天蓝色链霉菌中S-adenosylmethionine依赖性甲基转移酶同源基因sco1162调控孢子发育及抗生素合成

A S-adenosylmethionine Dependent Methyltransferase Homologous Gene,sco1162,Regulates Spore Development and Antibiotic Synthesis in Streptomyces coelicolor

利用大肠杆菌-链霉菌穿梭质粒pDZY101携带的转座子Tn101随机插入到天蓝色链霉菌(Streptomyces coelicolor)M145构建的插入突变库,从中分离到一株孢子色素及抗生素合成明显发生变化的菌株BZ100.测序发现,该突变株中Tn101插入到了链霉菌的sco1162基因中.序列分析表明,该基因编码S腺苷甲硫氨酸(S-adenosylmethionine,SAM)依赖的甲基转移酶.为了验证该插入突变与表型的对应关系,构建了能在突变菌株中表达sco1162基因的互补质粒pFDZ16-1162,将该质粒转化突变株后,突变菌株的孢子形态和抗生素合成水平得到完全恢复.

Using Escherichia coli-Streptomyces shuttle plasmid pDZY101 which carried transposon Tn101,an insertion mutant library in Streptomyces coelicolor M145 was constructed.This library contained a strain with significant changes in spore pigment and antibiotic synthesis,named BZ100.Sequence analysis showed that transposon Tn101 inserted in a methyltransferase homologous gene sco1162,which encodes a SAM（S-adenosylmethionine） dependent methyltransferase.To verify the correlation between the insertion mutant genotype and phenotypes,a plasmid named pFDZ16-1162 with itself promoter to drive the expression of sco1162 in Streptomyces was constructed.After transforming pFDZ16-1162 back into mutant lines,the mutant phenotype was rescued and both the spore development and antibiotic synthesis get recovered.This result confirmed that the correlation between the insertion mutated genotype and the phenotype,therefore,it suggests that sco1162 gene plays an important role in both the spore development and secondary metabolism of Streptomyces.