Format

Send to

Choose Destination
See comment in PubMed Commons below
Nucleic Acids Res. 2014 May;42(9):5742-54. doi: 10.1093/nar/gku177. Epub 2014 Mar 5.

Identification of novel non-canonical RNA-binding sites in Gemin5 involved in internal initiation of translation.

Author information

1
Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049-Madrid, Spain.
2
Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028-Barcelona, Spain.
3
Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, 08028-Barcelona, Spain Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluis Companys 23, 08010-Barcelona, Spain.
4
Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049-Madrid, Spain emartinez@cbm.csic.es.

Abstract

Ribonucleic acid (RNA)-binding proteins are key players of gene expression control. We have shown that Gemin5 interacts with internal ribosome entry site (IRES) elements and modulates initiation of translation. However, little is known about the RNA-binding sites of this protein. Here we show that the C-terminal region of Gemin5 bears two non-canonical bipartite RNA-binding sites, encompassing amino acids 1297-1412 (RBS1) and 1383-1508 (RBS2). While RBS1 exhibits greater affinity for RNA than RBS2, it does not affect IRES-dependent translation in G5-depleted cells. In solution, the RBS1 three-dimensional structure behaves as an ensemble of flexible conformations rather than having a defined tertiary structure. However, expression of the polypeptide G51383-1508, bearing the low RNA-binding affinity RBS2, repressed IRES-dependent translation. A comparison of the RNA-binding capacity and translation control properties of constructs expressed in mammalian cells to that of the Gemin5 proteolysis products observed in infected cells reveals that non-repressive products accumulated during infection while the repressor polypeptide is not stable. Taken together, our results define the low affinity RNA-binding site as the minimal element of the protein being able to repress internal initiation of translation.

PMID:
24598255
PMCID:
PMC4027194
DOI:
10.1093/nar/gku177
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Silverchair Information Systems Icon for PubMed Central
    Loading ...
    Support Center