• 미생물학회지
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• 제24권4호
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• pp.357-363
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• 1986

Synthesis of threonine and methionine in yeast, Saccharomyces cerevisiae shares a common pathway from aspartate via homoserine. HOM6 gene encodes homoserine dehydrogenase (HSDH) which catalyzes the inter-conversion of beta-aspartate semialdehyde and homoserine. The level of HSDH is under methionine specific control. A recombinant plasmid (pEK1: 13.3kb), containing HOM6 gene, has been isolated and cloned into E. coli by complenemtary transformation of a homoserine auxotrophic yeast strain M-20-20D (hom6, trp1, ura3) to a prototrophic M20-20D/pEK1, using a library of yeast genomic DNA fragments in a yeast centromeric plasmid, YCp50(8.0kb). Isolation of HOM6has been primarily confirmed by retransformation of the original yeast strain M20-20D, using the recombinant plasmid DNA which was extracted from M20-20D/pEK1 and subsequently amplified in E. coli. Eleven cleavage sites in the insery (5.3kb) have been localized through fragment analysis for 8 restriction endonucleases; Bgl II(2 site), Bgl II(1), Cla I(3), Eco RI(1), Hind III(2), Kpn I (1), Pvu II(1) and Xho I(1).

• 한국미생물·생명공학회지
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• 제19권1호
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• pp.31-36
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• 1991

Tn5의 kanamycin 저항성 유전자를 가진 pBEL1 plasmid와 C.glutamicum cryptic plasmid인 pSR1으로 7.5kb의 새로운 plasmid를 만든 후, 이를 pCE1301이라 명명하였다. 이 pCE1301은 PEG1301은 PEG-protoplast법으로 C.glutamicum을 형질전환하였을 때 효율이 약 $3.0\times 10^3$형질전환제/$\mu g$이었으며 SalI과 EcoRI 제한효소 절단부위가 1개씩이었다. 또 Km이 없는 배지에서 25세대까지 안정하게 유지되었으며 B.flavum, E.coli에서 복제되었다. 이 pCE1301을 이용하여 C.glutamicum 의 homoserine dehydrogenase 유전자를 cloning하였다.

• 미생물학회지
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• 제29권3호
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• pp.149-154
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• 1991

Escherichia coli/Corynebacterium glutamicum shuttle vectors, pECCG1 and pECCG2 were constructed by joining a 3.00 kb cryptic plasmid pCB 1 from C. glutamicum and a 3.94 kb plasmid pACYC 177 from E. coli. By trimming unessential parts and introducing mulitiple cloning site into the plasmid pECCG 1, a plasmid pECCG122(5.1kb) was constructed. All the shuttle vectors were stably maintained in C. glutamicum up to about 40 generations irrespective of kanamycin addition in the medium. Threonine operon (homoserine dehydrogenase/homoserine kinase) and dapA gene (dihydrodipicolinate synthetase) of C. glutamicum were cloned into the plasmid pECCG122, and the resultant plasmids were designated pTN31 and pDHDP19, respectively. They were used to study the effect of cloned foreign gene on the stability of the plasmid pECCG122. Plasmids pTN31 and pDHDP19 were segregated rapidly from C. glutamicum when cultured in the medium without kanamycin. In medium with $50\mu${\g/ml} of kanamycin, their segregation rates were much slower than those in medium without kanamycin, but the danamycin addition didn't guarantee the complete maintenance of the plasmids in C. glutamicum.