Unknown

Dataset Information

0

Structural determinants of an internal ribosome entry site that direct translational reading frame selection.


ABSTRACT: The dicistrovirus intergenic internal ribosome entry site (IGR IRES) directly recruits the ribosome and initiates translation using a non-AUG codon. A subset of IGR IRESs initiates translation in either of two overlapping open reading frames (ORFs), resulting in expression of the 0 frame viral structural polyprotein and an overlapping +1 frame ORFx. A U-G base pair adjacent to the anticodon-like pseudoknot of the IRES directs +1 frame translation. Here, we show that the U-G base pair is not absolutely required for +1 frame translation. Extensive mutagenesis demonstrates that 0 and +1 frame translation can be uncoupled. Ribonucleic acid (RNA) structural probing analyses reveal that the mutant IRESs adopt distinct conformations. Toeprinting analysis suggests that the reading frame is selected at a step downstream of ribosome assembly. We propose a model whereby the IRES adopts conformations to occlude the 0 frame aminoacyl-tRNA thereby allowing delivery of the +1 frame aminoacyl-tRNA to the A site to initiate translation of ORFx. This study provides a new paradigm for programmed recoding mechanisms that increase the coding capacity of a viral genome.

SUBMITTER: Ren Q 

PROVIDER: S-EPMC4132737 | biostudies-literature | 2014 Aug

REPOSITORIES: biostudies-literature

altmetric image

Publications

Structural determinants of an internal ribosome entry site that direct translational reading frame selection.

Ren Qian Q   Au Hilda H T HH   Wang Qing S QS   Lee Seonghoon S   Jan Eric E  

Nucleic acids research 20140718 14


The dicistrovirus intergenic internal ribosome entry site (IGR IRES) directly recruits the ribosome and initiates translation using a non-AUG codon. A subset of IGR IRESs initiates translation in either of two overlapping open reading frames (ORFs), resulting in expression of the 0 frame viral structural polyprotein and an overlapping +1 frame ORFx. A U-G base pair adjacent to the anticodon-like pseudoknot of the IRES directs +1 frame translation. Here, we show that the U-G base pair is not abso  ...[more]

Similar Datasets

| S-EPMC4664324 | biostudies-literature
| S-EPMC3306683 | biostudies-literature
| S-EPMC114096 | biostudies-literature
| S-EPMC3479486 | biostudies-literature
| S-EPMC6052288 | biostudies-literature
| S-EPMC5499600 | biostudies-literature
| S-EPMC3783170 | biostudies-literature
| S-EPMC2770845 | biostudies-literature
| S-EPMC4096041 | biostudies-literature
| S-EPMC4114401 | biostudies-literature