Document Detail


Replicative senescence in sheep fibroblasts is a p53 dependent process.
MedLine Citation:
PMID:  15664728     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Studies on telomere and telomerase biology are fundamental to the understanding of human ageing, and age-related diseases such as cancer. However, human studies are hampered by the lack of fully reflective animal model systems. Here we describe basic studies of telomere length and telomerase activity in sheep tissues and cells. Terminal restriction fragment lengths from sheep tissues ranged from 9 to 23 kb, with telomerase activity present in testis but suppressed in somatic tissues. Sheep fibroblasts had a finite lifespan in culture, after which the cells entered senescence. During in vitro growth the mean terminal restriction fragment lengths decreased in size at a rate of 210 and 350 bp per population doubling (PD). Senescent skin fibroblasts had increased levels of p53 and p21WAF1 compared to young cells. Incubation of senescent cells with siRNA duplexes specific for p53 suppressed p53 expression and allowed the cells to re-enter the cell cycle. Five PDs beyond senescence the siRNA-treated cells reached a second proliferative barrier. This study shows that telomere biology in sheep is similar to that in humans, with senescence in sheep GM03550 fibroblasts being a telomere-driven, p53-(p21WAF1)-dependent process. Therefore sheep may represent an alternative model system for studying telomere biology, replicative senescence, and by implication human ageing.
Authors:
Terence Davis; Julia W Skinner; Richard G A Faragher; Christopher J Jones; David Kipling
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Experimental gerontology     Volume:  40     ISSN:  0531-5565     ISO Abbreviation:  Exp. Gerontol.     Publication Date:    2005 Jan-Feb
Date Detail:
Created Date:  2005-01-24     Completed Date:  2005-05-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0047061     Medline TA:  Exp Gerontol     Country:  England    
Other Details:
Languages:  eng     Pagination:  17-26     Citation Subset:  IM    
Affiliation:
Department of Pathology, School of Medicine, University of Cardiff, Heath Park, Cardiff CF14 4XN, Wales, UK.
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MeSH Terms
Descriptor/Qualifier:
Animals
Cell Aging / genetics*
Cell Cycle Proteins / metabolism
Cell Division / genetics
Cell Line
Cyclin-Dependent Kinase Inhibitor p21
Fibroblasts / cytology,  metabolism*
Models, Animal
RNA, Small Interfering / genetics
Sheep
Telomerase / metabolism
Telomere
Tumor Suppressor Protein p53 / metabolism
Chemical
Reg. No./Substance:
0/Cell Cycle Proteins; 0/Cyclin-Dependent Kinase Inhibitor p21; 0/RNA, Small Interfering; 0/Tumor Suppressor Protein p53; EC 2.7.7.49/Telomerase

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