IRES-induced conformational changes in the ribosome and the mechanism of translation initiation by internal ribosomal entry.

ABSTRACT: Translation of the genomes of several positive-sense RNA viruses follows end-independent initiation on an internal ribosomal entry site (IRES) in the viral mRNA. There are four major IRES groups, and despite major differences in the mechanisms that they use, one unifying characteristic is that each mechanism involves essential non-canonical interactions of the IRES with components of the canonical translational apparatus. Thus the approximately 200nt.-long Type 4 IRESs (epitomized by Cricket paralysis virus) bind directly to the intersubunit space on the ribosomal 40S subunit, followed by joining to a 60S subunit to form active ribosomes by a factor-independent mechanism. The approximately 300nt.-long type 3 IRESs (epitomized by Hepatitis C virus) binds independently to eukaryotic initiati

SUBMITTER: Hellen CU 

PROVIDER: S-EPMC2935204 | biostudies-literature | 2009 Sep-Oct

REPOSITORIES: biostudies-literature