OXIDATIVE STRESS INDUCES THE LEVELS OF A MAFG HOMOLOG IN HAMSTER HA-1CELLS

The Maf family encodes nuclear proteins that recognize AP-1-like respo nse elements. MafB, MafK, MafF, and MafG, are all able to heterodimeri ze with each other, c-fos, and erythroid cell-specific transcription f actor NF-E2, to affect the transcription of target genes. Using the te chnique of differential display, we recently identified a new oxidant- inducible mRNA, designated adapt66, in HA-1 hamster fibroblasts. Cloni ng, partial sequencing, and GenBank analysis of adapt66 revealed stron g homology to chicken mafG, a newly identified member of the maf oncog ene family. The mafG homolog/adapt66 mRNA induction appeared to be dep endent upon calcium; occurred as early as 90 minutes following exposur e of HA-I cells to hydrogen peroxide; and peaked between 5 and 10 hour s after peroxide treatment. It has previously been demonstrated that s everal cellular transcription factors, including Fos, can be induced b y oxidative stress. The induction of the DNA binding sequence mafG hom olog/adapt66 by hydrogen peroxide, and it's known interaction with c-f os, may represent important mechanisms by which oxidative stress can m odulate gene expression.