AAA 606 CCC AAT AGT AAT CAA GTT AAT CTT GCC TCC TGC TGT GTG 645 ATG CCA CCA GAT TTG ACT GCA TTT GCT AAA CAG TTT GAC 684 ATA CAG CTA CTG ACT CAC AAT GAC CCA AAA GAA CTG CTC 723 TCT GAG GCA AGT TTC CAG GAA GCT CTT CAA GAA AGC ATC 762 CCT GAC ATT GAA GCC CAG GAG TGG GTG CCA CTG TGG CTG 801 CTG AGG TAC TCG GTC ATC GTG AAA AGC AGA GGA ATC ATC 840 AAG TCA AAA GGA TAC ATT TTG CAA GCC AAA AGA AAG GGT 879 TCT 882

TAACTACAGC TCAAGCTCAC AACTCAGGGG CCTTGTATTT ATCTGGAACA 932 TAAGATAAAA ATTCATGATA AAATTGAGAT GTGTAAAAAA AAATCTAGCT 982 CTCGCCTACA AAAAGCGTCA CTGAGGCGTG AATGTGGTGG TTTGGCAATG 1032 TGTTGAGTTT AAGTACCTCC CTGGCGTCTG CAGCAGCGCA CTCACAGGAA 1082 GCATTCTATT CTCTTCATTA AACTCTTGGT TTCTAACTGA AATCGTCTAT 1132 AAAGAAAAAT ACTTGCAATA TATTTCCTTT ATTTTTATGA GTAATAGAAA 1182 TCAAGAAAAT TTGTTTTAAG ATATATTTTG GCTTAGGCAT CAGGGTGATG 1232 TATATACATA TTTTTTATTT CTAAAATTCA GTAACTGCTT CTTACTCTAT 1282 ACTTCTATAA CTAAGCAATT ACATTACAGT TGTTAAGACA TACTGGAAGA 1332 GATTTTTTTC CTGTCGTTTG ACAAAATAAT CTATCTCAGA GTCGGAATTC 1382 said sequence containing an open reading frame indicated by 822 triplet nucleotide codons coding for 274 amino acid residues, a 5'-nontranslational region of 60 nucleotides, and a 3'- nontranslational region of 500 nucleotides.

2. The sequence according to Claim 1 which is the open reading frame indicated by triplet nucleotide codons 61 to 822 nucleotides coding for 274 amino acid residues which is

ATG GGC ACC GAC AGC CGC GCG GCC GGA GCA CTT CTG GCG 99

CGG GCC AGC ACC CTG CAC CTG CAG ACC GGG AAC CTG CTC 138

AAC TGG GGC CGC CTG CGG AAA AAG TGT CCG TCC ACG CAC 177

AGC GAG GAG CTT CGA GAC TGI ATC CAA AAG ACC TTG AAT 216 GAA TGG AGC TCC CAA ATC AGC CCT GAT TTG GTC AGG GAG 255

TTT CCA GAT GTT TTG GAA TGT ACC ATG TCC CAT GCA GTG 294

GAA AAG ATA AAC CCT GAT GAA AGA GAA GAA ATG AAA GTT 333

TCT GCT AAA CTG TTC ATT GTA GGA TCG AAT TCT TCA TCA 372

TCA ACT AGA AAT GCA GTT GAC ATG GCA TGC TCA GTC CTT 411 GGA GTT GCA CAG CTG GAC TCT GTC ATC ATG GCT TCC CCT 450

CCA ATT GAA GAT GGA GTT AAT CTT TCC TTG GAG CAT TTG 489

CAG CCT TAC TGG GAG GAA TTA GAA AAC TTA GTT CAG AGC 528

AAG AAG ATT GTT GCT ATA GGC ACC TCG GAT CTA GAC AAA 567

ACA CAG TTG GAG CAG CTG TAC CAG TGG GCA CAG GTA AAA 606 CCC AAT AGT AAT CAA GTT AAT CTT GCC TCC TGC TGT GTG 645

ATG CCA CCA GAT TTG ACT GCA TTT GCT AAA CAG TTT GAC 684

ATA CAG CTA CTG ACT CAC AAT GAC CCA AAA GAA CTG CTC 723

TCT GAG GCA AGT TTC CAG GAA GCT CTT CAA GAA AGC ATC 762

CCT GAC ATT GAA GCC CAG GAG TGG GTG CCA CTG TGG CTG 801 CTG AGG TAC TCG GTC ATC GTG AAA AGC AGA GGA ATC ATC 840

AAG TCA AAA GGA TAC ATT TTG CAA GCC AAA AGA AAG GGT 879 TCT 882 3. An isolated and purified peptide which is the light subunit of γ-glutamylcysteine synthetase having the following amino acid sequence:

Mat Gly Thr Asp Ser Arg Ala Ala Gly Ala Leu Leu Ala Arg Ala 5 10 15

Ser Thr Leu His Leu Gin Thr Gly Asn Leu Leu Asn Trp Gly Arg

20 25 30

Leu Arg Lys Lys Cys Pro Ser Thr His Ser Glu Glu Leu Arg Asp

35 40 45 Cys He Gin Lys Thr Leu Asn Glu Trp Ser Ser Gin He Ser Pro

50 55 60

Asp Leu Val Arg Glu Phe Pro Asp Val Leu Glu Cys Thr Mat Ser

65 70 75

His Ala Val Glu Lys He Asn Pro Asp Glu Arg Glu Glu Mat Lys 80 85 90

Val Ser Ala Lys Leu Phe He Val Gly Ser Asn Ser Ser Ser Ser

95 100 105

Thr Arg Asn Ala Val Asp Mat Ala Cys Ser Val Leu Gly Val Ala

110 115 120 Gin Leu Asp Ser Val He Mat Ala Ser Pro Pro He Glu Asp Gly

125 130 135

Val Asn Leu Ser Leu Glu His Leu Gin Pro Tyr Trp Glu Glu Leu

140 145 150

Glu Asn Leu Val Gin Ser Lys Lys He Val Ala He Gly Thr Ser 155 160 165

Asp Leu Asp Lys Thr Gin Leu Glu Gin Leu Tyr Gin Trp Ala Gin

170 175 180

Val Lys Pro Asn Ser Asn Gin Val Asn Leu Ala Ser Cys Cys Val

185 190 195 Mat Pro Pro Asp Leu Thr Ala Phe Ala Lys Gin Phe Asp He Gin

200 205 210

Leu Leu Thr His Asn Asp Pro Lys Glu Leu Leu Ser Glu Ala Ser

215 220 225

Phe Gin Glu Ala Leu Gin Glu Ser He Pro Asp He Glu Ala Gin 230 235 240

Glu Trp Val Pro Leu Trp Leu Leu Arg Tyr Ser Val He Val Lys

245 250 255

Ser Arg Gly He He Lys Ser Lys Gly Tyr He Leu Gin Ala Lys

260 265 270 Arg Lys Gly Ser 4. A method for increasing a cell's normal levels of GSH production which comprises introducing into such cell in which an increase of GSH level production is desired the oligonucleotide sequence of GAATTCCGGC CTTCCCTCCG TGGCTCCGGC GCTGCCCGGT CCCCTCGGGC 50 GGCAGCTGCC 60

ATG GGC ACC GAC AGC CGC GCG GCC GGA GCA CTT CTG GCG 99 CGG GCC AGC ACC CTG CAC CTG CAG ACC GGG AAC CTG CTC 138 AAC TGG GGC CGC CTG CGG AAA AAG TGT CCG TCC ACG CAC 177 AGC GAG GAG CTT CGA GAC TGT ATC CAA AAG ACC TTG AAT 216 GAA TGG AGC TCC CAA ATC AGC CCT GAT TTG GTC AGG GAG 255 TTT CCA GAT GTT TTG GAA TGT ACC_. ATG TCC CAT GCA GTG 294 GAA AAG ATA AAC CCT GAT GAA AGA GAA GAA ATG AAA GTT 333 TCT GCT AAA CTG TTC ATT GTA GGA TCG AAT TCT TCA TCA 372 TCA ACT AGA AAT GCA GTT GAC ATG GCA TGC TCA GTC CTT 411 GGA GTT GCA CAG CTG GAC TCT GTC ATC ATG GCT TCC CCT 450 CCA ATT GAA GAT GGA GTT AAT CTT TCC TTG GAG CAT TTG 489 CAG CCT TAC TGG GAG GAA TTA GAA AAC TTA GTT CAG AGC 528 AAG AAG ATT GTT GCT ATA GGC ACC TCG GAT CTA GAC AAA 567 ACA CAG TTG GAG CAG CTG TAC CAG TGG GCA CAG GTA AAA 606 CCC AAT AGT AAT CAA GTT AAT CTT GCC TCC TGC TGT GTG 645 ATG CCA CCA GAT TTG ACT GCA TTT GCT AAA CAG TTT GAC 684 ATA CAG CTA CTG ACT CAC AAT GAC CCA AAA GAA CTG CTC 723 TCT GAG GCA AGT TTC CAG GAA GCT CTT CAA GAA AGC ATC 762 CCT GAC ATT GAA GCC CAG GAG TGG GTG CCA CTG TGG CTG 801 CTG AGG TAC TCG GTC ATC GTG AAA AGC AGA GGA ATC ATC 840 AAG TCA AAA GGA TAC ATT TTG CAA GCC AAA AGA AAG GGT 879 TCT 882 TAACTACAGC TCAAGCTCAC AACTCAGGGG CCTTGTATTT ATCTGGAACA 932 TAAGATAAAA ATTCATGATA AAATTGAGAT GTGTAAAAAA AAATCTAGCT 982 CTCGCCTACA AAAAGCGTCA CTGAGGCGTG AATGTGGTGG TTTGGCAATG 1032 TGTTGAGTTT AAGTACCTCC CTGGCGTCTG CAGCAGCGCA CTCACAGGAA 1082 GCATTCTATT CTCTTCATTA AACTCTTGGT TTCTAACTGA AATCGTCTAT 1132 AAAGAAAAAT ACTTGCAATA TATTTCCTTT ATTTTTATGA GTAATAGAAA 1182 TCAAGAAAAT TTGTTTTAAG ATATATTTTG GCTTAGGCAT CAGGGTGATG 1232 TATATACATA TTTTTTATTT CTAAAATTCA GTAACTGCTT CTTACTCTAT 1282 ACTTCTATAA CTAAGCAATT ACATTACAGT TGTTAAGACA TACTGGAAGA 1332 GATTTTTTTC CTGTCGTTTG ACAAAATAAT CTATCTCAGA GTCGGAATTC 1382 5. A method according to Claim 4 in which the sequence introduced into the cell is the open reading frame defined by nucleotides 61 to 822.

6. A method according to Claim 5 which also comprises introducing into such cell an oligonucleotide sequence of ATG GGG CTG CTG TCC CAA GGC TCG CCA CTG AGC TGG GAA 39

GAG ACC CAG CGC CAC GCC GAC CAC GTG CGG AGA CAC GGC 78

ATC CTC.CAG TTC CTG CAC ATC TAC CAC GCA GTC AAG GAC 117

CGG CAC AAG GAC GTG CTC AAG TGG GGT GAC GAG GTG GAG 156

TAC ATG TTG GTG TCC TTT GAT CAT GAA AAT AGG AAA GTC 195 CAG TTG TTA CTG AAT GGC GGC GAT GTT CTT GAA ACT CTG 234

CAA GAG AAG GGG GAG AGG ACA AAC CCC AAC CAC CCA ACC 273

CTC TGG AGA CCA GAG TAT GGG AGT TAC ATG ATT GAA GGG 312

ACA CCT GGC CAG CCG TAC GGA GGA ACG ATG TCC GAG TTC 351

AAC ACA GTG GAG GAC AAC ATG AGG AAA CGC CGG AAG GAG 390 GCT ACT TCT GTA TTA GGA GAA CAT CAG GCT CTT TCG ACG 429

ATA ACT TCA TTT CCC AGG CTA GGC TGC CCT GGA TTC ACA 468

CTG CCA GAG CAC AGA CCC AAC CCA GAG GAA GGA GGT GCA 507

TCT AAG TCC CTC TTC TTT CCA GAC GAA GCC ATA AAC AAG 546

CAC CCC CGC TTT GGT ACT CTA ACA AGA AAC ATC CGG CAT 585 CGG AGA GGA GAA AAG GTT GTC ATC AAT GTG CCA ATA TTC 624

AAG GAC AAG AAC ACA CCA TCT CCG TTT GTA GAA ACA TTT 663

CCT GAG GAT GAG GAG GCA TCA AAG GCC TCT AAG CCA GAC 702

CAC ATC TAC ATG GAT GCC ATG GGA TTT GGG ATG GGC AAC 741

TGC TGT CTT CAG GTG ACA TTC CAA GCC TGC AGT ATA TCT 780 GAG GCA AGA TAC CTT TAT GAC CAG TTG GCC ACT ATC TGC 819

CCA ATT GTT ATG GCT TTG AGT GCT GCA TCG CCA TTT TAC 858

CGA GGC TAC GTG TCA GAC ATT GAT TGT CGC TCG GGA GTG 897

ATT TCT GCA TCT GTA GAT GAT AGA ACA CGG GAG GAG AGA 936

GGA CTG GAG CCC CTG AAG AAC AAT CGC TTT AAA ATC AGT 975 AAG TCT CGG TAT GAC TCA ATA GAT AGC TAC CTG TCC AAG 1014 TGT GGA GAG AAG TAC AAT GAC ATC GAC CTG ACC ATC GAC 1053 ACG GAG ATC TAC GAG CAG CTC TAA GAG GAA GGC ATC GAT 1092 CAC CTT CTG GCA CAG CAG GTT GCT CAT CTC TTT ATT AGA 1131 GAC CCA CTG ACC CTT TTT GAA GAG AAA ATT CAT CTG GAT 1170 GAT GCC AAC GAG TCT GAC CAT TTT GAG AAT ATT CAG TCC 1209 ACA AAC TGG CAG ACA ATG AGG TTT AAG CCT CCT CCT CCA 1248 AAC TCA GAT ATT GGA TGG AGA GTA GAG TTC CGA CCA ATG 1287 GAG GTA CAG TTG ACA GAC TTT GAG AAC TCT GCC TAT GTG 1326 GTA TTT GTG GTA CTG CTG ACC AGG GTG ATC CTC TCA TAC 1365 AAA CTA GAC TTC CTC ATT CCA CTG TCC AAG GTT GAC GAG 1404 AAC ATG AAA GTG GCA CAG GAG CGA GAT GCC GTC TTA CAG 1443 GGG ATG TTT TAT TTC AGG AAA GAC ATT TGC AAA GGT GGC 1482 AAC GCC GTG GTG GAT GGG TGT AGC AAG GCC CAG ACC AGC 1521 TCC GAG CCA TCT GCA GAG GAG TAC ACG CTC ATG AGC ATA 1560 GAC ACC ATC ATC AAT GGG AAG GAA GGC GTG TTT CCT GGA 1599 CTC ATC CCC ATT CTG AAC TCC TAC CTT GAA AAC ATG GAA 1638 GTC GAC GTG GAC ACC CGA TGC AGT ATT CTG AAC TAC CTG 1677 AAG CTA ATT AAG AAG AGA GCA TCT GGA GAA CTA ATG ACT 1716 GTT GCC AGG TGG ATG AGA GAG TTT ATT GCA AAC CAT CCT 1755 GAC TAC AAG CAA GAC AGT GTA ATA ACT GAT GAG ATC AAC 1794 TAT AGC CTC ATT TTG AAA TGC AAT CAA ATT GCA AAT GAA 1833 TTG TGT GAA TGT CCA GAG TTA CTT GGA TCA GGC TTT AGA 1872 AAA GCG AAG TAC AGT GGA GGT AAA AGC GAC CCT TCA GAC 1911 TAG 1914

7. A method according to Claim 4 which also comprises introducing into such cell an oligonucleotide sequence of

ATG GGG CTG CTG TCC CAA GGC TCG CCA CTG AGC TGG GAA 39

GAG ACC CAG CGC CAC GCC GAC CAC GTG CGG AGA CAC GGC 78 ATC CTC CAG TTC CTG CAC ATC TAC CAC GCA GTC AAG GAC 117

CGG CAC AAG GAC GTG CTC AAG TGG GGT GAC GAG GTG GAG 156

TAC ATG TTG GTG TCC TTT GAT CAT GAA AAT AGG AAA GTC 195

CAG TTG TTA CTG AAT GGC GGC GAT GTT CTT GAA ACT CTG 234

CAA GAG AAG GGG GAG AGG ACA AAC CCC AAC CAC CCA ACC 273 CTC TGG AGA CCA GAG TAT GGG AGT TAC ATG ATT GAA GGG 312 ACA CCT GGC CAG CCG TAC GGA GGA ACG ATG TCC GAG TTC 351 AAC ACA GTG GAG GAC AAC ATG AGG AAA CGC CGG AAG GAG 390 GCT ACT TCT GTA TTA GGA GAA CAT CAG GCT CTT TCG ACG 429 ATA ACT TCA TTT CCC AGG CTA GGC TGC CCT GGA TTC ACA 468 CTG CCA GAG CAC AGA CCC AAC CCA GAG GAA GGA GGT GCA 507 TCT AAG TCC CTC TTC TTT CCA GAC GAA GCC ATA AAC AAG 546 CAC CCC CGC TTT GGT ACT CTA ACA AGA AAC ATC CGG CAT 585 CGG AGA GGA GAA AAG GTT GTC ATC AAT GTG CCA ATA TTC 624 AAG GAC AAG AAC ACA CCA TCT CCG TTT GTA GAA ACA TTT 663 CCT GAG GAT GAG GAG GCA TCA AAG GCC TCT AAG CCA GAC 702 CAC ATC TAC ATG GAT GCC ATG GGA.TTT GGG ATG GGC AAC 741 TGC TGT CTT CAG GTG ACA TTC CAA GCC TGC AGT ATA TCT 780 GAG GCA AGA TAC CTT TAT GAC CAG TTG GCC ACT ATC TGC 819 CCA ATT GTT ATG GCT TTG AGT GCT GCA TCG CCA TTT TAC 858 CGA GGC TAC GTG TCA GAC ATT GAT TGT CGC TCG GGA GTG 897 ATT TCT GCA TCT GTA GAT GAT AGA ACA CGG GAG GAG AGA 936 GGA CTG GAG CCC CTG AAG AAC AAT CGC TTT AAA ATC AGT 975 AAG TCT CGG TAT GAC TCA ATA GAT AGC TAC CTG TCC AAG 1014 TGT GGA GAG AAG TAC AAT GAC ATC GAC CTG ACC ATC GAC 1053 ACG GAG ATC TAC GAG CAG CTC TAA GAG GAA GGC ATC GAT 1092 CAC CTT CTG GCA CAG CAG GTT GCT CAT CTC TTT ATT AGA 1131 GAC CCA CTG ACC CTT TTT GAA GAG AAA ATT CAT CTG GAT 1170 GAT GCC AAC GAG TCT GAC CAT TTT GAG AAT ATT CAG TCC 1209 ACA AAC TGG CAG ACA ATG AGG TTT AAG CCT CCT CCT CCA 1248 AAC TCA GAT ATT GGA TGG AGA GTA GAG TTC CGA CCA ATG 1287 GAG GTA CAG TTG ACA GAC TTT GAG AAC TCT GCC TAT GTG 1326 GTA TTT GTG GTA CTG CTG ACC AGG GTG ATC CTC TCA TAC 1365 AAA CTA GAC TTC CTC ATT CCA CTG TCC AAG GTT GAC GAG 1404 AAC ATG AAA GTG GCA CAG GAG CGA GAT GCC GTC TTA CAG 1443 GGG ATG TTT TAT TTC AGG AAA GAC ATT TGC AAA GCT GGC 1482 AAC GCC GTG GTG GAT GGG TGT AGC AAG GCC CAG ACC AGC 1521 TCC GAG CCA TCT GCA GAG GAG TAC ACG CTC ATG AGC ATA 1560 GAC ACC ATC ATC AAT GGG AAG GAA GGC GTG TTT CCT GGA 1599 CTC ATC CCC ATT CTG AAC TCC TAC CTT GAA AAC ATG GAA 1638 GTC GAC GTG GAC ACC CGA TGC AGT ATT CTG AAC TAC CTG 1677 AAG CTA ATT AAG AAG AGA GCA TCT GGA GAA CTA ATG ACT 1716 GTT GCC AGG TGG ATG AGA GAG TTT ATT GCA AAC CAT CCT 1755 GAC TAC AAG CAA GAC AGT GTA ATA ACT GAT GAG ATC AAC 1794 TAT AGC CTC ATT TTG AAA TGC AAT CAA ATT GCA AAT GAA 1833 TTG TCT GAA TCT CCAGAG TTACTT GGA TCAGGC TTT AGA 1872 AAA GCG AAG TAC AGT GGA GGT AAA AGC GAC CCT TCA GAC 1911 TAG 1914