Chromosome translocation activates heterogeneously initiated, bipolar transcription of a mouse c-myc gene.
In many mouse plasmacytomas, the active c-myc gene has been truncated by chromosome translocation with the resultant severance of the protein-coding sequence from the normal promoter. Transcripts of such truncated c-myc genes were analyzed by Northern blotting, nuclease S1 mapping, primer extension assays and cDNA cloning. We conclude that transcription originates from multiple initiation sites on both c-myc coding and non-coding strands with the two-sets of transcripts derived from adjacent but essentially non-overlapping regions located greater than 1 kb from the translocation junction. In X63Ag8, where c-myc is translocated to the immunoglobulin C gamma 2b gene, the c-myc non-coding strand transcripts include the translocation junction and then splice directly into the gamma 2b CH1 exon. We propose that chromosome translocation activates a cryptic promoter in the first intron and that the heterogeneously initiated, bipolar transcription reflects the absence of a suitably placed TATA box element.
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005786:Gene Expression Regulation; D007142:Immunoglobulin gamma-Chains / Q000235:genetics; D051379:Mice; D009857:Oncogenes; D010954:Plasmacytoma / Q000235:genetics*; D014158:Transcription, Genetic; D014178:Translocation, Genetic
D007142:Immunoglobulin gamma-Chains; D004247:DNA