Recent findings implicate alternate core promoter recognition complexes in regulating
cellular differentiation. Here we report a spatial segregation of the alternative core factor
TAF3, but not canonical TFIID subunits, away from the nuclear periphery, where the key
myogenic gene MyoD is preferentially localized in myoblasts. This segregation is correlated
with the differential occupancy of TAF3 versus TFIID at the MyoD promoter. Loss of this
segregation by modulating either the intranuclear location of the MyoD gene or TAF3 protein …

To begin this study, we determined the positions of MyoD by immuno-DNA FISH in mouse
C2C12 myoblasts. Visualization of the nuclear periphery by an antibody against nuclear
Lamin B shows that the MyoD gene is preferentially localized to the nuclear periphery (Fig.
1A, B;