title: Patterns of proviral insertion and deletion in avian leukosis virus-induced lymphomas.
abstract: Sixty-eight lymphomas induced by eight different avian leukosis viruses have been analyzed on Southern blots for virus-induced mutations in the chicken c-myc gene. Sixty-six of the lymphomas exhibited a proviral insertion in c-myc, whereas one exhibited a new transduction of c-myc. Sixty-four of the proviral insertions were in the same transcriptional orientation as c-myc. Two were in the opposite transcriptional orientation. All of the insertions were upstream of the protein-coding sequences of c-myc, with most residing in the first exon or the first intron of c-myc. All of the lymphoma-inducing proviruses had deletions that included either sequences near the 5' long terminal repeat (LTR) or an LTR. The most frequent lymphoma-inducing provirus appeared to have retained both of its LTRs, but had lost sequences near its 5' LTR. The second and third most frequent lymphoma-inducing proviruses consisted of solo LTRs or of proviruses that had lost the 5' LTR as well as some internal sequences. Twenty-four insertions were mapped in c-myc. Each of these mapped to within 150 base pairs of one of the five DNase I-hypersensitive sites that occur in a 3-kilobase region immediately 5' to the protein-coding sequences of c-myc. One lymphoma contained a new c-myc transducing virus. This virus, MYC-3475, caused rapid-onset myelocytomatosis.
mesh_terms: D001354:Avian Leukosis Virus / Q000235:genetics* / Q000302:isolation & purification; D001483:Base Sequence; D002872:Chromosome Deletion; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D004273:DNA, Neoplasm / Q000032:analysis*; D004279:DNA, Viral / Q000032:analysis*; D008223:Lymphoma / Q000235:genetics* / Q000382:microbiology; D009857:Oncogenes; D011519:Proto-Oncogenes; D012091:Repetitive Sequences, Nucleic Acid; D001356:Reticuloendotheliosis virus / Q000235:genetics; D014158:Transcription, Genetic; D014161:Transduction, Genetic
chemical_list: D004251:DNA Transposable Elements; D004273:DNA, Neoplasm; D004279:DNA, Viral