title: Effects on telomerase activity of the 5'-terminal region of human telomerase RNA.
abstract: Human telomerase RNA (hTR) is assumed to contain a 17-nt segment in a single-stranded state at the 5'-terminus. There are four stretches of consecutive G residues, which are apt to form a quadruplex structure, in the segment. It is reported that deletion of some part of this region enhances telomerase activity when the core telomerase enzyme is reconstituted by addition of telomerase reverse transcriptase. To elucidate the reason for such effects, we constructed hTR mutants with deletion of the segment (hTRdelta20) and with the segment containing four G-to-A displacement to interrupt the G-stretch sequences (hTR17A) and their activity was compared with that of the wild-type hTR (hTRW). hTRdelta20 showed much higher activity than the other while hTR17A showed activity similar to that of hTRW. This result suggests that the lower activity for full-length hTR is not due to putative quadruplex formation.
authors.affiliation: Department of Environment and Natural Sciences, Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, YoKohama 240-8501, Japan.
authors.forename: Xianglan
authors.initials: X
authors.lastname: Li
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Nishizuka
authors.forename: Kota
authors.initials: K
authors.lastname: Tsutsumi
authors.forename: Yuka
authors.initials: Y
authors.lastname: Imai
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kurihara
authors.forename: Seiichi
authors.initials: S
authors.lastname: Uesugi
mesh_terms: D001483:Base Sequence; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012313:RNA / Q000737:chemistry* / Q000378:metabolism; D017384:Sequence Deletion; D019098:Telomerase / Q000737:chemistry* / Q000378:metabolism*
chemical_list: C422952:telomerase RNA; D012313:RNA; C509186:TERT protein, human; D019098:Telomerase