Document Detail


Coexistence of alternative lengthening of telomeres and telomerase in hTERT-transfected GM847 cells.
MedLine Citation:
PMID:  11359895     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
It has been shown previously that some immortalized human cells maintain their telomeres in the absence of significant levels of telomerase activity by a mechanism referred to as alternative lengthening of telomeres (ALT). Cells utilizing ALT have telomeres of very heterogeneous length, ranging from very short to very long. Here we report the effect of telomerase expression in the ALT cell line GM847. Expression of exogenous hTERT in GM847 (GM847/hTERT) cells resulted in lengthening of the shortest telomeres; this is the first evidence that expression of hTERT in ALT cells can induce telomerase that is active at the telomere. However, rapid fluctuation in telomere length still occurred in the GM847/hTERT cells after more than 100 population doublings. Very long telomeres and ALT-associated promyelocytic leukemia (PML) bodies continued to be generated, indicating that telomerase activity induced by exogenous hTERT did not abolish the ALT mechanism. In contrast, when the GM847 cell line was fused with two different telomerase-positive tumor cell lines, the ALT phenotype was repressed in each case. These hybrid cells were telomerase positive, and the telomeres decreased in length, very rapidly at first and then at the rate seen in telomerase-negative normal cells. Additionally, ALT-associated PML bodies disappeared. After the telomeres had shortened sufficiently, they were maintained at a stable length by telomerase. Together these data indicate that the telomerase-positive cells contain a factor that represses the ALT mechanism but that this factor is unlikely to be telomerase. Further, the transfection data indicate that ALT and telomerase can coexist in the same cells.
Authors:
K Perrem; L M Colgin; A A Neumann; T R Yeager; R R Reddel
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Molecular and cellular biology     Volume:  21     ISSN:  0270-7306     ISO Abbreviation:  Mol. Cell. Biol.     Publication Date:  2001 Jun 
Date Detail:
Created Date:  2001-05-21     Completed Date:  2001-06-28     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  8109087     Medline TA:  Mol Cell Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3862-75     Citation Subset:  IM    
Affiliation:
Cancer Research Group, Children's Medical Research Institute, Westmead, Sydney, New South Wales 2145, Australia.
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MeSH Terms
Descriptor/Qualifier:
Cell Line
Chromosomes, Human / genetics,  metabolism,  ultrastructure
DNA-Binding Proteins
Humans
Hybrid Cells
In Situ Hybridization, Fluorescence
RNA*
Telomerase / genetics*,  metabolism*
Telomere / genetics,  metabolism*,  ultrastructure
Transfection
Chemical
Reg. No./Substance:
0/DNA-Binding Proteins; 0/telomerase RNA; 63231-63-0/RNA; EC 2.7.7.49/Telomerase
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