Gene‐specific requirement of RNA polymerase II CTD phosphorylation

SummaryThe largest subunit of RNA polymerase II, Rpb1, contains an unusual C‐terminal domain (CTD) composed of numerous repeats of the YSPTSPS consensus sequence. This sequence is the target of post‐translational modifications such as phosphorylation, glycosylation, methylation and transitions between stereoisomeric states, resulting in a vast combinatorial potential referred to as the CTD code. In order to gain insight into the biological significance of this code, several studies recently reported the genome‐wide distribution of some of these modified polymerases and associated factors in either fission yeast (Schizosaccharomyces pombe) or budding yeast (Saccharomyces cerevisiae). The resulting occupancy maps reveal that a general RNA polymerase II transcription complex exists and undergoes uniform transitions from initiation to elongation to termination. Nevertheless, CTD phosphorylation dynamics result in a gene‐specific effect on mRNA expression. In this review, we focus on the gene‐specific requirement of CTD phosphorylation and discuss in more detail the case of serine 2 phosphorylation (S2P) within the CTD, a modification that is dispensable for general transcription in fis