title: Enhanced c-Ki-ras expression associated with Friend virus integration in a bone marrow-derived mouse cell line.
abstract: We have investigated the molecular basis for a 25- to 30-fold overexpression of the c-Ki-ras oncogene in a mouse bone marrow-derived, early myeloid cell line, 416B. Southern blot hybridizations revealed that the 416B cells contain a rearranged c-Ki-ras gene in addition to an apparently normal gene. Molecular cloning and DNA sequence analyses demonstrated that the rearrangement involves the insertion of a 3.5-kilobase-pair segment of Friend virus that includes the envelope gene (env) and 3' long terminal repeat. The Friend provirus is positioned between a 5' nontranslated exon (exon phi) and the first coding exon (exon 1) of the c-Ki-ras gene in the same transcriptional orientation. Results of RNA blot analyses indicate that transcription from the rearranged gene initiates at a promoter that excludes sequences in exon phi. The data support the hypothesis that enhanced c-Ki-ras expression in the 416B cells results from integration of a Friend provirus within this gene.
mesh_terms: D000818:Animals; D001483:Base Sequence; D001854:Bone Marrow Cells; D002460:Cell Line; D002472:Cell Transformation, Viral; D003001:Cloning, Molecular; D005260:Female; D005622:Friend murine leukemia virus / Q000502:physiology*; D005786:Gene Expression Regulation; D051379:Mice; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis*; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis; D012091:Repetitive Sequences, Nucleic Acid; D014158:Transcription, Genetic; D014759:Viral Envelope Proteins / Q000235:genetics
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014759:Viral Envelope Proteins