RNA emerging from the active site of RNA polymerase II interacts with the Rpb7 subunit.
Structural studies of RNA polymerase II have suggested two possible exit paths for the nascent RNA: groove 1, which points toward the subcomplex of subunits Rpb4 and Rpb7, and groove 2, which points toward Rpb8. These alternatives could not be distinguished previously because less than 10 nucleotides (nt) of transcript were resolved in the structures. We have approached this question by UV cross-linking nascent RNA to components of the transcription complex through uridine analogs located within the first six nucleotides of the RNA. We find that the emerging transcript cross-links to the Rpb7 subunit of RNA polymerase II in various complexes containing 26- to 32-nt transcripts. This interaction is greatly reduced in complexes with 41- or 43-nt RNAs and absent when the transcript is 125 nt. Our results are consistent with groove 1 being the exit path for nascent RNA.
Ujvári
Andrea
A
Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Luse
Donal S
DS
D001483:Base Sequence; D001665:Binding Sites; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012319:RNA Polymerase II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism; D000072668:Splicing Factor U2AF; D014158:Transcription, Genetic / Q000235:genetics
D009687:Nuclear Proteins; D021122:Protein Subunits; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D000072668:Splicing Factor U2AF; C000607494:U2AF2 protein, human; C477608:POLR2G protein, human; D012319:RNA Polymerase II