A Gene-Specific Requirement of RNA Polymerase II CTD Phosphorylation for Sexual Differentiation in S. pombe

Abstract

Thus, the S2P polymerase plays a specific, regulatory role in cell differentiation through the induction of ste11.

Punctuation and syntax of the RNA polymerase II CTD code in fission yeast

“…1B). We also constructed a CTD composed of nine tandem copies of a 12-mer element, (YSPTSPSYSPAA) 9 , and found that this CTD sustained apparently normal growth at all temperatures (Fig. 1B) The minimal coding decapeptide brackets two Pro3 and Ser5 residues.…”

RNA Polymerase II transcription elongation and Pol II CTD Ser2 phosphorylation

“…While an overwhelming majority of detectable Ser2-P is absent with loss of activity of the Ctk1 homolog, Lsk1, 36,41 recent data using analog sensitive mutants has also shown that fission yeast Cdk9 is responsible for some level of Ser2-P. [41][42][43] Regulation of yeast Ser2 kinases Mirroring their roles in Ser2 phosphorylation, both Ctk1 and Bur1 are associated with elongating Pol II by chromatin immunoprecipitation (ChIP), 32,44,45 and this has been shown genome wide for Ctk1. 46 In yeast, these kinases appear to be recruited to loci through general mechanisms, rather than genespecific factors.…”

Individual letters of the RNA polymerase II CTD code govern distinct gene expression programs in fission yeast

“…The latter scenario applies to the Ser2 coding letter, insofar as a heterothallic haploid fission yeast rpb1-S2A mutant can grow vegetatively, but is unable to mate with heterothallic WT cells of either mating type, i.e., S2A is sterile. Sterility results from the inability of S2A cells to induce expression of the Ste11 transcription factor that triggers the meiotic sexual differentiation pathway (5,6,8). Microarray analyses of the transcriptome of S2A cells vs. WT highlighted ≥1.5-fold changes in the expression level of many meiotically regulated genes (5,9).…”

“…Sterility results from the inability of S2A cells to induce expression of the Ste11 transcription factor that triggers the meiotic sexual differentiation pathway (5,6,8). Microarray analyses of the transcriptome of S2A cells vs. WT highlighted ≥1.5-fold changes in the expression level of many meiotically regulated genes (5,9). The Ser2 requirement for transcription during sexual differentiation was bypassed by subtracting Ser7, suggesting that imbalance in the phosphorylation array, not absence of a CTD-PO 4 cue, underlies a CTD-associated pathology (6).…”

“…Basic informational rules that govern the CTD code have been elucidated by genetically manipulating the composition and structure of the Rpb1 CTD in the fission yeast Schizosaccharomyces pombe (3)(4)(5)(6)(7). By introducing alanines and conservative mutations in lieu of Tyr1, Ser2, Pro3, Thr4, Ser5, Pro6, and Ser7 of every consensus heptad of a fully functional Rpb1 CTD array (comprising 14 consensus heptad repeats linked to the body of Rpb1 by a "rump" consisting of four degenerate heptads), we determined that: (i) Tyr1, Pro3, Ser5, and Pro6 are essential for viability, by the criterion that alanine substitution is lethal, whereas Ser2, Thr4, and Ser7 are not essential; and (ii) Y1F, S2A•S7A and T4A•S7A mutants are viable, signifying that phenylalanine is functional in lieu of Tyr1 and that Ser5 is the only strictly essential phosphorylation site in fission yeast (6).…”