Evidence that a threshold of serine/arginine-rich (SR) proteins recruits CFIm to promote rous sarcoma virus mRNA 3' end formation

Virology. 2016 Nov:498:181-191. doi: 10.1016/j.virol.2016.08.021. Epub 2016 Sep 4.

Abstract

The weak polyadenylation site (PAS) of Rous sarcoma virus (RSV) is activated by the juxtaposition of SR protein binding sites within the spatially separate negative regulator of splicing (NRS) element and the env RNA splicing enhancer (Env enhancer), which are far upstream of the PAS. Juxtaposition occurs by formation of the NRS - 3' ss splicing regulatory complex and is thought to provide a threshold of SR proteins that facilitate long-range stimulation of the PAS. We provide evidence for the threshold model by showing that greater than three synthetic SR protein binding sites are needed to substitute for the Env enhancer, that either the NRS or Env enhancer alone promotes polyadenylation when the distance to the PAS is decreased, and that SR protein binding sites promote binding of the polyadenylation factor cleavage factor I (CFIm) to the weak PAS. These observations may be relevant for cellular PASs.

Keywords: 3′ end processing; CFIm; Polyadenylation; RNA splicing; Rous sarcoma virus; SR proteins.

Publication types

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

MeSH terms

  • Animals
  • Binding Sites
  • Cell Line
  • Gene Order
  • Open Reading Frames
  • Poly A
  • Polyadenylation*
  • Protein Binding
  • RNA, Messenger*
  • RNA, Viral*
  • RNA-Binding Proteins / metabolism*
  • Rous sarcoma virus / genetics*
  • Rous sarcoma virus / metabolism*
  • mRNA Cleavage and Polyadenylation Factors / metabolism*

Substances

  • RNA, Messenger
  • RNA, Viral
  • RNA-Binding Proteins
  • mRNA Cleavage and Polyadenylation Factors
  • Poly A