title: Splicing inhibition decreases phosphorylation level of Ser2 in Pol II CTD.
abstract: Phosphorylation of the C-terminal domain of the largest subunit of RNA polymerase II (Pol II), especially Ser2 and Ser5 residues, plays important roles in transcription and mRNA processing, including 5' end capping, splicing and 3' end processing. These phosphorylation events stimulate mRNA processing, however, it is not clear whether splicing activity affects the phosphorylation status of Pol II. In this study, we found that splicing inhibition by potent splicing inhibitors spliceostatin A (SSA) and pladienolide B or by antisense oligos against snRNAs decreased phospho-Ser2 level, but had little or no effects on phospho-Ser5 level. In contrast, transcription and translation inhibitors did not decrease phospho-Ser2 level, therefore inhibition of not all the gene expression processes cause the decrease of phospho-Ser2. SSA treatment caused early dissociation of Pol II and decrease in phospho-Ser2 level of chromatin-bound Pol II, suggesting that splicing inhibition causes downregulation of phospho-Ser2 through at least these two mechanisms.
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Koga
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, Toyama 930-0194, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Hayashi
authors.affiliation: Frontier Research Core for Life Sciences, University of Toyama, Toyama 930-0194, Japan kaida@med.u-toyama.ac.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kaida
mesh_terms: D002843:Chromatin / Q000378:metabolism; D015536:Down-Regulation; D006367:HeLa Cells; D006801:Humans; D016376:Oligonucleotides, Antisense; D010766:Phosphorylation; D042925:Positive Transcriptional Elongation Factor B / Q000037:antagonists & inhibitors; D017434:Protein Structure, Tertiary; D011714:Pyrans / Q000494:pharmacology; D012319:RNA Polymerase II / Q000737:chemistry / Q000378:metabolism*; D012326:RNA Splicing / Q000187:drug effects; D012342:RNA, Small Nuclear / Q000037:antagonists & inhibitors; D012694:Serine / Q000378:metabolism*; D013141:Spiro Compounds / Q000494:pharmacology
chemical_list: D002843:Chromatin; D016376:Oligonucleotides, Antisense; D011714:Pyrans; D012342:RNA, Small Nuclear; D013141:Spiro Compounds; C553684:spliceostatin A; D012694:Serine; D042925:Positive Transcriptional Elongation Factor B; D012319:RNA Polymerase II