CDK7 and cancer: Together, these data demonstrate that: (1) Cdk7 is essential for the phosphorylation thus activation of RNAPII in neurons; (2) consistent with the results obtained in cancer cells and stem cells (Chipumuro et al., 2014; Christensen et al., 2014; Kwiatkowski et al., 2014; Nilson et al., 2015), in post-mitotic neurons, THZ1 effectively and irreversibly inhibits RNAPII CTD phosphorylation with similar potency via covalent binding to Cdk7.