大肠杆菌cafA基因编码一种新型核糖核酸酶，命名为核糖核酸酶G，参与16S核糖体RNA 5'端的加工过程。

Escherichia coli cafA gene encodes a novel RNase, designated as RNase G, involved in processing of the 5' end of 16S rRNA.

作者信息

Wachi M, Umitsuki G, Shimizu M, Takada A, Nagai K

机构信息

Department of Bioengineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8501, Japan.

出版信息

Biochem Biophys Res Commun. 1999 Jun 7;259(2):483-8. doi: 10.1006/bbrc.1999.0806.

DOI:10.1006/bbrc.1999.0806

PMID:10362534

Abstract

We found that the Escherichia coli cafA::cat mutant accumulated a precursor of 16S rRNA. This precursor migrated to the same position with 16.3S precursor found in the BUMMER strain that is known to be deficient in the 5' end processing of 16S rRNA. Accumulation of 16. 3S rRNA in the BUMMER mutant was complemented by introduction of a plasmid carrying the cafA gene. The mutant type cafA gene cloned from the BUMMER strain had a 11-bp deletion in its coding region. A small amount of the mature 16S rRNA was still formed in the cafA::cat mutant. This residual activity was found to be due to RNase E encoded by the rne/ams gene by rifampicin-chase experiments of the cafA::cat ams1 double mutant. These results indicated that the cafA gene encodes a novel RNase responsible for processing of the 5' end of 16S rRNA.

摘要

我们发现大肠杆菌cafA::cat突变体积累了16S rRNA的前体。该前体迁移到与BUMMER菌株中发现的16.3S前体相同的位置，已知该菌株在16S rRNA的5'末端加工方面存在缺陷。通过引入携带cafA基因的质粒，BUMMER突变体中16.3S rRNA的积累得到了互补。从BUMMER菌株克隆的突变型cafA基因在其编码区有一个11bp的缺失。在cafA::cat突变体中仍形成少量成熟的16S rRNA。通过cafA::cat ams1双突变体的利福平追踪实验发现，这种残余活性是由于rne/ams基因编码的RNase E所致。这些结果表明，cafA基因编码一种负责加工16S rRNA 5'末端的新型核糖核酸酶。