title: Structure, interactions and effects on activity of the 5'-terminal region of human telomerase RNA.
abstract: Telomerase is an enzyme that catalyzes addition of telomeric repeat sequences to the 3'-termini of eukaryotic chromosome DNA. The catalytic core of telomerase consists of a protein component, telomerase reverse transcriptase (TERT), for the catalysis and an RNA component, telomerase RNA (TR), containing the template for the sequence. Human telomerase RNA (hTR) consists of 451 nucleotides (nt) and contains consecutive G-stretches in the 5'-terminal region. We examined the effects of the 5'-terminal sequence (nt 1-17) in hTR, which is assumed to be a single-stranded region (region 1), on interaction and telomerase activity in vitro. Mutation and binding experiments for hTR and its variants suggest that region 1 has repressive effects on telomerase activity by interaction with the region(s) in the 3'-half part. We prepared various hTR variants with mutations in region 1 and two possible target regions (region 2: nt 229-244; region 3: nt 284-297). Studies on these variants showed that region 1 can interact with regions 2 and 3 and the interactions between regions 1 and 3 may contribute to the repressive effects of region 1. We found that a mutation in region 2 markedly enhances telomerase activity. We also found that some deletion and sequence mutations in region 1 enhance the activity.
authors: 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: Xianglan
authors: X
authors: Li
authors: Hidetoshi
authors: H
authors: Nishizuka
authors: Kota
authors: K
authors: Tsutsumi
authors: Yuka
authors: Y
authors: Imai
authors: Yasuyuki
authors: Y
authors: Kurihara
authors: Seiichi
authors: S
authors: Uesugi
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry; D016373:DNA, Antisense / Q000494:pharmacology; D024202:Electrophoretic Mobility Shift Assay; D054856:G-Quadruplexes; D006147:Guanine / Q000737:chemistry; D006801:Humans; D009154:Mutation; D012313:RNA / Q000737:chemistry* / Q000235:genetics; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism
chemical_list: D016373:DNA, Antisense; D006147:Guanine; D012313:RNA; D004247:DNA; D019098:Telomerase