TY - JOUR
T1 - Human Cancer Cells Harbor T-Stumps, a Distinct Class of Extremely Short Telomeres
AU - Xu, Lifeng
AU - Blackburn, Elizabeth H.
PY - 2007/10/26
Y1 - 2007/10/26
N2 - Using a modified single telomere length analysis protocol (STELA) to clone and examine the sequence composition of individual human XpYp telomeres, we discovered a distinct class of extremely short telomeres in human cancer cells with active telomerase. We name them "t-stumps," to distinguish them from the well-regulated longer bulk telomeres. T-stumps contained arrangements of telomeric repeat variants and a minimal run of seven canonical telomeric TTAGGG repeats, but all could bind at least one TRF1 or TRF2 in vitro. The abundance of t-stumps was unaffected by ATM alteration but could be changed by manipulating telomerase catalytic subunit (hTERT) levels in cancer cells. We propose that in the setting of active telomerase and compromised checkpoints characteristic of human cancer cells, t-stumps define the minimal telomeric unit that can still be protected by a TRF1/TRF2-capping complex and, further, that hTERT (or telomerase) may have a role in protecting t-stumps.
AB - Using a modified single telomere length analysis protocol (STELA) to clone and examine the sequence composition of individual human XpYp telomeres, we discovered a distinct class of extremely short telomeres in human cancer cells with active telomerase. We name them "t-stumps," to distinguish them from the well-regulated longer bulk telomeres. T-stumps contained arrangements of telomeric repeat variants and a minimal run of seven canonical telomeric TTAGGG repeats, but all could bind at least one TRF1 or TRF2 in vitro. The abundance of t-stumps was unaffected by ATM alteration but could be changed by manipulating telomerase catalytic subunit (hTERT) levels in cancer cells. We propose that in the setting of active telomerase and compromised checkpoints characteristic of human cancer cells, t-stumps define the minimal telomeric unit that can still be protected by a TRF1/TRF2-capping complex and, further, that hTERT (or telomerase) may have a role in protecting t-stumps.
KW - SIGNALING
UR - http://www.scopus.com/inward/record.url?scp=35349023061&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=35349023061&partnerID=8YFLogxK
U2 - 10.1016/j.molcel.2007.10.005
DO - 10.1016/j.molcel.2007.10.005
M3 - Article
C2 - 17964269
AN - SCOPUS:35349023061
VL - 28
SP - 315
EP - 327
JO - Molecular Cell
JF - Molecular Cell
SN - 1097-2765
IS - 2
ER -