title: Hyper-phosphorylated retinoblastoma protein suppresses telomere elongation.
abstract: Immortalized cell lines maintain telomeres by the expression of telomerase or by a mechanism designated alternative lengthening of telomeres (ALT). Although DNA polymerase alpha (pol-alpha) is reported to be required for telomere maintenance, the critical role of pol-alpha in telomere maintenance has not been firmly determined. We examined the role of retinoblastoma protein (pRb) and pol-alpha in the regulation of telomere length, using telomere-fiber FISH. Telomere length varied dependent on the intracellular abundance of pol-alpha or pRb in HeLa cells. A proportion of hyper-phosphorylated pRb (ppRb) molecules localized to sites of telomeric DNA replication in HeLa cells. Pol-alpha might thus contribute to telomere maintenance, and might be regulated by ppRb.
authors.affiliation: Department of Biology, Faculty of Science, Tokyo University of Science (RIKADAI), Japan. takemura@rs.kagu.tus.ac.jp
authors.forename: Masaharu
authors.initials: M
authors.lastname: Takemura
authors.forename: Kazuto
authors.initials: K
authors.lastname: Sugimura
authors.forename: Katsuzumi
authors.initials: K
authors.lastname: Okumura
authors.forename: Siripan
authors.initials: S
authors.lastname: Limsirichaikul
authors.forename: Motoshi
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yoshiji
authors.initials: Y
authors.lastname: Yamada
authors.forename: Shonen
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000378:metabolism*; D016615:Telomere
chemical_list: D016160:Retinoblastoma Protein