title: The characterization of the TFIIIA synthesized in somatic cells of Xenopus laevis.
abstract: In somatic cells of Xenopus, transcription of the TFIIIA gene initiates greater than 200 bp upstream from the start site used in oocytes. The resultant mRNA encodes a protein, S-TFIIIA, that is 22 amino acids longer at its amino terminus than the abundant form of TFIIIA in oocytes (O-TFIIIA). S-TFIIIA binds the 5S RNA gene and 5S RNA, and both O- and S-TFIIIA promote the formation of stable transcription complexes on oocyte-type 5S RNA genes in an oocyte nuclear extract. We have not found any functional difference between the two forms of TFIIIA. Different transcription start sites suggest differential promoter usage--one in oocytes that permits high levels of gene activity and another that is used in somatic cells for low-level TFIIIA mRNA synthesis.
authors: Department of Embryology, Carnegie Institution of Washington, Baltimore, Maryland 21210.
authors: S H
authors: SH
authors: Kim
authors: M K
authors: MK
authors: Darby
authors: K E
authors: KE
authors: Joho
authors: D D
authors: DD
authors: Brown
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry; D012341:RNA, Ribosomal, 5S / Q000235:genetics; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014982:Xenopus laevis / Q000235:genetics*
chemical_list: D012333:RNA, Messenger; D012341:RNA, Ribosomal, 5S; D035582:Transcription Factor TFIIIA; D014157:Transcription Factors