Cell cycle-regulated trafficking of human telomerase to telomeres.
Telomerase synthesizes telomeres at the ends of human chromosomes during S phase. The results presented here suggest that telomerase activity may be regulated by intranuclear trafficking of the key components of the enzyme in human cells. We examined the subcellular localization of endogenous human telomerase RNA (hTR) and telomerase reverse transcriptase (hTERT) in HeLa cervical carcinoma cells. Throughout most of the cell cycle, we found that the two essential components of telomerase accumulate at intranuclear sites separate from telomeres. However, during S phase, both hTR and hTERT are specifically recruited to subsets of telomeres. The localization of telomerase to telomeres is dynamic, peaking at mid-S phase. We also found complex associations of both hTR and hTERT with nucleoli and Cajal bodies during S phase, implicating both structures in the biogenesis and trafficking of telomerase. Our results mark the first observation of human telomerase at telomeres and provide a mechanism for the cell cycle-dependent regulation of telomere synthesis in human cells.
Tomlinson
Rebecca L
RL
Departments of Biochemistry and Molecular Biology and Genetics, University of Georgia, Athens, GA 30602, USA.
Ziegler
Tania D
TD
Supakorndej
Teerawit
T
Terns
Rebecca M
RM
Terns
Michael P
MP
D002453:Cell Cycle / Q000502:physiology*; D002466:Cell Nucleolus / Q000201:enzymology / Q000648:ultrastructure; D020541:Coiled Bodies / Q000737:chemistry / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000032:analysis / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D021381:Protein Transport; D012313:RNA; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated / Q000032:analysis / Q000378:metabolism*; D016196:S Phase / Q000502:physiology; D019098:Telomerase / Q000032:analysis / Q000378:metabolism*; D016615:Telomere / Q000378:metabolism* / Q000648:ultrastructure
D004268:DNA-Binding Proteins; D062085:RNA, Long Noncoding; D022661:RNA, Untranslated; C422952:telomerase RNA; D012313:RNA; D019098:Telomerase