NF-M TRANS-ACTIVATES THE HUMAN DNA TOPOISOMERASE II-ALPHA PROMOTER INDEPENDENTLY OF C-MYB IN HL-60 CELLS

Identifying transcriptional regulators of DNA topoisomerase II alpha ( topo II alpha) is essential to decipher the mechanisms underlying leuk emia cell resistance to topo II-directed antitumor drugs. We have prev iously reported that the proto-oncogene transcription factor c-Myb tra nsactivates the topo II alpha promoter in several hematopoietic cell l ines. Currently, we investigate whether NF-M, a C/EBP beta family memb er, cooperates with c-Myb in activating topo II alpha transcription. A lthough NF-M is the most efficacious trans-activator of topo II alpha that we have examined (similar to 38-fold over basal), NF-M does not a ppear to be involved in the endogenous transcriptional regulation of t opo II alpha. Interestingly, we report that the sodium butyrate-depend ent induction of the topo II alpha promoter observed previously appear s to be mediated by c-Myb, independent of NF-M. (C) 1997 Elsevier Scie nce Ltd.