Skip to main content
eScholarship
Open Access Publications from the University of California

The role of U2AF35and U2AF65in enhancer-dependent splicing

  • Author(s): Graveley, BR
  • Hertel, KJ
  • Maniatis, TOM
  • et al.
Abstract

Splicing enhancers are RNA sequence elements that promote the splicing of nearby introns. The mechanism by which these elements act is still unclear. Some experiments support a model in which serine-arginine (SR)-rich proteins function as splicing activators by binding to enhancers and recruiting the splicing factor U2AF to an adjacent weak 3′ splice site. In this model, recruitment requires interactions between the SR proteins and the 35-kDa subunit of U2AF (U2AF35). However, more recent experiments have not supported the U2AF recruitment model. Here we provide additional evidence for the recruitment model. First, we confirm that base substitutions that convert weak 3′ splice sites to a consensus sequence, and therefore increase U2AF binding, relieve the requirement for a splicing activator. Second, we confirm that splicing activators are required for the formation of early spliceosomal complexes on substrates containing weak 3′ splice sites. Most importantly, we find that splicing activators promote the binding of both U2AF65and U2AF35to weak 3′ splice sites under splicing conditions. Finally, we show that U2AF35is required for maximum levels of activator-dependent splicing. We conclude that a critical function of splicing activators is to recruit U2AF to the weak 3′ splice sites of enhancer-dependent introns, and that efficient enhancer-dependent splicing requires U2AF35.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View