JPH06125768A - Manifestation of foreign protein by yeast and culture improved in production - Google Patents

Abstract

PURPOSE:To improve the productivity in comparison with the conventional culture method by >= two times even in the case of a strain in which a plasmid selected from YEp-, YIp- and YCp-type plasmids each bonded to a heterogene in the presence of a promoter of a constituting enzyme is transduced by designing a selection medium in manifestation of the heteroproteins and a productivity- improved culture method in the presence of a yeast. CONSTITUTION:A transformant yeast is subjected to a productivity-improved culture in a selection culture medium prepared by using yeast nitrogen base w/o amino acids and glucose as the main agents and admixing essential nutrients therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION In the present invention, the nutrient medium is Y
PD medium. The present invention relates to a culture method for increasing expression and production of a heterologous protein by yeast, comprising claims 1 to 5, claim 1 relates to a temperature shift culture method, claim 2 relates to a low temperature preculture method, and claim 3 Claims 1 and 2 relate to the specification of a host that highly produces the heterologous protein, claim 4 relates to the specification of a promoter that expresses and produces the heterologous protein of the inventions 1 and 2, and claim 5 relates to the claim 1. The present invention relates to the identification of a yeast vector that expresses and produces the heterologous protein of the second aspect of the present invention, which contributes to the enzyme industry by increasing the production amount several times as compared with the conventional culture method.

[0002]

2. Description of the Related Art Conventionally, in the enzyme industry, in order to improve the secretory productivity of transformed strains such as yeast, the medium composition has been studied. However, in the conventional method, it takes a long time to screen the medium and the productivity is limited to only a few percent improvement. Therefore, a more effective and simple culture method is required.

[0003]

In view of the above situation, the present inventors have studied as a problem to be solved to develop a simple culture method that improves productivity several times. This problem to be solved is also an object of the present invention.

[0004]

[Means for Solving the Problems] First, the present inventors have developed a yeast expression vector (YEp having a promoter for a constitutive enzyme).
Type) and the α-amylase (hereinafter referred to as takaamylase A) cDNA of Aspergillus oryzae and human lysozyme cDNA.
Plasmids were separately ligated with each other and transformed into yeast. This transformant is pre-cultured in a selective medium, the cell pellet is transplanted to a non-selective medium, shake-cultured at a low temperature, and further cultured at an appropriate temperature, so that both Taka-amylase A and human lysozyme can be used for a long time. It was found that the productivity is increased as compared with the conventional culture method of shaking culture.

Further, a plasmid in which a takapyl amylase cDNA is ligated to a YIp type vector or a plasmid in which a human lysozyme cDNA is ligated to a YCp type vector is introduced into yeast, and the obtained transformant is subjected to the same temperature shift culture method as described above. When the secretory production of a heterologous protein was performed, the production amount increased. Using a strain transduced with any of the YEp type, YIp type and YCp type plasmids in which a heterologous gene is connected under the control of a promoter of a constitutive enzyme, or the equivalent type plasmid, the productivity is at least 2 as compared with the conventional culture method. Doubled.

The present invention is based on the above-mentioned research results. The invention of claim 1 pre-incubates each of the transformed strains until it grows sufficiently in a selective medium, and the bacterial cell pellet is used as a nutrient medium. The present invention according to claim 2 relates to a temperature shift culture method, which comprises performing shaking culture at a temperature at which yeast is well grown after transplanting and culturing at low temperature. After pre-culturing at low temperature until it grows well, transplant the cell pellet into nutrient medium,
The invention according to claim 3 relates to a low temperature pre-culturing method, which comprises shaking culture at a temperature higher than that of the selective medium,
The invention of claim 2 relates to the identification of a host that highly produces a heterologous protein, the claim of claim 4 relates to the identification of a promoter that expresses and produces the heterologous protein of the invention of claims 1 and 2, and the invention of claim 5 claims The present invention relates to the identification of a yeast vector that expresses and produces a heterologous protein of the inventions of items 1 and 2.

The yeast expression vector used in the present invention has a size of 2 μm.
It is either YEp type having DNA, YIp type integrating into chromosome, YCp type having yeast centromere DNA, or the same effect type. The promoter for expressing a heterologous gene includes a promoter for alcohol dehydrogenase (ADH1) , which is a constitutively expressed enzyme, and a glyceraldehyde-3-phosphate dehydrogenase (G
AP) promoter. Yeast Saccharomyces cerevisiae was used as a host.

[0008]

As described in the following Examples (1) to (3), the present invention provides a method for culturing a heterologous protein expression and production by yeast according to the inventions of Claims 1 and 2. In addition, the inventions of claims 3 to 5 enhance the actions of the inventions of claims 1 and 2.

[0009]

[Example] The selective medium of this example was prepared by using plasmids A to C,
For strains transduced with E to F, 0.67% yeast
Itrogen base w / o amino acid, 2% glucose
As the main ingredient, 20 mg / l histidine, 20 mg / l uracil, 30
Add mg / l leucine, 20 mg / l adenine, 30 mg / l lysine
It is assumed to have been added. Also, plasmid D was transduced
For strains, instead of uracil, 20 mg / l tryptophan
The fan was added. Plasma for heterologous protein production
Preparation of plasmids: Examples of plasmid A to plasmid F preparation methods
To do. The transformation of these into yeast is carried out by the method of Ito et al.
(J. Ba-cteriol.,153, 163 (1983))
I started. For the produced Taka-amylase A, Ada
chi's method (J. Ferme-nt.Technol.,32, 43
(1954)).
For the method of Suzuki et al.Mol.Gen.Genet.,
219, 58 (1989)) for measuring lysozyme activity
Then, the amount of protein produced was calculated.

◎ Method for preparing plasmid A: 2 μm DN
A, ADH1 promoter, CYC1 terminator and yeast vector pYc having TRP1 as a selectable marker
DE-1 is digested with Eco RI and then dephosphorylated with alkaline phosphatase. Taka amylase cD
An approximately 1.8 kb Eco RI fragment containing NA was ligated in the same direction as the above promoter to prepare a yeast expression plasmid pYTA-1. FIG. 1 is a schematic diagram of the above-described preparation of plasmid A.

◎ Method for preparing plasmid B: Similar to the method for preparing plasmid A, the yeast vector pYcDE-1 was prepared.
Human lysozyme cDNA approximately 0.5 kb at Eco RI site
The Eco RI fragment of was ligated to prepare pYHA-1.
FIG. 2 is a schematic diagram of the above-described preparation of plasmid B.

◎ Method for preparing plasmid C: TRP1
After digesting pTRP11 carrying the gene with Bam HI, dephosphorylation is performed with alkaline phosphatase. P to this
Connecting the fragment of about 3.4kb was excised from YTA-1 with Bam HI (including ADH1 promoter and Taka-amylase cDNA), yeast chromosomal integrative plasmid pTAT
-11 was produced. FIG. 3 is a schematic diagram of the above-described preparation of plasmid C.

◎ Method for preparing plasmid D: CEN
6. The yeast centromere vector pRS316-AC having ADH1 promoter, CYC1 terminator and URA3 as a selection marker is digested with Eco RI and then dephosphorylated with alkaline phosphatase. A 0.5 kb Eco RI fragment containing human lysozyme cDNA was ligated to the promoter so that the direction thereof was the same as that of the above promoter to prepare yeast centromere plasmid pCHA-1. FIG. 4 is a schematic diagram of the above-described preparation of plasmid D.

◎ Method for preparing plasmid E: 2 μmD
Yeast vector pG-3 having NA, GAP promoter, PGK terminator and TRP1 as a selectable marker
Is digested with Bam HI and then blunt-ended. A fragment of about 1.8 kb containing the blunt-ended Taka amylase cDNA was ligated to the promoter so that the promoter and the direction thereof were aligned with each other to prepare a yeast expression plasmid pYGTAA. FIG. 5 is a schematic diagram of the above-described preparation of plasmid E.

◎ Method for constructing plasmid F: Similar to the method for constructing plasmid E, Bam H of yeast vector pG-3
The blunt-ended version of I was ligated to a blunt-ended human lysozyme cDNA fragment of about 0.5 kb to obtain pYGHLY.
Was produced. FIG. 6 is a schematic diagram of the above-described preparation of plasmid F.

Preparation of Yeast Transformant for Producing Heterologous Protein Takaamylase A and the above-mentioned plasmids A to F for secreting and producing human lysozyme were transformed by the method of Ito et al. That is, yeast (YPH250) was shake-cultured at 30 ° C. in 10 ml of a nutrient medium (1% yeast extract, 2% polypeptone, 2% glucose) and collected by centrifugation in the logarithmic growth phase. After washing with TE buffer, the cells were suspended in the same buffer at a concentration of 2 × 10 ⁷ cells / ml. This 0.5 ml
Was transferred to a small test tube, an equal volume of 0.2 M lithium acetate solution was added, and the mixture was shaken at 30 ° C. for 30 to 60 minutes. From this, 0.1 ml was transferred to a 1.5 ml Eppendorf tube, 5 μl (2 μg / μl) of a plasmid DNA solution was added, and static culture was carried out at 30 ° C. for 30 minutes. Next, sterilized 70%
150 μl of PEG-4000 was added and mixed well. Three
After standing at 0 ° C for 60 minutes, the Eppendorf tube was left standing at 47 ° C in a constant temperature bath for 10 minutes, and then the cells were immediately cooled to room temperature, washed with sterilized water, and transformed into a selective medium. Obtained. Restriction enzyme Stu for plasmid C
10 μl of a linear DNA solution treated with I (5 μg /
μl) was subjected to the transformation described above.

Example (1) Culture Method for Increasing Production of Heterologous Protein by Yeast Transformant The transformants introduced with the plasmids E and F were precultured in 10 ml of a selective medium at 30 ° C. for 24 hours and then collected. The obtained bacterial cell pellet was transplanted to a nutrient medium, and the pellet was placed at 10 to 30 ° C for 4 hours.
Shaking culture was carried out for 8 hours at 30 ° C. for 40 to 50 hours, preferably for 48 hours. A culture supernatant was obtained by centrifuging the culture solution, and α-amylase activity and lysozyme activity were measured for each, and the amount of protein produced was examined. FIG. 7 is a graph showing the relationship between the production amount of takaamylase and the production amount of human lysozyme and the temperature in low temperature culture.

Example (2) Production of heterologous protein using temperature shift culturing method and low temperature pre-culturing method The transformants introduced with the plasmids E and F were pre-cultured in a selective medium (10 ml) at 30 ° C. until sufficient growth. After collecting the cells, transplanting the obtained bacterial cell pellets into a nutrient medium, and then 1
The cells were cultured at 5 ° C for 40 to 50 hours, preferably 48 hours, and further at 30 ° C for 40 to 50 hours, preferably 48 hours with shaking. (Temperature shift culture method: see claim 1) The transformant was precultured in 10 ml of selective medium at 15 ° C for 3 days or for 1 day until sufficient growth, and then the cells were collected. The obtained bacterial cell pellet was transplanted to a nutrient medium and then shake-cultured at 30 ° C. for 90 to 100 hours, preferably 96 hours. (Cold preculture method: see claim 2)

A culture supernatant was obtained by centrifuging the culture solution of each of the above two culture methods.
-Amylase activity and lysozyme activity were measured to examine the amount of protein produced. Here, as a control, plasmid A
The culture supernatant obtained by pre-culturing the B and B transformants and culturing at 30 ° C. for 96 hours was used. Table 1 shows the production of heterologous proteins using the temperature shift culture method and the low temperature preculture method.

[Table 1]

Example (3) Effect of Yeast Expression Vector on Production of Heterologous Protein Using Temperature Shift Culture Method A transformant containing plasmids A to F was obtained in a selective medium according to the temperature shift culture method described above. Α- of the obtained culture supernatant
The amylase activity and lysozyme activity were measured and the production amount was investigated. Here, as a control, a culture supernatant obtained by pre-culturing each transformant at 30 ° C. and then culturing at 30 ° C. for 90 to 100 hours, preferably 96 hours was used. Table 2 shows the effect of yeast expression vectors on the production of heterologous proteins using the temperature shift culture method.

[Table 2]

[0021]

EFFECTS OF THE INVENTION The inventions of claims 1 to 5 of the present invention contribute to the expression of a heterologous protein and the increase of the production amount by a yeast,
Alternatively, the contribution effect is improved, and there is a remarkable effect that the production amount at least twice as large as the production amount by the conventional method can be mentioned.

[Brief description of drawings]

FIG. 1 Schematic diagram of plasmid A production

FIG. 2 Schematic diagram of plasmid B production

[Fig. 3] Schematic diagram of plasmid C production

FIG. 4 Schematic diagram of plasmid D production

FIG. 5: Schematic diagram of plasmid E production

FIG. 6 Schematic diagram of plasmid F production

FIG. 7 is a graph showing the relationship between the production amount of takaamylase and the production amount of human lysozyme in Example (1) and the temperature at the time of low temperature culture.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication C12N 15/62 // C12N 15/56 (C12N 1/16 C12R 1: 865) (C12N 9/30 (C12R 1: 865) (C12N 9/36 C12R 1: 865) (72) Inventor Katsuya Gomi 2-6-30, Takinogawa, Kita-ku, Tokyo Metropolitan Tax Bureau Brewing Test Center (72) Inventor Yamamoto So 19 19 Showa-cho, Anjo City, Aichi Prefecture No. 10 Shin-Nippon Chemical Industry Co., Ltd. (72) Inventor Nao Nagashima 19-10 Showa-cho, Anjo City, Aichi Prefecture Shin-Nippon Chemical Industry Co., Ltd.

Claims (5)

[Claims] 1. A transformant strain is pre-cultured at a suitable temperature until it grows sufficiently in a selective medium (hereinafter simply referred to as selective medium) in which yeast nitrogen base w / o amino acid and glucose are the main ingredients, and required nutrients are added to this. Then, the cell pellet is transplanted to a nutrient medium, cultivated at a low temperature, and then shake culturing is performed at a temperature at which yeast grows well, which is a temperature shift culturing method. 2. The transformant strain is pre-cultured at a low temperature until it grows sufficiently in a selection medium, and then the cell pellet is transplanted to a nutrient medium and shake-cultured at a temperature higher than the pre-culture in the selection medium. Characterizing low temperature preculture method. 3. The temperature shift culturing method according to claim 1 or the low temperature pre-culturing method according to claim 2, wherein the host that highly produces the heterologous protein is yeast in a microorganism. 4. The temperature shift culture method according to claim 1 or the low temperature preculture method according to claim 2, wherein the promoter that expresses and produces the heterologous protein is a promoter of an enzyme that is constitutively expressed. 5. A yeast vector for expressing and producing a heterologous protein in yeast, YEp having 2 μm DNA.
The temperature-shift culture method according to claim 1 or the low-temperature preculture method according to claim 2, wherein the type is YIp type or YCp type having yeast centromere DNA to be integrated into the chromosome, or the same-effect type.