Oligomerization activity of a double-stranded RNA-binding domain

FEBS Lett. 2004 Sep 10;574(1-3):25-30. doi: 10.1016/j.febslet.2004.07.080.


Xenopus laevis RNA-binding protein A (Xlrbpa) is a highly conserved, ubiquitously expressed hnRNP- and ribosome-associated RNA-binding protein that contains three double stranded RNA-binding domains (dsRBDs) in tandem arrangement. A two-hybrid screen with Xlrbpa as a bait recovered Xlrbpa itself as the strongest interaction partner, indicating multimerization of this protein. To search for regions responsible for the observed interaction, we conducted two-hybrid assays with Xlrbpa deletion constructs and identified the third dsRBD of Xlrbpa as the exclusive interacting domain. Additionally, these results were confirmed by coimmunoprecipitation experiments with truncated proteins expressed both in yeast and Xenopus oocytes. In PACT, the human homologue of Xlrbpa, we could demonstrate that the third dsRBD displays the same multimerization activity. Interestingly, this domain is essential for the activation of the dsRNA-activated protein kinase PKR. Addition of RNAses to coimmunoprecipitation experiments did not affect the dimerization, suggesting that the interaction is independent of RNA-binding. We report here a homomultimerization activity of a type B dsRBD and suggest possible implications that include a model for PKR activation by PACT.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Biopolymers
  • Cloning, Molecular
  • DNA Primers
  • Molecular Sequence Data
  • RNA, Double-Stranded / metabolism*
  • Sequence Homology, Amino Acid
  • Two-Hybrid System Techniques
  • Xenopus Proteins / chemistry
  • Xenopus Proteins / metabolism*
  • Xenopus laevis


  • Biopolymers
  • DNA Primers
  • RNA, Double-Stranded
  • Xenopus Proteins