title: Purification and characterization of yeast RNA polymerase II general initiation factor g.
abstract: Yeast RNA polymerase II general initiation factor g was purified to near homogeneity on the basis of its function in a reconstituted transcription system. Polypeptides of 30, 54, and 105 kDa co-purified with transcriptional activity, forming a complex with a mass of 300 kDa as judged by gel filtration, but only 100 kDa based on sedimentation in glycerol gradients, suggesting an elongated shape. Transcription activity could be reconstituted after separation of the three polypeptides under denaturing conditions; the 54- and 105-kDa subunits were both essential, while the 30-kDa subunit was slightly stimulatory. Factor g was required for initiation at all promoters tested, including those from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and adenovirus. Factor g can stably associate with RNA polymerase II, as shown by cosedimentation in a glycerol gradient.
authors.affiliation: Department of Cell Biology, Stanford University School of Medicine, California 94305.
authors.forename: N L
authors.initials: NL
authors.lastname: Henry
authors.forename: M H
authors.initials: MH
authors.lastname: Sayre
authors.forename: R D
authors.initials: RD
authors.lastname: Kornberg
mesh_terms: D002845:Chromatography; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D017886:Durapatite; D006882:Hydroxyapatites; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D012319:RNA Polymerase II / Q000302:isolation & purification* / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D014157:Transcription Factors / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D006882:Hydroxyapatites; D046911:Macromolecular Substances; D014157:Transcription Factors; D017886:Durapatite; D012319:RNA Polymerase II