细菌中糖转运相关sRNA 的生理调控功能

Physiological Functions of the SgrS sRNA in Bacteria

当细菌面对较高浓度的葡萄糖时,随着葡萄糖摄入,常会导致菌体内部葡糖-6-磷酸的大量累积。在磷酸糖浓度达到一定阈值时,就会形成一种毒性胁迫从而抑制菌体的代谢与生长。许多细菌则会通过一种小RNA SgrS (sugar transport-related sRNA)的转录后调控作用,来解除这种糖胁迫抑制作用。SgrS在分子伴侣Hfq的协助下,与相应靶mRNA通过碱基互补配对方式结合,对ptsG mRNA和manXYZ mRNA进行负调控以减少糖类摄入,并对yigL mRNA进行正调控以增大糖类排出,从而提高细胞对糖胁迫的耐受性。与一般sRNA不同,SgrS作为一种双功能sRNA,除具有转录后调控功能外,还能够翻译出蛋白质SgrT。SgrS广泛存在于肠杆菌中,但不同菌属中SgrS的差异极大。本文主要对SgrS在细菌中的功能、分布及其差异进行综述。

When bacteria face higher glucose concentration, the intake of glucose often leads to a large accumulation of glucose-6-phosphate inside bacteria. When the concentration of phosphoglucose reaches a certain threshold, a toxic stress will be formed to inhibit the metabolism and growth of bacteria. Many bacteria remove this inhibition of sugar stress through the post-transcriptional regulation of a small RNA （sRNA）-SgrS（ sugar transport-related sRNA）. With the assistance of molecular chaperone Hfq, SgrS combines with the corresponding target mRNA by complementary pairing of base pairs, negatively regulates the ptsG and manXYZ mRNAs to reduce carbohydrate intake, and positively regulates the yigL mRNA to increase sugar excretion, thus improving the cellular tolerance to sugar stress. Unlike general sRNAs, SgrS is a dual-function sRNA, as it could be translated into the SgrT protein in addition to its post-transcriptional regulatory function. SgrS is widely distributed in Enterobacteriaceae, but it differs greatly in different genera. This article focuses on the function, distribution and difference of SgrS in bacteria.