The yeast capping enzyme represses RNA polymerase II transcription.
Using a highly pure transcription system derived from Saccharomyces cerevisiae, we have purified an activity in yeast whole-cell extracts that represses RNA polymerase II transcription. Mechanistic studies suggest that this repressor specifically targets transcriptional reinitiation. The two polypeptides that constitute the repressor have been identified as Ceg1p and Cet1p, the two subunits of the yeast pre-mRNA capping enzyme. A purified recombinant capping enzyme is able to reconstitute repressor activity. Cet1p is necessary for and capable of this repression. Transcriptional run-on experiments indicate that the capping enzyme also serves as a repressor in vivo. Efficient pre-mRNA capping relies on interactions between the capping enzyme and transcription apparatus. Repression by the capping enzyme suggests a bidirectional flow of information between capping and transcription.
Myers
Lawrence C
LC
Department of Biochemistry, Dartmouth Medical School, Hanover, NH 03755, USA. larry.myeers@dartmouth.edu
Lacomis
Lynne
L
Erdjument-Bromage
Hediye
H
Tempst
Paul
P
D017766:Acid Anhydride Hydrolases / Q000302:isolation & purification / Q000378:metabolism*; D002852:Chromatography, Ion Exchange; D015966:Gene Expression Regulation, Fungal; D013058:Mass Spectrometry; D008957:Models, Genetic; D009713:Nucleotidyltransferases / Q000302:isolation & purification / Q000378:metabolism*; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D012097:Repressor Proteins / Q000302:isolation & purification / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000302:isolation & purification / Q000378:metabolism; D014158:Transcription, Genetic; D000098556:mRNA Guanylyltransferases
D011994:Recombinant Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D009713:Nucleotidyltransferases; D012319:RNA Polymerase II; D000098556:mRNA Guanylyltransferases; D017766:Acid Anhydride Hydrolases; C023090:RNA triphosphatase