天蓝色链霉菌M145中bldA依赖性突变的遗传定位与分析

Genetic Mapping and Analysis of bldA-dependent Mutation in Streptomyces coelicolor M145

bldA编码天蓝色链霉菌中识别UUA密码的tRNA,大部分菌株的生长不需要bldA功能。M145菌株发生了突变,使bldA成为必需基因。本研究以M145和1258等菌株为亲本,通过3轮杂交筛选构建了菌株LY3,作为遗传定位bldA依赖性(bldA-dependent,bad)突变的亲本之一。用LY3与1258杂交,筛选了217个重组子并鉴定其基因型。对217个重组子的基因型进行遗传分析,将bad突变定位于天蓝色链霉菌染色体SCO3934与SCO4659基因之间的758 kb区域。

bldA encodes the tRNA for the rare UUA codon in Streptomyces coelicolor. Most S. coelicolor strains do not rely on bldA function for their vegetative growth. M145 has been subjected to certain mutation which resulted in the dependence on bldA. In this study, strain LY3 was constructed by several steps of modification or mating in order to localize the bldA-dependent （bad） mutation by genetic mapping. 217 recombinants were selected from the progeny of genetic cross between LY3 and 1258. The genotype of these 217 recombinants was analyzed and scored, which resulted in the localization of bad mutation to the region between SCO3934 and SCO4659 on the 758 kb fragment of the Streptom yces coelicolor chromosome.