Phosphorylation of the RNA polymerase II carboxy-terminal domain by the Bur1 cyclin-dependent kinase.
BUR1, which was previously identified by a selection for mutations that have general effects on transcription in Saccharomyces cerevisiae, encodes a cyclin-dependent kinase that is essential for viability, but none of its substrates have been identified to date. Using an unbiased biochemical approach, we have identified the carboxy-terminal domain (CTD) of Rpb1, the largest subunit of RNA polymerase II, as a Bur1 substrate. Phosphorylation of Rpb1 by Bur1 is likely to be physiologically relevant, since bur1 mutations interact genetically with rpb1 CTD truncations and with mutations in other genes involved in CTD function. Several genetic interactions are presented, implying a role for Bur1 during transcriptional elongation. These results identify Bur1 as a fourth S. cerevisiae CTD kinase and provide striking functional similarities between Bur1 and metazoan P-TEFb.
Murray
S
S
Department of Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Udupa
R
R
Yao
S
S
Hartzog
G
G
Prelich
G
G
D000818:Animals; D018844:Cyclin-Dependent Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D015151:Immunoblotting; D010455:Peptides / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D011233:Precipitin Tests; D011494:Protein Kinases; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D012319:RNA Polymerase II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013379:Substrate Specificity; D014158:Transcription, Genetic / Q000235:genetics
C118305:CTDK-I protein complex, S cerevisiae; D010455:Peptides; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D018844:Cyclin-Dependent Kinases; C414163:SGV1 protein, S cerevisiae; D012319:RNA Polymerase II