Acquisition of an Intracisternal A-Particle Element by a Translocated c-myc Gene in a Murine Plasma Cell Tumor

Abstract

The J558 plasma cell tumor contains two forms of a translocated c-myc gene which are distinguished by virtue of their 3′ flanking sequences. The J558 α4 and α25 myc genes are broken by a 12;15 translocation which links c-myc exon 1 to Cα switch sequences. Comparative restriction mapping and DNA sequence analyses demonstrated that an intracisternal A-particle (IAP) element inserted ~2 kilobases 3′ of an α4-type myc gene to generate the α25 gene copy. The steady-state level of truncated myc RNAs in J558 was comparable to that in another plasma cell tumor line (MPC-11) which harbors a translocated c-myc locus without an IAP element. The significance of these observations for the putative role of IAP elements in the genesis or progression or both of plasma cell tumors is discussed.