title: Identification and analyses of the Xenopus TERT gene that encodes the catalytic subunit of telomerase.
abstract: The Xenopus telomerase catalytic component gene, xTERT (Xenopus telomerase reverse transcriptase), has been cloned. The production of xTERT recombinant protein together with the proposed Xenopus telomerase RNA (xTR) (Chen et al., 2000. Cell 100, 503-514) in a rabbit reticulocyte lysate system led to the reconstitution of active telomerase, indicating that both products are functional telomerase components. Both xTERT expression and telomerase activity are high from the early to the late blastula stage. However, they are decreased at the gastrula stage and thereafter, suggesting that the xTERT expression level is the primary mechanism for regulating telomerase activity in Xenopus development. This is the first report of a non-mammalian vertebrate TERT gene. Sequence comparison of xTERT with human and mouse TERTs has uncovered four regions conserved in the amino-terminal halves of vertebrate TERT proteins, the functions of which will be discussed herein.
authors.affiliation: Laboratory of Molecular and Cellular Assembly, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8501, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kuramoto
authors.forename: K
authors.initials: K
authors.lastname: Ohsumi
authors.forename: T
authors.initials: T
authors.lastname: Kishimoto
authors.forename: F
authors.initials: F
authors.lastname: Ishikawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D002460:Cell Line; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004268:DNA-Binding Proteins; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D008969:Molecular Sequence Data; D012313:RNA / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D019098:Telomerase / Q000235:genetics*; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D012313:RNA; C509186:TERT protein, human; D019098:Telomerase; C509187:Tert protein, mouse