An “analog sensitive” CDK7 mutant (CDK7as) was devised which operates normally but is inhibited by an ATP analog competitive inhibitor. Inhibition of CDK7as was correlated with a reduction in CTD phosphorylation, where high inhibition led to very little instances of phosphorylated CTD-Ser5 (the phosphorylation target of CDK7 on CTD).
A "sensitive to analog" mutant of CDK7 (CDK7as) was created, which functions properly but is hindered by an ATP analog competitive inhibitor. The suppression of CDK7as was associated with a decrease in CTD phosphorylation, where high levels of inhibition resulted in very few instances of phosphorylated CTD-Ser5.