Figure 3.

CDK7 and cyclin H co-migrate as a 350 kDa complex. Hi-Trap heparin fractions 22 to 24 were analyzed on Sephacryl S-300 gel filtration column. A, Tat-associated CTD kinase activity co-purify with CDK7 and cyclin H. Fractions from the Sephacryl S-300 column fractionation were analyzed for Tat-associated CTD kinase activity and also by Western blotting with antibodies against CDK7 and Cyclin H. B, Fractions from Sephacryl S-300 column fractionation were resolved by 12% SDS PAGE and stained with silver.