title: Ssu72 phosphatase-dependent erasure of phospho-Ser7 marks on the RNA polymerase II C-terminal domain is essential for viability and transcription termination.
abstract: The C-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) serves an important role in coordinating stage-specific recruitment and release of cellular machines during transcription. Dynamic placement and removal of phosphorylation marks on different residues of a repeating heptapeptide (YSPTSPS) of the CTD underlies the engagement of relevant cellular machinery. Whereas sequential placement of phosphorylation marks is well explored, genome-wide engagement of phosphatases that remove these CTD marks is poorly understood. In particular, identifying the enzyme that erases phospho-Ser7 (Ser7-P) marks is especially important, because we find that substituting this residue with a glutamate, a phospho-mimic, is lethal. Our observations implicate Ssu72 as a Ser7-P phosphatase. We report that removal of all phospho-CTD marks during transcription termination is mechanistically coupled. An inability to remove these marks prevents Pol II from terminating efficiently and will likely impede subsequent assembly into the pre-initiation complex.
authors.affiliation: Department of Biochemistry and The Genome Center, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Zhang
authors.forename: Amber L
authors.initials: AL
authors.lastname: Mosley
authors.forename: Sreenivasa R
authors.initials: SR
authors.lastname: Ramisetty
authors.forename: Juan B
authors.initials: JB
authors.lastname: Rodríguez-Molina
authors.forename: Michael P
authors.initials: MP
authors.lastname: Washburn
authors.forename: Aseem Z
authors.initials: AZ
authors.lastname: Ansari
mesh_terms: D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D020125:Mutation, Missense; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012319:RNA Polymerase II / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D039221:mRNA Cleavage and Polyadenylation Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C416934:SSU72 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D039221:mRNA Cleavage and Polyadenylation Factors; D012694:Serine; D012319:RNA Polymerase II; D010749:Phosphoprotein Phosphatases