Oca2 of Schizosaccharomyces pombe Regulates Pol II Transcriptional Termination

We describe a Schizosaccharomyces pombe protein kinase, Oca2, which is involved in transcription termination of a subset of genes. Lack of Oca2 results the accumulation of Pol II over termination regions. Oca2 phosphorylates S. pombe homologue of Ctk2, the putative cyclin subunit of fission yeast Ctk1, in vitro. In S. cerevisae, Ctk1 phosphorylates serine 2 of the CTD of RNA polymerase II (Pol II), a modification associated with transcriptional elongation, termination and co-transcriptional pre-mRNA processing. Both, Oca2 and Ctk2 localize predominantly to terminator regions, and in oca2Δ cells Ctk2 localization to terminators is lost. Oca2 mediated recruitment of Ctk2 may be a prerequisite for correct Pol II release from certain termination sites.