title: TFIIIR is an isoleucine tRNA.
abstract: Promoter-specific transcription by silkworm RNA polymerase III is dependent on several transcription factors (TFs) in addition to the polymerase itself. The activities present in silk gland nuclear extracts that are necessary to reconstitute transcription from class III genes in vitro have been resolved into several partially purified components. These include TFIIIR, which is unusual because it is composed of RNA. Here, we identify the RNA that provides TFIIIR activity as silkworm tRNA(IleIAU). This conclusion is based on copurification of tRNA(IleIAU) with TFIIIR activity, TFIIIR activity in synthetic tRNA(Ile), and hybrid selection of TFIIIR activity by antisense tRNA(IleIAU). We have tested the ability of a variety of other tRNAs to stimulate transcription and find that TFIIIR activity is highly specific to silkworm tRNA(IleIAU).
authors.affiliation: Institute of Molecular Biology, University of Oregon, Eugene 97403.
authors.forename: H M
authors.initials: HM
authors.lastname: Dunstan
authors.forename: L S
authors.initials: LS
authors.lastname: Young
authors.forename: K U
authors.initials: KU
authors.lastname: Sprague
mesh_terms: D000818:Animals; D001483:Base Sequence; D012831:Bombyx / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002855:Chromatography, Thin Layer; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D005816:Genetic Complementation Test; D007700:Kinetics; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012320:RNA Polymerase III / Q000378:metabolism; D012355:RNA, Transfer, Ile / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000737:chemistry*; D019473:Transcription Factors, TFII; D014158:Transcription, Genetic
chemical_list: D012355:RNA, Transfer, Ile; D014157:Transcription Factors; D019473:Transcription Factors, TFII; C087356:transcription factor TFIIIR, Bombyx mori; D012320:RNA Polymerase III