Granger L L, O'Hara E B, Wang R F, Meffen F V, Armstrong K, Yancey S D, Babitzke P, Kushner S R
Department of Genetics, University of Georgia, Athens 30602-7223, USA.
J Bacteriol. 1998 Apr;180(7):1920-8. doi: 10.1128/JB.180.7.1920-1928.1998.
We have identified a gene in Escherichia coli that is required for both the normal decay of mRNA and RNA synthesis. Originally designated mrsC (mRNA stability), the mrsC505 mutation described here is, in fact, an allele of the hflB/ftsH locus (R.-F. Wang et al., J. Bacteriol. 180:1929-1938, 1998). Strains carrying the thermosensitive mrsC505 allele stopped growing soon after the temperature was shifted to 44 degrees C but remained viable for several hours. Net RNA synthesis stopped within 20 min after the shift, while DNA and protein synthesis continued for over 60 min. At 44 degrees C, the half-life of total pulse-labeled RNA rose from 2.9 min in a wild-type strain to 5.9 min in the mrsC505 single mutant. In an rne-1 mrsC505 double mutant, the average half-life was 19.8 min. Inactivating mrsC significantly increased the half-lives of the trxA, cat, secG, and kan mRNAs, particularly in an mrsC505 pnp-7 rnb-500 rne-1 multiple mutant. In addition, Northern analysis showed dramatic stabilizations of full-length mRNAs in a variety of mrsC505 multiple mutants at 44 degrees C. These results suggest that MrsC, directly or indirectly, controls endonucleolytic processing of mRNAs that may be independent of the RNase E-PNPase-RhlB multiprotein complex.
我们在大肠杆菌中鉴定出一个基因，它对于mRNA的正常降解和RNA合成都是必需的。最初命名为mrsC（mRNA稳定性），这里描述的mrsC505突变实际上是hflB/ftsH位点的一个等位基因（R.-F. Wang等人，《细菌学杂志》180:1929 - 1938，1998）。携带温度敏感型mrsC505等位基因的菌株在温度转移到44摄氏度后不久就停止生长，但在数小时内仍保持存活。转移后20分钟内净RNA合成停止，而DNA和蛋白质合成持续超过60分钟。在44摄氏度时，总脉冲标记RNA的半衰期从野生型菌株中的2.9分钟增加到mrsC505单突变体中的5.9分钟。在rne - 1 mrsC505双突变体中，平均半衰期为19.8分钟。使mrsC失活显著增加了trxA、cat、secG和kan mRNA的半衰期，特别是在mrsC505 pnp - 7 rnb - 500 rne - 1多突变体中。此外，Northern分析显示在44摄氏度时，多种mrsC505多突变体中全长mRNA有显著的稳定化。这些结果表明，MrsC直接或间接控制mRNA的内切核酸酶加工，这可能独立于RNase E - PNPase - RhlB多蛋白复合物。
