Archaeal fibrillarin-Nop5 heterodimer 2'- O-methylates RNA independently of the C/D guide RNP particle

RNA. 2017 Sep;23(9):1329-1337. doi: 10.1261/rna.059832.116. Epub 2017 Jun 2.

Abstract

Archaeal fibrillarin (aFib) is a well-characterized S-adenosyl methionine (SAM)-dependent RNA 2'-O-methyltransferase that is known to act in a large C/D ribonucleoprotein (RNP) complex together with Nop5 and L7Ae proteins and a box C/D guide RNA. In the reaction, the guide RNA serves to direct the methylation reaction to a specific site in tRNA or rRNA by sequence complementarity. Here we show that a Pyrococcus abyssi aFib-Nop5 heterodimer can alone perform SAM-dependent 2'-O-methylation of 16S and 23S ribosomal RNAs in vitro independently of L7Ae and C/D guide RNAs. Using tritium-labeling, mass spectrometry, and reverse transcription analysis, we identified three in vitro 2'-O-methylated positions in the 16S rRNA of P. abyssi, positions lying outside of previously reported pyrococcal C/D RNP methylation sites. This newly discovered stand-alone activity of aFib-Nop5 may provide an example of an ancestral activity retained in enzymes that were recruited to larger complexes during evolution.

Keywords: Archaea; C/D RNP; Nop5; RNA 2′-O-methylation; fibrillarin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaea / genetics*
  • Archaea / metabolism*
  • Chromosomal Proteins, Non-Histone / chemistry
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Methylation
  • Nucleic Acid Conformation
  • Protein Binding
  • Protein Multimerization
  • RNA, Archaeal / genetics*
  • RNA, Archaeal / metabolism*
  • RNA, Ribosomal, 16S / chemistry
  • RNA, Ribosomal, 16S / genetics
  • RNA, Ribosomal, 16S / metabolism
  • RNA, Ribosomal, 23S / chemistry
  • RNA, Ribosomal, 23S / genetics
  • RNA, Ribosomal, 23S / metabolism
  • Ribonucleoproteins / chemistry
  • Ribonucleoproteins / metabolism*
  • Ribonucleoproteins, Small Nucleolar / chemistry
  • Ribonucleoproteins, Small Nucleolar / metabolism*
  • Substrate Specificity

Substances

  • Chromosomal Proteins, Non-Histone
  • RNA, Archaeal
  • RNA, Ribosomal, 16S
  • RNA, Ribosomal, 23S
  • Ribonucleoproteins
  • Ribonucleoproteins, Small Nucleolar
  • fibrillarin