title: Asparagales telomerases which synthesize the human type of telomeres.
abstract: The order of monocotyledonous plants Asparagales is attractive for studies of telomere evolution as it includes three phylogenetically distinct groups with telomeres composed of TTTAGGG (Arabidopsis-type), TTAGGG (human-type) and unknown alternative sequences, respectively. To analyze the molecular causes of these switches in telomere sequence (synthesis), genes coding for the catalytic telomerase subunit (TERT) of representative species in the first two groups have been cloned. Multiple alignments of the sequences, together with other TERT sequences in databases, suggested candidate amino acid substitutions grouped in the Asparagales TERT synthesizing the human-type repeat that could have contributed to the changed telomere sequence. Among these, mutations in the C motif are of special interest due to its functional importance in TERT. Furthermore, two different modes of initial elongation of the substrate primer were observed in Asparagales telomerases producing human-like repeats, which could be attributed to interactions between the telomerase RNA subunit (TR) and the substrate.
authors.affiliation: Laboratory of DNA-Molecular Complexes, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, Brno, CZ-61265, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Sýkorová
authors.forename: Andrew Rowland
authors.initials: AR
authors.lastname: Leitch
authors.forename: Jirí
authors.initials: J
authors.lastname: Fajkus
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D019684:Magnoliopsida / Q000201:enzymology / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism; D016615:Telomere / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D004268:DNA-Binding Proteins; C509186:TERT protein, human; D019098:Telomerase