Identification of MazF Homologue in Legionella pneumophila Which Cleaves RNA at the AACU Sequence

J Mol Microbiol Biotechnol. 2018;28(6):269-280. doi: 10.1159/000497146. Epub 2019 Mar 20.

Abstract

MazF is a sequence-specific endoribonuclease that is widely conserved in bacteria and archaea. Here, we found an MazF homologue (MazF-lp; LPO-p0114) in Legionella pneumophila. The mazF-lp gene overlaps 14 base pairs with the upstream gene mazE-lp (MazE-lp; LPO-p0115). The induction of mazF-lp caused cell growth arrest, while mazE-lp co-induction recovered cell growth in Escherichia coli. In vivo and in vitro primer extension experiments showed that MazF-lp is a sequence-specific endoribonuclease cleaving RNA at AACU. The endoribonuclease activity of purified MazF-lp was inhibited by purified MazE-lp. We found that MazE-lp and the MazEF-lp complex specifically bind to the palindromic sequence present in the 5'-untranslated region of the mazEF-lp operon. MazE-lp and MazEF-lp both likely function as a repressor for the mazEF-lp operon and for other genes, including icmR, whose gene product functions as a secretion chaperone for the IcmQ pore-forming protein, by specifically binding to the palindromic sequence in 5'-UTR of these genes.

Keywords: MazF; Toxin; Toxin-antitoxin system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Endoribonucleases / genetics
  • Endoribonucleases / metabolism*
  • Gene Expression Regulation, Bacterial
  • Legionella pneumophila / enzymology*
  • Legionella pneumophila / genetics
  • Operon
  • RNA / metabolism*

Substances

  • Bacterial Proteins
  • RNA
  • Endoribonucleases