Molecular cloning and chromosomal mapping of mouse intronless myc gene acting as a potent apoptosis inducer

Our previous findings suggest that the activation of the rat intronless myc gene provides a selective advantage in tumor suppression through apoptosis induction. In the present study, to examine whether intronless myc gene ac ting as an apoptosis inducer is evolutionarily conserved in mammalian cells , we isolated the mouse intronless myc gene and characterized it. A sequenc e analysis demonstrated that mouse intronless myc gene, ms-myc, has a linea rly opened translatable frame consisting of 1293 bp with 90% homology with that of rat s-myc. The chromosomal locus of ms-myc was identified on chromo some 19B by a fluorescent in situ hybridization (FISH) analysis. Gene trans fection experiments showed that the transient overexpression of ms-Myc with transactivation activity effectively induces cell death in a wild-type p53 -independent manner. In addition, cells stably expressing transfected ms-my c became more susceptible to apoptosis induced by genotoxic stress such as UV-irradiation and hydrogen peroxide compared with untransfected control ce lls. These observations suggest that the rodents commonly contain an s-myc- type of intronless myc gene with apoptosis-inducing activity. (C) 1999 Else vier Science B.V. All rights reserved.