Transient ectopic expression of ICP22 causes specific loss of pol II CTD Ser2 and Tyr1 phosphorylation.

<p>(<b>A</b>) Myc epitope-tagged ICP22 and U_S1.5 were ectopically expressed in HeLa cells from a transfected expression vector containing the ICP22 open-reading frame followed by three Myc epitope tags. pcDNA3 was used as the control in this and all subsequent transfections. An anti-Myc tag antibody was used for the western blot analysis and the positions of full-length ICP22 and U_S1.5 are noted. α-tubulin was used as a loading control (<b>B</b>) Western blot analysis was performed as described in (A). The antibody used is indicated on the right. (<b>C</b>) Western blot analysis was carried out using antibodies to the CTD phosphorylation marks indicated on the right. CTCF was used as a loading control.