Two modes of c-myb activation in virus-induced mouse myeloid tumors.

摘要: Two modes of disruption the protooncogene c-myb by viral insertional mutagenesis in mouse myeloid tumor cells are described. The first mode was found six tumors which a Moloney murine leukemia virus component had inserted same transcriptional orientation upstream 5'-most exon with v-myb homology (vE1). cDNA sequence data indicate presence truncated mRNA that is initiated 5' long terminal repeat integrated provirus and processed via cryptic splice donor gag region to acceptor site vE1 gene, thus removing remaining downstream myb intronic sequences. Unlike most gag-onc transcripts, sequences hybrid transcript were not reading frame. It presumed provides translation initiation for novel amino-truncated protein. second insertion at 3' side c-myb, results synthesis small (approximately 2 kilobase) transcript. TGA termination codon elimination 240 normal amino acid residues from carboxyl terminus tumor-specific These suggest proteins play role neoplastic transformation cells.