Cap-dependent translation without base-by-base scanning of an messenger ribonucleic acid.
'Ribosome scanning' is the generally accepted mechanism for explaining how a ribosome finds an initiation codon located far removed from the ribosome recruiting site (cap structure). However, the molecular characteristics of ribosome scanning along 5' untranslated regions (UTRs) remain obscure. Herein, using a rabbit reticulocyte lysate (RRL) system and artificial ribonucleic acid (RNA) constructs composed of a capped leader RNA and an uncapped reporter RNA annealed through a double-stranded RNA (dsRNA) bridge, we show that the ribosome can efficiently bypass a stable, dsRNA region without melting the structure. The insertion of an upstream open reading frame in the capped leader RNA impaired the translation of reporter RNA, indicating that a ribosome associated with the 5'-end explores the regions upstream of the dsRNA bridge in search of the initiation codon. These data indicate that a ribosome may skip part(s) of an messenger RNA 5'UTR without thoroughly scanning it.
PBC, Department of Life Science, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk 790-784, Republic of Korea.
Ki Young
KY
Paek
Sung Mi
SM
Park
Ka Young
KY
Hong
Sung Key
SK
Jang
D020121:5' Untranslated Regions; D016366:Open Reading Frames; D014176:Protein Biosynthesis; D012315:RNA Caps / Q000378:metabolism*; D012330:RNA, Double-Stranded / Q000378:metabolism; D012333:RNA, Messenger / Q000737:chemistry
D020121:5' Untranslated Regions; D012315:RNA Caps; D012330:RNA, Double-Stranded; D012333:RNA, Messenger