Hyper-phosphorylated retinoblastoma protein suppresses telomere elongation.
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.
Takemura
Masaharu
M
Department of Biology, Faculty of Science, Tokyo University of Science (RIKADAI), Japan. takemura@rs.kagu.tus.ac.jp
Sugimura
Kazuto
K
Okumura
Katsuzumi
K
Limsirichaikul
Siripan
S
Suzuki
Motoshi
M
Yamada
Yoshiji
Y
Yoshida
Shonen
S
D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000378:metabolism*; D016615:Telomere
D016160:Retinoblastoma Protein