Cloning and
Overexpression of the Mitomycin C Resistance Gene (mcr) from Streptoverticillium caespitosum
HUANG Jian-Qiang, LU Yong-Tao, JIANG Wei-Hong, ZHANG Jing,
ZHAO Guo-Ping, YANG Yun-Liu
( Shanghai Institute of Plant Physiology, the Chinese Academy of Sciences,
Shanghai 200032, China )
Abstract Streptoverticillium
caespitosum ATCC27422 is a major producer of an anti-cancer drug,
mitomycin C. A 6.6 kb DNA fragment containing the mitomycin C resistance gene (mcr)
was isolated from ATCC27422 by shotgun method in order to learn the molecular
mechanism of mitomycin C resistance. By constructing a series of subclones from
this 6.6 kb DNA fragment, the mitomycin C resistance gene was localized on a
3.1 kb DNA fragment. Sequence analysis revealed that the open reading frame of mcr
gene was 1 347 bp in size, encoding 448 amino acids with ATG as initiation
codon and TGA as termination codon. The mcr gene was specifically
expressed under the control of T7 promoter in E.coli, and the
resistance to mitomycin C in the transformant was over 100-fold higher than
that in wild-type strain. The overexpression of mcr gene in E.coli
is very helpful for the further research about the molecular mechanism of drug
resistance.
Key words Streptoverticillium
caespitosum；
mitomycin C resistance gene； cloning； overexpression； resistance level
Received: July 9,
1999 Accepted: August 27, 1999
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