Sequence comparison of JSRV with endogenous proviruses: envelope genotypes and a novel ORF with similarity to a G-protein-coupled receptor.
Ovine pulmonary carcinoma, a contagious lung cancer of sheep, is caused by the oncogenic jaagsiekte sheep retrovirus (JSRV) that is closely related to a family of endogenous sheep retroviral sequences (ESRVs). By using exogenous virus-specific U3 oligonucleotide primers, the entire JSRV proviral genome or its 3' part was amplified from tumor DNA. Analysis of these proviral sequences revealed a novel open reading frame (ORF) within the pol coding region, designated ORF X, which was well conserved in ESRV and JSRV sequences. Deduced amino acids of ORF X showed similarity to a portion of the mammalian adenosine receptor subtype 3, a member of the G-protein-coupled receptor family. Comparison of deduced env amino acids of six JSRV strains from three continents identified 15 residues that defined two distinct genotypes of JSRVs. Sequence analysis identified two highly variable regions between JSRV and ESRV in the transmembrane domain of env (TM) and the 3' unique sequence (U3) of the long terminal repeat, from which JSRV-specific DNA probes were derived. By using these DNA probes in Southern hybridization, for the first time we successfully identified JSRV proviral sequences in tumor genomic DNA in the presence of multiple ESRV loci, validating the use of exogenous virus-specific DNA probes in the analysis of oncogenic proviral integration sites and identification of integrated exogenous proviral sequences.
Bai
J
J
Department of Pathology, Colorado State University, Fort Collins, Colorado, 80523, USA.
Bishop
J V
JV
Carlson
J O
JO
DeMartini
J C
JC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015342:DNA Probes; D004279:DNA, Viral; D004285:Dogs; D020077:Endogenous Retroviruses / Q000235:genetics*; D019204:GTP-Binding Proteins; D005784:Gene Amplification; D015751:Genes, pol; D016679:Genome, Viral; D005838:Genotype; D006564:Herpesviridae / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000821:virology; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D011533:Proviruses / Q000235:genetics*; D011648:Pulmonary Adenomatosis, Ovine / Q000821:virology*; D051381:Rats; D011956:Receptors, Cell Surface; D018047:Receptors, Purinergic P1 / Q000235:genetics; D012756:Sheep; D014407:Tumor Cells, Cultured; D016662:Virus Integration
D015342:DNA Probes; D004279:DNA, Viral; D011956:Receptors, Cell Surface; D018047:Receptors, Purinergic P1; D019204:GTP-Binding Proteins