Structural basis for the biological relevance of the invariant apical stem in IRES-mediated translation.

ABSTRACT: RNA structure plays a fundamental role in internal initiation of translation. Picornavirus internal ribosome entry site (IRES) are long, efficient cis-acting elements that recruit the ribosome to internal mRNA sites. However, little is known about long-range constraints determining the IRES RNA structure. Here, we sought to investigate the functional and structural relevance of the invariant apical stem of a picornavirus IRES. Mutation of this apical stem revealed better performance of G:C compared with C:G base pairs, demonstrating that the secondary structure solely is not sufficient for IRES function. In turn, mutations designed to disrupt the stem abolished IRES activity. Lack of tolerance to accept genetic variability in the apical stem was supported by the presence of coupled covaria

SUBMITTER: Fernandez N 

PROVIDER: S-EPMC3201876 | biostudies-literature | 2011 Oct

REPOSITORIES: biostudies-literature