Ribosomal 18S rRNA base pairs with mRNA during eukaryotic translation initiation.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27554013.
- Also identified by DOI 10.1038/ncomms12622 and PMC identifier 4999511.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Eukaryotic mRNAs often contain a Kozak sequence that helps tether the ribosome to the AUG start codon. The mRNA of histone H4 (h4) does not undergo classical ribosome scanning but has evolved a specific tethering mechanism. The cryo-EM structure of the rabbit ribosome complex with mouse h4 shows that the mRNA forms a folded, repressive structure at the mRNA entry site on the 40S subunit next to the tip of helix 16 of 18S ribosomal RNA (rRNA). Toe-printing and mutational assays reveal that an interaction exists between a purine-rich sequence in h4 mRNA and a complementary UUUC sequence of helix h16. Together the present data establish that the h4 mRNA harbours a sequence complementary to an 18S rRNA sequence which tethers the mRNA to the ribosome to promote proper start codon positioning, complementing the interactions of the 40S subunit with the Kozak sequence that flanks the AUG start codon.
Medical subject headings
- Peptide Chain Initiation, Translational
- RNA, Messenger
- RNA, Ribosomal, 18S