Myc targets

There is intense effort to identify transcriptional targets of the c-Myc proto-oncogene that can account for its role in cell growth and division. In the January 16 Nature, Natividad Gomez-Roman and colleagues report that c-Myc directly activates transcription by RNA polymerase III (pol III) (Nature, 421:290-294, January 16, 2003).

Analysis of human fibroblasts and cells from c-Myc knockout mice, showed that c-Myc is important for the transcription of pol III-regulated genes, such as the B2 repetitive gene family, 5S rRNA and tRNA genes. Chromatin immunoprecipitation experiments showed that c-Myc is associated with pol III target genes in vivo. Gomez-Roman et al. reported a direct interaction between the regulatory domain of c-Myc and TFIIIB, a pol III-specific general transcription factor.

These new Myc targets further our understanding of how c-Myc regulates growth by activating pol II and pol III transcriptional programs.