Entrapping ribosomes for viral translation: tRNA mimicry as a molecular Trojan horse.
Turnip yellow mosaic virus (TYMV) has a genomic plus-strand RNA with a 5' cap followed by overlapping and different reading frames for the movement protein and polyprotein, while the distal coat protein cistron is translated from a subgenomic RNA. The 3'-untranslated region harbors a tRNA-like structure (TLS) to which a valine moiety can be added and it is indispensable for virus viability. Here, we report about a surprising interaction between TYMV-RNA-programmed ribosomes and 3'-valylated TLS that yields polyprotein with the valine N terminally incorporated by a translation mechanism resistant to regular initiation inhibitors. Disruption of the TLS exclusively abolishes polyprotein synthesis, which can be restored by adding excess TLS in trans. Our observations imply a novel eukaryotic mechanism for internal initiation of mRNA translation.
Barends
Sharief
S
Department of Biochemistry, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
Bink
Hugo H J
HH
van den Worm
Sjoerd H E
SH
Pleij
Cornelis W A
CW
Kraal
Barend
B
D020413:3' Untranslated Regions / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008957:Models, Genetic; D018716:Molecular Mimicry; D009029:Mosaic Viruses / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000378:metabolism; D012343:RNA, Transfer / Q000235:genetics*; D012367:RNA, Viral; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism*; D013379:Substrate Specificity; D014908:Triticum; D017806:Tymovirus / Q000235:genetics; D014633:Valine / Q000737:chemistry / Q000378:metabolism; D014764:Viral Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
D020413:3' Untranslated Regions; D012333:RNA, Messenger; D012367:RNA, Viral; D014764:Viral Proteins; D012343:RNA, Transfer; D014633:Valine