Is the transcriptional regulator BACH1 an activator or a repressor?
BACH1, a basic leucine zipper mammalian transcriptional repressor, negatively regulates heme oxygenase 1 (HMOX1), a key cytoprotective enzyme that has antioxidant and anti-inflammatory activities. In the absence of elevated intracellular heme or oxidative stress, BACH1 functions as a repressor of the enhancers of heme oxygenase-1 (HO-1) gene (Hmox-1) by forming heterodimers with the small Maf proteins such as MafK. Bach1 is recruited to a subset of p53 target genes and contributes to impeding p53 action by promoting histone deacetylation.