Human telomerase RNA and box H/ACA scaRNAs share a common Cajal body-specific localization signal.
Telomerase is a ribonucleoprotein reverse transcriptase that uses its RNA component as a template for synthesis of telomeric DNA repeats at the ends of linear eukaryotic chromosomes. Here, fluorescence in situ hybridization demonstrates that in HeLa cancer cells, human telomerase RNA (hTR) accumulates in the nucleoplasmic Cajal bodies (CBs). Localization of transiently expressed hTR to CBs is supported by a short sequence motif (411-UGAG-414) that is located in the 3'-terminal box H/ACA RNA-like domain of hTR and that is structurally and functionally indistinguishable from the CB-specific localization signal of box H/ACA small CB-specific RNAs. In synchronized HeLa cells, hTR shows the most efficient accumulation in CBs during S phase, when telomeres are most likely synthesized. CBs may function in post-transcriptional maturation (e.g., cap hypermethylation of hTR), but they may also play a role in the assembly and/or function of telomerase holoenzyme.
Laboratoire de Biologie Moléculaire Eucaryote du CNRS, UMR5099, IFR109, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse, France.
Beáta E
BE
Jády
Edouard
E
Bertrand
Tamás
T
Kiss
D020816:Amino Acid Motifs; D002453:Cell Cycle / Q000502:physiology; D020541:Coiled Bodies / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D009690:Nucleic Acid Conformation; D021382:Protein Sorting Signals; D012313:RNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012315:RNA Caps; D020537:RNA, Small Nucleolar; D019098:Telomerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D021382:Protein Sorting Signals; D012315:RNA Caps; D020537:RNA, Small Nucleolar; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase