METHOD FOR THE PRODUCTION OF SALMON GROWTH HORMONE USING A SYNTHETIC GENE

Abstract: High protein content feed or hormonal steroids have been added to fish feed in order to elevate the efficiency of the feed. However, the steroids remain in the fish and may be detrimental to those who eat the fish. The invention relates to a method for the production of salmon growth hormone, which enhances the efficiency of the feed without the above side effects, using a synthetic gene in yeast or E.coli. It has been found that salmon growth hormone may be produced economically and in bulk in yeast or E.coli by gene manipulation technology.

Description: METHOD FOR THE PRODUCTION OF SALMON GROWTH HORMONE USING A SYNTHETIC GENE BACKGROUND OF THE INVENTION The present invention relates to a method for the produc¬ tion of salmon growth hormone using a synthetic gene in yeast or E.coli. 10 Up to now, high protein content feed or hormonal steroids have been added to the feed used at fish farms in order to elevate the efficiency of the feed. It has been found in developed nations including the U.S.A. that the steroid, » 1.5 however, is not metabolized iπsnediately but remains in the fish for a long time after ingestion and then the presence of the steroid is detrimental to those who eat the fish and the prohibition of the use of these steroids has been increased. On the other hand, because the salmon growth hormone does not remain inside the body after ingestion and because it. has a species-specificity, as it is a protein of salmon itself, it is the most desirable material capable of increasing ^ the efficiency of feed. The present inventors have discovered that the salmon growth hormone may be produced economically and in bulk in yeast, or E.coli by gene manipulation technology. SUtΦiARY OF"THE INVENTION One object of the present invention is to provide a method for the production of salmon growth hormone using yeast as a host for expression vectors. The other object of the present invention is to provide a method for the production of salmon growth hormone using E.coli as a host for expression vectors. Firstly, the method for the production of salmon growth hormone using yeast as a host for expression vectors comprises : (a) synthesizing oligonucleotides having Xbal, Hind ill and Sail restriction sites for manipulation of the salmon. rowth 5 hormone gene, (b) ligating one fragment with the Xbal/Hindlll sites and the other fragment with the Hindlll/Sall sites according to the ligation strategy to plasmid, pUC18, respec¬ tively, (c) religating the two cloned fragments to plasmid, pUC18 to get a salmon growth hormone gene lacking a portion of 10 the N-terminus, (d) inserting the partial salmon growth hormone gene and N-terminal synthetic adaptor to a plasmid consisting of a promoter and a terminator to make a cassette of promoter-salmon growth hormone with an N-terminal synthetic adaptor-terminator, (e) inserting the cassette to an E.coli- Iδ. -yeast shuttle vector for expression in yeast and (f) expressing the resultant vector in yeast cells. The N-termirtal s^Tithetic adaptor is the f llowing nucieotide sequence having Ncσi site and Xbai site: Ncol site Xbai site The yeast expression vector is named as pϋl/1-SGH containing- the cassette comprising promoter-salmon growth hormone gene with an N-terminal synthetic adaptor-terminator, a complete 2 micron, a Leu 2d gene and an origin of reolication. Secondly, the method for the production of salmon growth hormone in E.coli as a host comprises : (a) synthesizing oligonucleotides having Xbal,Hindlli and Sail restriction sites for manipulation of the salmon growth hormone sene, Cb) ligating the N-terminal fragment with the Xbal/Hindlli sites and the C-terminal fragment with the Hindlll/Sall sixes according to the ligation strategy to plasmid, pUCIS, respectively, (c) religating the two cloned frasnents to plasmid, pUC18, to get a salmon growth hormone gene lacking a portion of the N-terminus, (d) inserting the partial salmon growth hormone gene and N-terminal synthetic adaptor to plasmid, pBR322, (e) ligating the obtained salmon growth hormone gene and a synthetic adaptor to the expression vector with trp promoter and (f) expressing the resultant vector with the synthetic adaptor in E.coli. The N-terminal synthetic adaptor for E.coli expression vector is the following nucleotide sequence which has Ndel and Xbal sites and comprises an upper strand of 38 mer (5' -T ATG ATC GAA AAT CAG CGT TTA TTC AAC ATT GCA ATT T-3' ) and a lower strand of 40 mer (3' -AC TAG CTT TTA GTC GCA AAT AAG TTG TAA CGT CAA AGA TC-5' ) . » The other synthetic adaptor for a partial promoter sequence is the following nucleotide sequence which has Hpal and Ndel sites and comprises an upper strand of 36 mer (5' -AAC TAG TAC GCA ACT TCA CGT AAA AAG GGT AAT ACA -3' ) and a lower strand of 38 mer (3'-TTG ATC ATG CGT TCA AG-T GCA TTT TTC CCA TTA TGT AT-5 1 ) For a better understanding of the invention, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated. BRIEF DESCRIPTION OF THE DRAWINGS Fig.l shows synthetic oligonucleotides corresponding to a saljnon growth hormone gene and represented by a base sequence from, the 5'-end to the 3'-end. Fig.2 is a ligation strategy of oligonucleotides in accordance with Fig.l. Fig.3 is a schematic cloning process of synthetic oligonucleotides to the plasmid, pUC18. Fig.4 is the base sequence and putative amino acid sequence of confirmed salmon growth hormone gene. Fig.5 is a cloning process into a yeast expression vector (pCl/1) for producing salmon growth hormone in yeast. Fig.6 is a cloning strategy for expression of salmon growth hormone gene in E.coli. Fig.7 are the results confirmed by SDS-polyacryl amide gel electrophoresis of salmon growth hormone produced in yeast cells. Fig.8 are the results confirmed by SDS-polyacryl amide gel electrophoresis of salmon growth hormone produced in E.coli. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT The present inventors selected the base sequence of salmon growth hormone with amino acid ccdons preferentially used by yeast cells, based upon the amino acid sequence of salmon growth hormone, reported by Sekine et al.[Proc. Natl.Acad. Sci,USA 82(1985) 4308] and the complete gene of mature sal on growth hormone was chemically synthesized using a DNA synthesizer(Applied Biosystem Model 380B, USA) accordixig to phosphoramidate's method. The synthetic oligonucleotides are ligated and inserted to a vector for E.coli,pUC18[Norrander, J . et al. Gene 36 (1983) 101] to produce pSGH(533) comprising an Xbal/Sall restriction fragment of 533 bp, which does not have an N-terminal region of the complete salmon growth hormone gene (Refer to Fig.3). Firstly, a method for the production of salmon growth hormone in yeast cells is as follows; The clone comprising Q the complete salmon growth hormone gene with a synthetic adaptor is ligated between the Ncol site and Sail site of a vector having a promoter and a terminator gene,pBS100 [Yeast 2.72 (1986) ; Chiron Corp.Emeryville,CA94608, U.S.A.] to express in yeast, wherein the adaptor is comprised of an 5 Ncol restriction site, an initiation codon and some amino acid codons corresponding to the N-terminal region of salmon growth hormone. The obtained vector is pBS-SGH. The vector pBS-SGH was treated with BamHI restriction enzyme to separate the BamHI fragment(about 2.7Kb) comprising 0 promoter, salmon growth hormone gene and terminator. The BamHI fragment is inserted into the BamHI restriction site of a yeast expression vector,pCl/1, which is automatically replicated in E.coli and yeast(ATCC 37115; Brake et al. Proc.Natl.Acad. Sci USA 81(1984), 4642] to produce pCl/1-SGH (Refer to Fig.5) . The above yeast expression vector cloned to yeast strain, DC04 [Broach,J.R. & Hicks,J.B. Cell 21, 501(1980); Yeast Genetic Stock Center, University of California, Berkeley, U. S. A. ] by means of Hinnen et al.'s method. The transformed yeast cell was cultured in YEH) medium comprising 2% glucose as in Example 4 for 48 hrs. When the concentra¬ tion of glucose is exhausted, salmon growth hormone is induced automatically and salmon growth hormone about 50mg per liter of culture at ODβso = 15 was produced. Secondly, a method for the production of salmon growth hormone in E.coli is as follows; The Xbal/Sall restriction fragment and an N-terminal synthetic adaptor designed as codons, in which the ATG region, the initiation codon, may be cut with Ndel restriction enzyme and which is preferentially used in E.coli r are finally ligated to a vector for E.coli, pBR322 (Refer to Example 3). The Ndel/Sall restriction fragment of 571 base pairs comprising the complete growth hormone gene with synthetic oligonucleotide in which the bases between the SD (Shine Dalgarno) sequence and ATG, an initiation codon, are suitably arranged in order not to produce a secondary str¬ ucture of mRNA was ligated to a vector for expression in E.coli, ptrp 322[Russel,D.R. & Bennet,G.N. Gene 20,23 (1981); Efaarmacia Inc., Picataway, N.J.08854, U.S.A.], cut with Hpal and Sail restriction enzymes. After that, the resultant vector (ptrp322HSGH) was cloned to E.coli 3110 (ATCC 27325) (Refer to Example 3). The salmon growth hormone gene was expressed in E.coli by using IAA (Indole acrylic acid) as an inducing agent in M9 medium and growth hormone was identified by means of SDS-polyacrylamide gel electrophoresis (Refer to Example 5) . The invention is illustrated by the following Examples, without them limiting its range. Example 1: Ligation and cloning of synthetic oligo- nucleotides for salmon .growth hormone gene In order to obtain a complete salmon growth hormone gene from the synthetic oligonucleotides having the sequences of Fig.l, the ligation strategy of Fig.2 and vector pUC18 were used. Each oligonucleotide(U8-U14/L9-L14) corresponding to the C-terminal Hindlll and Sail restriction fragments of the salmon growth hormone gene was taken the amount of 0.05 QD260 respectively, and then separately dried. Four units of T4 polynucleotide kinase are added to the total volume of 30 J- 1 1 in the presence of 50mM Tris-HCl (pH 7.5), ImM ATP, ImM DTT and lOmM Clϊ and they axe reacted for 30 minutes in order to phosphorylate the 5'-end residue of the oligonucleotides. After the oligonucleotides are pooled and treated with an equal volume of phenol and chloroform mixture (24:1, v/v) , they are precipitated with ethanol. The precipitates were dissolved in 53.M 1 of a buffer solution comprising 60mM Tris-HCl (pH 7.5), ImM DTT and lOmM MgCl 2 . The solution was placed in 95 3 C water bath and kept at room temperature for 6 hrs until the temperature drops to room temperature. Twenty units of T4 DNA ligase and 5 y 1 of 10 mM ATP were added herein and ligation reaction was done at room temperature for 10 mins. This reaction solution was treated with phenol and chloroform mixture and precipitated with ethanol as described above. Ten units each of Hindlll and Sail restriction enzymes are added to the precipitated in the presence of a buf er solution comprising 60 mM Tris-HCl (pH 7.6) , lOmM MgCl 2 and 100 mM NaCl and reacted at 37'C for 1 hr. After 7% polyacrylamide gel electrophoresis, a band corresponding to 220-300 base pairs is cut from the gel. After electroelution, the precipitates were dissolved in 20 y 1 of distilled water. Three 1 of DNA and 10 ng of a vector, pUC18, cut with Hindlll and Sail restriction enzymes are ligated in the presence of the ligation solution comprising 60 mM Tris-HCl (pH 7.5), 10 mM MgCla, 1 mM ATP and 10 units of T4 DNA ligase at 14 α C for 16 hrs. E.coli M 103[BRL,U.S.A. , Messing,J. Methods in Enzymology, 101, 20 (1983)] competent cell was added to the ligation mixture and transformed according to Hanahan's method [J.Mol.Biol 118, 557(1983)] at 37 °C overnight. The recombinant vector, p3'-SGH was selected from the white clonies according to Birnboim and Doly's method [Nucleic Acid Res.7, 1513 (1979)]. On the other hand, the oligonucleotides(U1-U7/L2-L8) corresponding to the N-terminal Xbal and Hindlll restriction fragments of the synthetic oligonucleotides were ligated by the same method as mentioned above and inserted to pUC18, cut with Xbal and Hindlll restriction enzymes to get p5'-SGH by the method of Fig.3. Finally, the DNA sequences of p3'-SGH and p5'-SGH are confirmed by the method of Sanger's dideoxy chain termination method [Proc. Natl. Acad. Sci. USA 74, 5473, (1977)] (Refer to Fig. 4). The Hindlll/Sall restriction fragment from p3'-SGH and the Xbal/HincLEII restriction fragment from p5 5 -SGH are isolated respectively and ligated to a vector, pUC18, cut with Xbal and Sail restriction enzymes to produce pSGH(533) (Refer to Fig.3). Example 2: Manipulation of synthetic salmon growth hormone gene for expression in yeast cells The 5'-end deficient part of the complete salmon growth hormone gene exists in pSGH(533) and it was synthesized by a DNA synthesizer. In the synthetic adaptor, the Ncol restriction enzyme site, an initiation codon and ccdons corresponding to NH2-terminal 12 amino acids of salmon growth hormone were synthesized by selecting codons preferentially used in yeast; cells (Refer to Fig. 5). The process of cloning is as follows; pSGH{533) was treated with Xbal and Sail restriction enzymes to obtain a restriction fragment corresponding to 533 bp and the fragment was separated through agarose electrophoresis. The synthetic adaptor was phosphorylated with T4 polynucleotide kinase as described previously. One y 1 of the phosphorylated adaptor reactant, 3 1(30 ng) of the Xbal/Sail fragment of growth hormone gene and 1 __ ■ 1 (7 ng) of vector pBSlOO (Yeast 2, 72(1986)) cut with Ncol and Sail restriction enzymes were mixed together in the presence of 2 y 1 of 10 mM ATP, 2 . I of 10-fold concentrated ligation reaction buffer solution, 1 y 1 of ligase and 10 y 1 of distilled water and incubated at 14 " C for 16 hrs. As mentioned in Example 1, the ligation mixture was cloned to E.coli cell HB 101 (ATCC 33694) and a recombinant vector, pBS-SGH comprising a promoter, the complete salmon growth hormone gene and a terminator for expression in yeast was obtained. The above mentioned vector, pBSlOO, contains the hybrid promoter of alcohol dehydrogenase II promoter and glyceraldehyde 3'-phosphate dehydrogenase promoter. The vector, pBS-SGH was treated with BamHI restriction enzyme to separate the BamHI restriction fragment of about 2,700 bp, comprising a hybrid promoter, the salmon growth hormone gene and the terminator of glyceraldehyde 3'- phosphate dehydrogenase. The BamHI restriction fragment was inserted into the BamHI restriction site of the vector for yeast expression, pCl/l(ATCC 37115), to obtain pCl/1-SGH (Refer to Fig.5) . Ten y g of pCl/1-SGH gene was cloned to yeast strain DCC4 [Yeast Genetic Stock Center, University of California, Berkeley, U.S.A., Broach, J.R. & Hicks, J.B. Cell 21, 501 (1980)] according to Hinnen's method [Proc. Natl. Acad. Sci. USA 75 (1978), 1929] and plated on agar-plates without leucine, comprising 6.7g of Yeast Nitrogen Base without amino acids, 182 g of sorbitol 2% glucose, 0.25 g of Leu-supplements and 20 g of Bactoagar per liter. Recombinant clones containg salmone growth hormone gene were shown after 3 to 5 days of transformation. Example 3: Manipulation of complete salmon growth hormone gene to an E.coli expression vector DNA sequences corresponding to NH2-terminal of the complete salmone growth hormone gene were selected codons preferentially used in E.coli. Ndel and Xbal adaptor of an upper strand of 38mer (5'-T ATG ATC GAA AAT CAG CGT TTA TTC AAC ATT 1 GCA GTT T-3' ) and a lower strand of 40 mer (3'-AC TAG CTT TTA GTC GCA AAT AAG TTG TAA CGT CAA AGA TC-5' ) were synthesized. The Xbal/Sail fragment of 533 base pairs separated from pSGH and the synthetic adaptor was inserted to a vector for E.coli, pBR322[ATCC 37017], cut with Ndel and Sail restriction enzymes to obtain pBR SGH clone comprising the complete salmon growth hormone gene (Refer to Fig. 6). An expression vector with trp-promoter, ptrp322 cut with Hpal and Sail restriction enzymes. The fragment of 2.3 Kb was electroeluted through agarose gel electro¬ phoresis and precipitated with ethanol. The pBR SGH described above was treated with Ndel and Sail restriction enzymes to obtain a fragment of 571 bp. The synthetic adaptor was designed so that 9 base sequence was present between the SD sequence (5'-AAGG-3' ) of the trp promoter and the initiation codon of the salmon growth hormone gene and the mRNA corresponding to the region does not form a secondary structure. An adaptor of an upper strand of 36 mer (5'-AAC TAG TAC GCA AGT TCA CGT AAA AAG GGT AAT ACA-3* ) and a lower strand of 38 mer (3'-TTG ATC ATG CGT TCA AGT GCA TTT TTC CCA TTA TGT AT-5' ) was designed so as that both ends are adapted to the Hpal and Ndel restriciton sites. The Ndel/Sail restriction fragment of 571 bp and the synthetic adaptor were ligated to ptrp322, cut with Hpal and Sail restriciton enzymes. E.coli HBIOKATCC 33694) was transformed to obtain a recombinant clone containing the salmon growth hormone gene and the trp-promoter, which is called ptrp 322 HSGH (Refer to Fig.6). It is again transformed into a host for expression in E.coli, W3110(ATCC 27325). Example 4: Cultivation for producing salmon growth hormone in yeast cells and its identification Each 3 ml of yeast cells transformed with vector pCl/1-SGH was cultured in a culture medium without leucine (6.7 g of Yeast Nitrogen Base without amino acids,0.25 g of Leu-supplements and 6 % glucose per liter of culture medium) at 30 ° C for 24 hrs. YEPD culture medium(100ml) comprising 2% peptone, 1% yeast extract and 2% glucose was inoculated with 1 ml of the overnight culture and cultured at 30 ° C for 24hrs. 40ml of ethanol was added thereto and the solution was further cultured for 24 hrs. The resultant ODβso was about 40. That ODβso per ml of 10 was taken and centrifuged. It was dissolved in 400 y 1 of a buffer solution containing 10 M Tris-HCl (pH 7.5), 1 mM EDTA,2 M phenyl methyl sulfonyl fluoride{PMSF) and 8 M urea and glass beads with a diameter of 0.45 mm with the same volume were added thereto and shaken vigorously. After rupturing the cell wall and allowing the salmon growth hormone to elute into the buffer solution, 4 1 of eluted solution was examined by electrophoresis on 12.5% SDS polyacrylamide gel. The results are represented in Fig. ; Lane 1 represents standard M.W. of protein from Bio-Rad company. Lane 2 represents all the proteins of yeast cell trans¬ formed with vector pCl/1 without the salmon growth hormone gene. Lane 3 represents all the proteins of yeast cell transformed with vector pCl/1-SGH with the salmon growth hormone gene. As shown in lane 3 of Fig. , by the gel scanning, the salmon growth hormone appears at a band about 22 Kd in an amount corresponding to 5% of the total proteins. By peptide sequencing of purified salmone growth hormone, it is a mature salmon growth hormone which isoleucine of initiation codon. Example 5: High-level expression of salmon growth hormone gene in an E.coli W3110 and confir¬ mation by SDS-polyacrylamide gel electro- phoresis W3110 with the expression vector, ptrp 322 HSGH was cultured in LB medium containing 40 y g/ml of ampicillin at 37 ° C for 16 hrs.and inoculated to M9 medium. When ODβso reached 0.5, 60 y g/ l of IAA (Indole Acrylic Acid) was added and further cultured at 37 ° C for 24 hrs. The cultured bacteria corresponding to ODβso of 1.0 was centrifuged and dissolved in 100 y 1 of Laemmli sample buffer [Laemmli D.K. (1970), Nature 227,680]. The solution was heated at 100 ° C for 5 mins. and then 10 y 1 of it was applied to 12.5 % SDS polyacrylamide gel electrophoresis. The results are represented in Fig.8; Lane 1 represents BRL low molecular weight markers. Lanes 2-9 represent the results of strain W3110 with the salmon growth hormone gene (ptrp 322 HSGH) induced by LAA. Lanes 10-13 represent the results of strain W3110 without salmon growth hormone gene (ptrp 322) induced by IAA. As shown in Fig.8, a band of 22 Ed which can not be seen in ptrp322-W3110 without salmon growth hormone gene appears in ptrp322 SGH-W3110 in an amount of more than 20 % of total proteins of E.coli. M9 medium comprises 40mM K.2HPO , 22mM KH2PO-4, 8.5mtf NaCl, 18.7mM NH4CI, ImM MgS0 4 , 0.1m CaCl 2 , 10 y g/ml Vit Bi, 0.4 % Casamino acid, 1 % glucose and 40 y g/ml of ampicillin.

Claims: CLAIMS 1. A method for the procuction of salmon growth hormone, comprising (a) synthesizing oligonucleotides having Xbal, Hindlll and Sail restriction sites according to the amino acid sequence of salmon growth hormone, (b) ligating one fragment with Xbal/Hindlll and the other fragment with Hindlll/Sall according to the ligation strategy to vectors for E.coli, respectively, (c) ligating the two cloned fragments to the vector for E.coli to make a salmon growth hormone gene lacking a portion of the N-terminus, (d) inserting the partial salmon growth hormone gene and N-terminal synthetic adaptor to a vector for E.coli consisting of a promoter and a terminator to get a cassette of promoter-salmon growth hormone gene terminator, (e) inserting the cassette to an E.coli-yeast shuttle vector for expression in yeast and (f) expressing the resultant vector in yeast cells. 2. A method for the production of salmon growth hormone acco-rding to claim 1, wherein the N-terminal synthetic adaptor is the following nucleotide sequence with Ncol and Xbal restriction sites. 5' 4 CATXJATCGAAAACAAAAGATTGTTCAACATTCtTmTIT + 3' 3' j TAGCTTTTGGTTI ΓAACAAGTTGTAACGACAAAGATC j 5' Ncol site Xbal site 3. A method for the production of salmon growth hormone according to claim 1, wherein the resulting expression vector is the cloned vector (pCl/1-SGH) of a cassette comprising promoter-complete salmon growth hormone gene- terminator. 4. A method for the production of salmon growth hormone according to claim 1, wherein the synthetic adaptor was synthesized by amino acid codons which are preferentially used in yeast. 5. A method for the production of salmon growth hormone, comprising (a)synthesizing oligonucleotides according to the amino acid sequence of salmon growth hormone, (b) ligating two fragments according to the ligation strategy 5 to vectors for E.coli, respectively, (c) religating the two cloned fragments to the vector for E.coli to make a salmon growth hormone gene lacking a portion of the N-terminus, (d) inserting the partial salmon growth hormone gene and N-terminal synthetic adaptor to a vector for E.coli, (e) 10. ligating the obtained salmon growth hormone gene and a synthetic adaptor to an expression vector with a trp promoter, and (f) expressing the resultant vector in E.coli. 6. A method for the production of salmon growth hormone 5 according to claim 5, wherein the synthetic oligonucleotide comprises Xbal, Hindlll and Sail restriction sites. 7. A method for the production of salmon growth hormone according to claim 5, wherein the salmon growth hormone 0 gene lacking a portion of the N-terminus is synthesized by the method in which the N-te_rminal fragment with Xbal/ Hindlll and the C-terminal fragment with Hindlll/Sall ligated by the ligation strategy are respectively cloned to a vector for E.coli, pUC18, comprising Xbal, Hindlll and Sail restriction sites and two cloned fragments cut with Xbal/Hindlll and Hindlll/Sall restriction enzymes, respectively are recloned to the vector for E.coli, pϋC18. 8. A method for the production of salmon growth hormone according to claim 5, wherein the N-terminal synthetic adaptor is nucleotide sequence which has Ndel and Xbal restriction sites and comprises an upper strand of 38 mer (5'-T ATG ATC GAA AAT CAG CGT TTA TTC AAC ATT GCA GTT T-3' ) and a lower strand of 40 mer (3'- AC TAG CTT TTA GTC GCA AAT AAG TTG TAA CGT CAA AGA TC-5' ) . 9. A method for the production of salmon growth hormone according to claim 5, wherein the resultant expression vector was obtained by the method in which the vector for expression with the trp promoter was cut with Hpal and Sail restriction enzymes and the salmon growth hormone with the synthetic adaptor was ligated thereto. 10. A method for the production of salmon growth hormone according to claim 5 or 9, wherein the synthetic adaptor is nucleotide sequence which has Hpal and Ndel restriction sites and comprises an upper strand of 36 mer (5'-AAC TAG TAC GCA AGT TCA CGT AAA AAG GGT AAT ACA-3* ) and a lower strand of 38 mer (3'-TTG ATC ATG CGT TCA AGT GCA TTT TTC CCA TTA TGT AT-5 ' ) .

Inventors: HAN KYU BEOM, JEONG HYEON HO, JO JUNG MYEONG, LEE TAE GYU, LEE TAE HO, LEE YONG BEOM, PARK YEONG WOO, HAN, KYU, BEOM, JEONG, HYEON, HO, JO, JUNG, MYEONG, LEE, TAE, GYU, LEE, TAE, HO, LEE, YONG, BEOM, PARK, YEONG, WOO
Applicants: LUCKY LTD, LUCKY, LTD.
Application year: 1987
Main classification: C12N15
IPC codes: C07K14, C12N15, C12P21, C12R1