Fig. 4

Selective inhibition of CDK7 or CDK9 diminishes pS187-H1.4 levels globally and at specific genes. a HeLa cells were treated with DMSO (solvent control) or increasing amounts of THZ1 to selectively inhibit CDK7 for 1, 2 or 4 h. The global abundance of pS187-H1.4 and H1.4 was assessed by immunoblotting whole-cell lysates. b HeLa cells were treated with DMSO (solvent control), 1 μM THZ1 or 1 μM FLVP for 1 h to selectively inhibit CDK7 and CDK9, respectively. Immunoblotting of whole-cell lysates with the indicated antisera was used to monitor the abundance of phosphorylated forms of RNAP II and selected H1 variants. The numbers below each panel indicate densitometry for the treated samples relative to the control sample. c HeLa cells were treated as in (b) and the levels of pS187-H1.4 at the promoters or gene bodies of housekeeping genes were assessed by ChIP-qPCR. Negative control ChIP assays employed non-immune rabbit immunoglobulin (rIg) in place of primary antisera. The data are expressed as percent relative to input DNA (mean ± s.e.m., *p < 0.05; **p < 0.01; ***p < 0.001)