Functional interaction of Rpb1 and Spt5 C-terminal domains in co-transcriptional histone modification.
Transcription by RNA polymerase II (RNAPII) is accompanied by a conserved pattern of histone modifications that plays important roles in regulating gene expression. The establishment of this pattern requires phosphorylation of both Rpb1 (the largest RNAPII subunit) and the elongation factor Spt5 on their respective C-terminal domains (CTDs). Here we interrogated the roles of individual Rpb1 and Spt5 CTD phospho-sites in directing co-transcriptional histone modifications in the fission yeast Schizosaccharomyces pombe. Steady-state levels of methylation at histone H3 lysines 4 (H3K4me) and 36 (H3K36me) were sensitive to multiple mutations of the Rpb1 CTD repeat motif (Y1S2P3T4S5P6S7). Ablation of the Spt5 CTD phospho-site Thr1 reduced H3K4me levels but had minimal effects on H3K36me. Nonetheless, Spt5 CTD mutations potentiated the effects of Rpb1 CTD mutations on H3K36me, suggesting overlapping functions. Phosphorylation of Rpb1 Ser2 by the Cdk12 orthologue Lsk1 positively regulated H3K36me but negatively regulated H3K4me. H3K36me and histone H2B monoubiquitylation required Rpb1 Ser5 but were maintained upon inactivation of Mcs6/Cdk7, the major kinase for Rpb1 Ser5 in vivo, implicating another Ser5 kinase in these regulatory pathways. Our results elaborate the CTD 'code' for co-transcriptional histone modifications.
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
Jean
J
Mbogning
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
Viviane
V
Pagé
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
Jillian
J
Burston
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
Emily
E
Schwenger
Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
Robert P
RP
Fisher
Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY 10065, USA.
Beate
B
Schwer
Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
Stewart
S
Shuman
Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, H3G 1Y6, Canada jason.tanny@mcgill.ca.
Jason C
JC
Tanny
D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D008745:Methylation; D009154:Mutation; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000095043:Cyclin-Dependent Kinase-Activating Kinase
D006657:Histones; D029702:Schizosaccharomyces pombe Proteins; C549622:Spt5 protein, S pombe; D035602:Transcriptional Elongation Factors; D012694:Serine; D018844:Cyclin-Dependent Kinases; C501735:Lsk1 protein, S pombe; D012319:RNA Polymerase II; C000606154:Rpb1 protein, S pombe; D000095043:Cyclin-Dependent Kinase-Activating Kinase