The Bin3 RNA Methyltransferase Targets 7SK RNA to Control Transcription and Translation

Wiley Interdiscip Rev RNA. Sep-Oct 2012;3(5):633-47. doi: 10.1002/wrna.1123. Epub 2012 Jun 27.

Abstract

Bicoid-interacting protein 3 (Bin3) is a conserved RNA methyltransferase found in eukaryotes ranging from fission yeast to humans. It was originally discovered as a Bicoid (Bcd)-interacting protein in Drosophila, where it is required for anterior-posterior and dorso-ventral axis determination in the early embryo. The mammalian ortholog of Bin3 (BCDIN3), also known as methyl phosphate capping enzyme (MePCE), plays a key role in repressing transcription. In transcription, MePCE binds the non-coding 7SK RNA, which forms a scaffold for an RNA-protein complex that inhibits positive-acting transcription elongation factor b, an RNA polymerase II elongation factor. MePCE uses S-adenosyl methionine to transfer a methyl group onto the γ-phosphate of the 5' guanosine of 7SK RNA generating an unusual cap structure that protects 7SK RNA from degradation. Bin3/MePCE also has a role in translation regulation. Initial studies in Drosophila indicate that Bin3 targets 7SK RNA and stabilizes a distinct RNA-protein complex that assembles on the 3'-untranslated region of caudal mRNAs to prevent translation initiation. Much remains to be learned about Bin3/MeCPE function, including how it recognizes 7SK RNA, what other RNA substrates it might target, and how widespread a role it plays in gene regulation and embryonic development.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Conserved Sequence
  • Drosophila
  • Humans
  • Microfilament Proteins / metabolism*
  • Models, Biological
  • Models, Molecular
  • Protein Binding
  • Protein Biosynthesis*
  • Ribonucleoproteins, Small Nuclear / metabolism*
  • Schizosaccharomyces
  • Transcription, Genetic*

Substances

  • BIN3 protein, human
  • Microfilament Proteins
  • Ribonucleoproteins, Small Nuclear