Abstract
The human telomerase RNA (hTR), together with the telomerase reverse transcriptase, hTERT, constitute the core components of telomerase that is essential for telomere maintenance. While hTR is ubiquitously expressed, hTERT is normally restricted to germ cells and certain stem cells, but both are often deregulated during tumorigenesis. Here, we investigated the effects of changes in hTR cellular levels. Surprisingly, while inhibition of hTR expression triggers a rapid, telomerase-independent, growth arrest associated with p53 and CHK1 activation, its increased expression neutralizes activation of these pathways in response to genotoxic stress. These hTR effects are mediated through ATR and are sufficiently strong to impair ATR-mediated DNA-damage checkpoint responses. Furthermore, in response to low UV radiation, which activates ATR, endogenous hTR levels increase irrespective of telomerase status. Thus, we uncovered a novel, telomerase-independent, function of hTR that restrains ATR activity and participates in the recovery of cells from UV radiation.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Ataxia Telangiectasia Mutated Proteins
-
Cell Cycle / genetics
-
Cell Cycle / radiation effects
-
Cell Cycle Proteins / antagonists & inhibitors
-
Cell Cycle Proteins / metabolism*
-
Cell Division / genetics
-
Cell Division / radiation effects
-
Cell Line
-
Cell Line, Tumor
-
Checkpoint Kinase 1
-
G2 Phase / genetics
-
G2 Phase / radiation effects
-
Growth Inhibitors / physiology
-
Humans
-
Protein Kinases / physiology
-
Protein Serine-Threonine Kinases / antagonists & inhibitors
-
Protein Serine-Threonine Kinases / metabolism*
-
RNA / physiology*
-
Signal Transduction / genetics
-
Signal Transduction / radiation effects
-
Telomerase / antagonists & inhibitors
-
Telomerase / biosynthesis
-
Telomerase / genetics
-
Telomerase / physiology*
-
Tumor Suppressor Protein p53 / physiology
-
Ultraviolet Rays
Substances
-
Cell Cycle Proteins
-
Growth Inhibitors
-
Tumor Suppressor Protein p53
-
telomerase RNA
-
RNA
-
Protein Kinases
-
ATR protein, human
-
Ataxia Telangiectasia Mutated Proteins
-
CHEK1 protein, human
-
Checkpoint Kinase 1
-
Protein Serine-Threonine Kinases
-
Telomerase