title: Reconstitution of yeast and Arabidopsis RNA polymerase alpha-like subunit heterodimers.
abstract: Two subunits of about 36-44 kDa and 13-19 kDa in the eukaryotic nuclear RNA polymerases share limited amino acid sequence similarity to the alpha subunit in Escherichia coli RNA polymerase. The alpha subunit in the prokaryotic enzyme has a stoichiometry of 2, but the stoichiometry of the alpha-like subunits in the eukaryotic enzymes is not entirely clear. To gain insight into the subunit stoichiometry and assembly pathway for eukaryotic RNA polymerases, in vitro reconstitution experiments have been carried out with recombinant alpha-like subunits from yeast and plant RNA polymerase II. The large and small alpha-like subunits from each species formed stable heterodimers in vitro, but neither the large or small alpha-like subunits formed stable homodimers. Furthermore, mixed heterodimers were formed between corresponding subunits of yeast and plants, but were not formed between corresponding subunits in different RNA polymerases from the same species. Our results suggest that RNA polymerase II alpha-like heterodimers may be the equivalent of alpha homodimers found in E. coli RNA polymerase.
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Larkin
authors.forename: T J
authors.initials: TJ
authors.lastname: Guilfoyle
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D002846:Chromatography, Affinity; D004926:Escherichia coli / Q000201:enzymology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011487:Protein Conformation; D012318:RNA Polymerase I / Q000378:metabolism; D012319:RNA Polymerase II / Q000378:metabolism*; D012320:RNA Polymerase III / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D012319:RNA Polymerase II; D012318:RNA Polymerase I; D012320:RNA Polymerase III