Dark-induced mRNA instability involves RNase E/G-type endoribonuclease cleavage at the AU-box and SD sequences in cyanobacteria

Mol Genet Genomics. 2007 Sep;278(3):331-46. doi: 10.1007/s00438-007-0254-9. Epub 2007 Jul 28.


Light-responsive gene expression is crucial to photosynthesizing organisms. Here, we studied functions of cis-elements (AU-box and SD sequences) and a trans-acting factor (ribonuclease, RNase) in light-responsive expression in cyanobacteria. The results indicated that AU-rich nucleotides with an AU-box, UAAAUAAA, just upstream from an SD confer instability on the mRNA under darkness. An RNase E/G homologue, Slr1129, of the cyanobacterium Synechocystis sp. strain PCC 6803 was purified and confirmed capable of endoribonucleolytic cleavage at the AU- (or AG)-rich sequences in vitro. The cleavage depends on the primary target sequence and secondary structure of the mRNA. Complementation tests using Escherichia coli rne/rng mutants showed that Slr1129 fulfilled the functions of both the RNase E and RNase G. An analysis of systematic mutations in the AU-box and SD sequences showed that the cis-elements also affect significantly mRNA stability in light-responsive genes. These results strongly suggested that dark-induced mRNA instability involves RNase E/G-type cleavage at the AU-box and SD sequences in cyanobacteria. The mechanical impact and a possible common mechanism with RNases for light-responsive gene expression are discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Binding Sites / genetics
  • Darkness
  • Endoribonucleases / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Genes, Bacterial
  • Genetic Complementation Test
  • Models, Genetic
  • Mutagenesis, Site-Directed
  • Nucleic Acid Conformation
  • Photosystem II Protein Complex / genetics
  • Photosystem II Protein Complex / metabolism
  • RNA Stability
  • RNA, Bacterial / chemistry
  • RNA, Bacterial / genetics*
  • RNA, Bacterial / metabolism*
  • RNA, Messenger / chemistry
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Synechocystis / genetics*
  • Synechocystis / metabolism*


  • Bacterial Proteins
  • Photosystem II Protein Complex
  • RNA, Bacterial
  • RNA, Messenger
  • Recombinant Proteins
  • photosystem II, psbA subunit
  • Endoribonucleases
  • ribonuclease E