The characterization of the TFIIIA synthesized in somatic cells of Xenopus laevis

• Published in: Genes & development Vol. 4; no. 9; pp. 1602 - 1610
• Main Authors: SANG HEE KIM, DARBY, M. K, JOHO, K. E, BROWN, D. D
• Format: Journal Article
• Language: English
• Published: Cold Spring Harbor, NY Cold Spring Harbor Laboratory 01.09.1990
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Gene expression; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Oocytes - metabolism; Protein Biosynthesis - genetics; RNA, Messenger - chemistry; RNA, Ribosomal, 5S - genetics; Transcription Factor TFIIIA; Transcription Factors - genetics; Transcription, Genetic; Xenopus laevis; Xenopus laevis - genetics; In vitro transcription; In vitro translation; Nucleotide sequence; Zinc finger structure; Xenopus laevis; Amphibia; Somatic cell; Salientia; Gene expression; Northern blotting; Vertebrata; Messenger RNA; Gene; Immunoblotting assay; Molecular cloning; Southern blotting; Comparative study; Oocyte
• ISSN: 0890-9369; 1549-5477
• DOI: 10.1101/gad.4.9.1602

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.