Molecular cloning and analysis of requlatory-strucutral genes for arginine biosynthtic pathway in Bacillus amyloliquefaciens

作为与大肠杆菌比较的模式系统，将研究解淀粉芽孢杆菌中arg基因的结构及其分子遗传特性。在大肠杆菌的情况下，除了用于从谷氨酸生物合成精氨酸的argECBH簇之外，其他基因在染色体上没有紧密连锁。它们的表达也受非连锁基因产物argR的调控。虽然在其他微生物中对精氨酸营养缺陷型和精氨酸生物合成的研究很少，但芽孢杆菌中精氨酸基因的分子遗传学仍有待阐明。在闵教授的实验室中，对谷氨酸棒杆菌的argEC基因和arg操纵子进行了克隆和研究。因此，将通过大肠杆菌arg营养缺陷型突变体的互补分析来克隆解淀粉芽孢杆菌中的arg基因。通过核苷酸序列分析，将解淀粉B.amyloliquefaciens染色体中arg操纵子的基因结构和调控与大肠杆菌和棒状杆菌系统进行比较。

As a model system to compare with those of Escherichia coli, the structure of the arg genes and their molecular genetic property in Bacillus amyloliquefaciens will be investigated. In the case of E.coli, other genes except for the argECBH cluster for the biosynthesis of arginine from glutamate are not tightly linked on the chromosome. Their expressions are also requlated by the product of unlinked gene, argR.The structure of the arg genes and the operon in E.coli has been studied by many researchers. Although the study on the arg auxotroph and the biosynthesis of arginine have been done a little in other microorganisms, molecular genetics of arg genes in Bacillus sp.remains to be elucidated. In professor Min's laboratory the argEC genes and the arg operon in Corynebacterium glutamicum has been cloned and studied. Therefore, the arg genes in Bacillus amyloliquefaciens will be cloned by a complementation analysis of E.coli arg auxotropic mutant. After the nucleotide sequence analysis, the gene organization and requlation of the arg operon in the B.amyloliquefaciens chromosome will be compared with those of E.coli and Corynebacterium system.