Termination and read-through proteins encoded by genome segment 9 of Colorado tick fever virus.
Genome segment 9 (Seg-9) of Colorado tick fever virus (CTFV) is 1884 bp long and contains a large open reading frame (ORF; 1845 nt in length overall), although a single in-frame stop codon (at nt 1052-1054) reduces the ORF coding capacity by approximately 40 %. However, analyses of highly conserved RNA sequences in the vicinity of the stop codon indicate that it belongs to a class of 'leaky terminators'. The third nucleotide positions in codons situated both before and after the stop codon, shows the highest variability, suggesting that both regions are translated during virus replication. This also suggests that the stop signal is functionally leaky, allowing read-through translation to occur. Indeed, both the truncated 'termination' protein and the full-length 'read-through' protein (VP9 and VP9', respectively) were detected in CTFV-infected cells, in cells transfected with a plasmid expressing only Seg-9 protein products, and in the in vitro translation products from undenatured Seg-9 ssRNA. The ratios of full-length and truncated proteins generated suggest that read-through may be down-regulated by other viral proteins. Western blot analysis of infected cells and purified CTFV showed that VP9 is a structural component of the virion, while VP9' is a non-structural protein.
Unité des Virus Emergents (EA 3292, IFR 48): EFS Alpes-Méditerranée and Université de la Méditerranée, Faculté de Médecine de Marseille, Marseille 13005, France.
Fauziah Mohd
FM
Jaafar
Unité des Virus Emergents (EA 3292, IFR 48): EFS Alpes-Méditerranée and Université de la Méditerranée, Faculté de Médecine de Marseille, Marseille 13005, France.
Houssam
H
Attoui
Unité des Virus Emergents (EA 3292, IFR 48): EFS Alpes-Méditerranée and Université de la Méditerranée, Faculté de Médecine de Marseille, Marseille 13005, France.
Philippe
P
de Micco
Maladies virales émergents et systèmes d'information UR 034, Institut de Recherche pour le Développement, Faculté de Médecine de Marseille, Marseille 13005, France.|Unité des Virus Emergents (EA 3292, IFR 48): EFS Alpes-Méditerranée and Université de la Méditerranée, Faculté de Médecine de Marseille, Marseille 13005, France.
Xavier
X
de Lamballerie
D000818:Animals; D015153:Blotting, Western; D002522:Chlorocebus aethiops; D018388:Codon, Terminator; D003122:Colorado tick fever virus / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D016679:Genome, Viral; D016366:Open Reading Frames; D014176:Protein Biosynthesis; D014709:Vero Cells
D018388:Codon, Terminator