Modes of c-myc oncogene activation in murine plasmacytomas.

Abstract

The murine c-myc proto-oncogene is activated and inappropriately expressed in murine plasmacytomas (PCs’) by virtue of a reciprocal 12;15 chromosomal translocation (Harris et al.,1982a; Shen-Ong et al.,1982; Crews et al.,1982; Marcu et al.,1983; Adams et al.,1983). In most PCs’, the c-myc gene is broken by the rcpt(12;15) thereby generating a complex family of aberrant myc transcripts which initiate from normally silent promoters within the first myc intron (Marcu et al.,1983; Adams et al.,1983; Stanton et al.,1983). The disruption of the c-myc locus in the PCs’ generally results in elevated levels of such truncated transcripts (Marcu et al.,1983; Mushinski et al.,1983). However, it would seem that the more general consequence of the myc associated rcpt(12;15) is the inappropriate, constitutive expression of c-myc since the normal myc allele is transcriptionally silent in these tumors (Adams et al., 1983; Stanton et al.,1983; Bernard et al.,1983).