RNase G (CafA protein) and RNase E are both required for the 5' maturation of 16S ribosomal RNA

Zhongwei Li, Shilpa Pandit, Murray P. Deutscher

Research output: Contribution to journalArticle

220 Scopus citations

Abstract

In Escherichia coli, rRNA operons are transcribed as 30S precursor molecules that must be extensively processed to generate mature 16S, 23S and 5S rRNA. While it is known that RNase III cleaves the primary transcript to separate the individual rRNAs, there is little information about the secondary processing reactions needed to form their mature 3' and 5' termini. We have now found that inactivation of the endoribonuclease RNase E slows down in vivo maturation of 165 RNA from the 175 RNase III cleavage product. Moreover, in the absence of CafA protein, a homolog of RNase E, formation of 16S RNA also slows down, but in this case a 16.3S intermediate accumulates. When both RNase E and CafA are inactivated, 5' maturation of 16S rRNA is completely blocked. In contrast, 3' maturation is essentially unaffected. The 5' unprocessed precursor that accumulates in the double mutant can be assembled into 30S and 70S ribosomes. Precursors also can be processed in vitro by RNase E and CafA. These data indicate that both RNase E and CafA protein are required for a two step, sequential maturation of the 5' end of 16S rRNA, and that CafA protein is a new ribonuclease. We propose that it be renamed RNase G.

Original languageEnglish (US)
Pages (from-to)2878-2885
Number of pages8
JournalEMBO Journal
Volume18
Issue number10
DOIs
StatePublished - May 17 1999

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Keywords

  • CafA protein
  • Ribosomal RNA
  • RNA processing
  • RNase E
  • RNase G

ASJC Scopus subject areas

  • Genetics
  • Cell Biology

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