Jin T, Inouye M
Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, NJ 08854-5635, USA.
FEMS Microbiol Lett. 1995 Nov 15;133(3):225-31. doi: 10.1111/j.1574-6968.1995.tb07889.x.
Osmoregulation of the porin genes, ompF and ompC of Escherichia coli, occurs at the level of transcription through the action of EnvZ and OmpR proteins as well as at the level of translation through micF antisense RNA. In this study, we used a genetic screening approach to identify new genes which interfere with the expression of ompC or ompF. Using an E. coli genomic library in pUC19, we identified three clones whose products altered expression of ompC and ompF in response to medium osmolarity. One clone carrying the secB gene was found to block ompC and inhibit ompF expression. One clone carrying gcvA, a transcriptional regulator for the gvcA operon, was found to block ompF expression at high osmolarity and elevate ompC expression at low osmolarity. One clone carrying rbsR, a repressor for the rbs operon, was found to block ompF expression at both low and high osmolarities and elevate ompC expression at low osmolarity. These results suggest that ompF and ompC expression is associated with other physiological regulating systems in addition to osmoregulation.
大肠杆菌孔蛋白基因ompF和ompC的渗透调节，通过EnvZ和OmpR蛋白的作用在转录水平发生，同时也通过micF反义RNA在翻译水平发生。在本研究中，我们采用遗传筛选方法来鉴定干扰ompC或ompF表达的新基因。利用pUC19中的大肠杆菌基因组文库，我们鉴定出三个克隆，其产物可响应培养基渗透压改变ompC和ompF的表达。发现一个携带secB基因的克隆可阻断ompC并抑制ompF表达。发现一个携带gvcA操纵子转录调节因子gcvA的克隆在高渗透压下阻断ompF表达，在低渗透压下提高ompC表达。发现一个携带rbs操纵子阻遏物rbsR的克隆在低渗透压和高渗透压下均阻断ompF表达，在低渗透压下提高ompC表达。这些结果表明，ompF和ompC的表达除了与渗透调节相关外，还与其他生理调节系统有关。
