title: Telomere- and telomerase-interacting protein that unfolds telomere G-quadruplex and promotes telomere extension in mammalian cells.
abstract: Telomere extension by telomerase is essential for chromosome stability and cell vitality. Here, we report the identification of a splice variant of mammalian heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2), hnRNP A2*, which binds telomeric DNA and telomerase in vitro. hnRNP A2* colocalizes with telomerase in Cajal bodies and at telomeres. In vitro assays show that hnRNP A2* actively unfolds telomeric G-quadruplex DNA, exposes 5 nt of the 3' telomere tail and substantially enhances the catalytic activity and processivity of telomerase. The expression level of hnRNP A2* in tissues positively correlates with telomerase activity, and overexpression of hnRNP A2* leads to telomere elongation in vivo. Thus, hnRNP A2* plays a positive role in unfolding telomere G-quadruplexes and in enhancing telomere extension by telomerase.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology,  Chinese Academy of Sciences, Beijing 100101,  People's Republic of China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Ming-liang
authors.initials: ML
authors.lastname: Tang
authors.forename: Zhi-xiong
authors.initials: ZX
authors.lastname: Zeng
authors.forename: Ren-yi
authors.initials: RY
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Xue
authors.forename: Yu-hua
authors.initials: YH
authors.lastname: Hao
authors.forename: Dai-wen
authors.initials: DW
authors.lastname: Pang
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Zheng
authors.initials: Z
authors.lastname: Tan
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054856:G-Quadruplexes; D006367:HeLa Cells; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008954:Models, Biological; D009690:Nucleic Acid Conformation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019098:Telomerase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism*; D059505:Telomere Homeostasis / Q000502:physiology*
chemical_list: D018076:DNA, Complementary; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C439768:hnRNP A2; D019098:Telomerase