the number of cycling cortical and cerebellar progenitors at E14.5, ectopic BAF45b expression has no discernable effect (Lessard et al., 2007). Conversely, knockdown of BAF45a, but not BAF45b, leads to a reduced number of proliferative neural progenitors in the same neurogenic regions of the brain. This functional discrepancy stems from the N-terminal domain and the Krüpple zinc finger domain which are highly divergent between the two homologs: deleting either domain from BAF45a prevents its enhancement of progenitor proliferation, but deleting the C-terminal double PHD domain, which is more conserved between BAF45a and BAF45b, does not have a significant effect.
