Gene expression profile of cerebral cortical cells after Rb family inactivation in progenitors and neurons. Mus musculus

Cell cycle deregulation leads to abnormal proliferation and cell death in a context-specific manner. Cell cycle progression driven via Rb pathway forces neurons to undergo S-phase, resulting in cell death associated with the progression of neuronal degeneration. Nevertheless, some Rb- and Rb family (Rb, p107, and p130)-deficient differentiating neurons can proliferate and form tumors. Here, we found that differentiating cerebral cortical excitatory neurons underwent S-phase progression but not cell division after acute Rb family inactivation in differentiating neurons. However, the differentiating neurons underwent cell division and form tumors when Rb family members were inactivated in cortical progenitors. Differentiating neurons generated from Rb -/-; p107 -/-; p130 -/- (Rb-TKO) progenitors, but not acutely inactivated Rb-TKO differentiating neurons, activated DNA double-strand break (DSB) repair pathway without increasing the tri-methylation of histone H4 at lysine 20 (H4K20M3), which is known to protect from DNA damage. The activation of DSB repair pathway was essential for the cell division of Rb-TKO differentiating neurons. These results suggest that newly-born cortical neurons from progenitors epigenetically become protected from DNA damage and cell division in a Rb family-dependent manner. Overall design: 3 samples of pCAG-control, pCAG-RbTKO, pMAP2-control, and pMAP2-RbTKO cells