Regulation of genes involved in uptake of osmoprotectants in Bacillus subtilis

• Main Authors: Chun-Hao Li, 李俊皓
• Other Authors: Gwo-Chyuan Shaw
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/46285105084433313503

碩士 === 國立陽明大學 === 生化暨分子生物研究所 === 100 === High osmolality is one of the factors that may influence the growth of bacteria in its habitats. Many bacteria respond to high-osmolality environments by de novo synthesis of osmoprotectants or by uptake of osmoprotectants from the environment. Previous studies on hyperosmotic stress of Bacillus subtilis were limited to the functions of osmoprotectant uptake systems. In this study, we investigated the transcriptional regulation of the opuB and opuC operons, which are involved in the uptake of choline and some other osmoprotectants. It was found that choline could induce the expression of the opuB operon but not the opuC operon. We also found that yvbF, the gene located immediately upstream of the opuC operon, could regulate the expression of both opuB and opuC operons. The results of EMSA showed that a conserved inverted repeat sequence present in the promoter regions of opuB and opuC was required for YvbF binding, suggesting its role as the YvbF operator. In contrast, inactivation of yvaV, the gene located immediately upstream of the opuB operon, had no significant effect on expression of the opuB and opuC operons. Unexpectedly, the results of EMSA showed that YvaV could bind to the promoter regions of opuB and opuC. A series of deletion of the opuC promoter region has identified a region that was required for osmotic induction of opuC expression. Its corresponding part in the opuB promoter region was found to be required for osmotic induction of opuB expression.