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Topic: Telomere


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In the News (Wed 21 Aug 19)

  
  Telomere - Wikipedia, the free encyclopedia
A telomere is a region of highly repetitive DNA at the end of a chromosome that functions as a disposable buffer.
Telomeres are extended by telomerases, specialized reverse transcriptase enzymes that are involved in synthesis of telomeres in humans and many other, but not all, organisms.
Telomeres shorten because of the lagging strand phenomenon that is exhibited during DNA replication in eukaryotes only.
en.wikipedia.org /wiki/Telomere   (1260 words)

  
 Science--de Lange, et al.
Knowing that telomeres were threatened by loss in each cell division unless their repeated sequences were replenished by telomerase, Cooke speculated that this enzyme [then just discovered in a ciliated protozoan (2)] might not be active in normal somatic human cells.
Telomere-clock champions were also fortified by the consistent shortening of telomeres during cellular aging in culture and with aging of human tissues in vivo (5, 6).
Since the telomere barrier to proliferation does not manifest itself until many cell divisions have passed, this mechanism may not be useful for a small animal in which a 2-cm mass of misplaced cells could be life-threatening.
www.sciencemag.org /feature/data/telomerase/delange.dtl   (1525 words)

  
 Le Magazine, October 2002 - Report: Telomere Control & Cellular Aging
TPE is dependent on telomere length and the position of the gene in relation to the telomere.
These experiments showed that the proximity of a telomere to a gene silences the gene: when the telomere is lengthened, and the gene is located further away from the critical end of the telomere, it is silenced even more.
As the cell divides and the telomere shortens, an "aging gene" would be more affected by its position on the telomere, as it increases its proximity to the end of the telomere.
www.lef.org /magazine/mag2002/oct2002_report_telo_01.html   (2201 words)

  
 Le Magazine February 1998
They showed that telomere length correlated with cellular senescence whether you were looking at cells you had cultured in the lab or you were looking at cells you had drawn from different age individuals.
If telomere shortening times the onset and progression of cellular aging, then if you could reset the telomere length, you should be able to show that the cells have a longer replicative life span.
The mean telomere length in the fibroblasts of a 5-year-old progeric child is about the same as the mean length you would expect to find in the fibroblasts of an 80- or 90-year-old.
www.lef.org /magazine/mag98/feb98_interview.html   (3281 words)

  
 Telomere.net
Telomeres are sequences at the ends of chromosomes.
Thus, telomere erosion and Hayflick limits could account for most of the decline in efficiency, and increases in vulnerability that characterizes the aging of sexually mature mammals.
The system of finite, eroding telomeres provides us that ability to repair and maintain our tissues for a substantial period, during which time the runaway cells that would otherwise become deadly tumors are rained in by the Hayflick failsafe.
www.telomere.net   (1506 words)

  
 Department of Human Genetics - Telomere Analysis   (Site not responding. Last check: 2007-11-06)
Current methods for exacting telomere analysis are problematic, such as G-banding due to the terminal G-negative regions and the use of whole chromosome painting probes, which lack sufficient sensitivity to identify small terminal rearrangements or deletions.
Examples of FISH images using these probes and diagrams showing telomeric structures and the localization of the unique telomere probes can be viewed in our Telomere Atlas.
Cryptic telomeric rearrangements have been identified in cases of mental retardation and multiple congenital anomalies of previous unknown etiology and have been estimated to account for 5-10% of idiopathic mental retardation.
www.genes.uchicago.edu /ucgs/special-diagnostics/TA/telall.html   (354 words)

  
 ScienceWeek
Since that time we have discovered that the telomere is a complex structure composed of both DNA and a growing list of associated proteins that together serve to regulate the length of the telomere and, as predicted by McClintock, protect genomic integrity.
The ability of telomerase to rescue cells from the adverse consequences of telomere dysfunction is likely critical for its role in facilitating malignant transformation of primary human cells and in maintaining the viability of established cancer cells.
In contrast to humans, the laboratory mouse possesses long telomeres and, even in early generation telomerase-deficient mice, the level of telomere reserve is sufficient to avert telomere-based checkpoint responses and to permit full malignant progression.
scienceweek.com /2003/sc031226-4.htm   (1161 words)

  
 CD Baby: TELOMERE: Zoetosis
On this recording, Telomere established himself as one of spacemusic's foremost deep-drift stylists.
With barely a rhythm or melody, Telomere produces engaging harmonies and evolving timbres to convey profound musical ideas.
Telomere's music ascends with a clarity of vision found only far above the earth's atmosphere.
www.cdbaby.com /cd/telomere2   (280 words)

  
 BBC NEWS | Health | Smoking and obesity 'age people'
Telomeres shorten each time a cell divides, until there is nothing left, making cell division less reliable and increasing the risk of disorders.
By analysing blood samples for DNA the researchers found telomere length decreased steadily with age, as expected.
However, the telomeres of the obese women and smokers were far shorter than those of lean women and those who had never smoked of the same age.
news.bbc.co.uk /2/hi/health/4086900.stm   (615 words)

  
 What are Telomeres?   (Site not responding. Last check: 2007-11-06)
Telomeres are the physical ends of linear eukaryotic chromosomes.
Often sequences adjacent to the telomeric repeats are highly polymorphic, are rich in DNA repetitive elements (termed subtelomeric repeats), and in some cases, genes have been found in the proterminal regions of chromosomes.
Eventually telomeric sequences can shorten to the point where they are not long enough to support the telomere-protein complex protecting the ends and the chromosomes become unstable.
www.genlink.wustl.edu /teldb/tel.html   (337 words)

  
 Telomeres   (Site not responding. Last check: 2007-11-06)
Telomeres are specialized structures that are essential for protecting chromosome ends and ensuring chromosome stability
Telomeres are 4-6 kb [5-7 kb] in length (average)
The telomere hypothesis of aging hinges on the cellular/replicative senescence hypothesis of aging
mcb.berkeley.edu /courses/mcb135k/telomeres.html   (333 words)

  
 Telomerase Activity Is Increased and Telomere Length Shortened in T Cells from Blood of Patients with Atopic Dermatitis ...
Telomerase Activity Is Increased and Telomere Length Shortened in T Cells from Blood of Patients with Atopic Dermatitis and Psoriasis -- Wu et al.
Comparison of mean telomere length on different T cell subsets from normal individuals (a) and from patients with psoriasis (b) and AD (c).
T cell clonal expansion is associated with telomerase up-regulation and telomere length preservation: a mechanism for rescue from replicative senescence.
www.jimmunol.org /cgi/content/full/165/8/4742   (3741 words)

  
 Hepatocyte telomere shortening and senescence are general markers of human liver cirrhosis -- WIEMANN et al. 16 (9): ...
a consequence of hepatocyte telomere shortening and senescence.
The quantification of the telomere fluorescence intensity was
The telomere fluorescence intensity of stellate cells (SC) and lymphocytes (LC) was analyzed in cirrhosis.
www.fasebj.org /cgi/content/full/16/9/935   (4848 words)

  
 Telomere synthesis   (Site not responding. Last check: 2007-11-06)
The structure that is the telomere is made by reverse transcription.
The telomere DNA polymerase is a reverse transcriptase (RNA-dependent).
Progressive shortening of telomeres may be a mechanism of aging and can lead to tumor formation, particularly when DNA repair processes are impaired (ref).
opbs.okstate.edu /~melcher/MG/MGW1/MG1353.html   (330 words)

  
 Telomere Cancer Theory   (Site not responding. Last check: 2007-11-06)
Equally important, I described how the telomere subunit is involved in the initiation of cancer.
In the paper I show that cancer is initiated by the mutation of the telomere subunit sequence.
A mutated telomere subunit is the loose cannon in the cell.
hood.hctc.com /~darby   (412 words)

  
 Plant Telomere Biology -- McKnight and Shippen 16 (4): 794 -- THE PLANT CELL
Blackburn, E.H., and Gall, J.G. A tandemly repeated sequence at the termini of the extrachromosomal ribosomal RNA genes in Tetrahymena.
Greider, C.W., and Blackburn, E.H. A telomeric sequence in the RNA of Tetrahymena telomerase required for telomere repeat synthesis.
Yu, G.L., Bradley, J.D., Attardi, L.D., and Blackburn, E.H. In vivo alteration of telomere sequences and senescence caused by mutated Tetrahymena telomerase RNAs.
www.plantcell.org /cgi/content/full/16/4/794   (5951 words)

  
 Telomere attrition and Chk2 activation in human heart failure -- Oh et al. 100 (9): 5378 -- Proceedings of the National ...
Telomere maintenance is one mechanism through which cell viability is preserved (13-21).
Telomere length (A), TRF2 levels (B), and Chk2 kinase activation (C) were measured as in Fig.
(3), telomere length was 21.5 ± 0.5 kbp in the
www.pnas.org /cgi/content/full/100/9/5378   (3267 words)

  
 From the Cover: Accelerated telomere shortening in response to life stress -- Epel et al. 101 (49): 17312 -- ...
Scatter plots of chronicity of stress by telomere length in caregivers and perceived stress scores by telomere length.
To test whether the age of the child accounts for this relationship independently of caregiving, correlations between the age of the child and the mean telomere length were calculated in each group.
These findings demonstrate that the relationship between chronicity of caregiving and mean telomere length is not simply due to either the mother's or child's older age.
www.pnas.org /cgi/content/full/101/49/17312   (2993 words)

  
 Differences in telomere length between homologous chromosomes in humans -- Londoño-Vallejo et al. 29 (15): 3164 ...
The circles represent mean relative fluorescence intensities measured on telomeres for both homologs of chromosomes 7p and 11p from the same donor.
The circles indicate the mean relative intensities obtained for each telomere on both homologs of chromosomes 8 and 9, at different population doublings.
29 Reveal,P.M., Henkels,K.M. and Turchi,J.J. (1997) Synthesis of the mammalian telomere lagging strand in vitro.
nar.oxfordjournals.org /cgi/content/full/29/15/3164   (4384 words)

  
 Telomere Length in the Newborn -- OKUDA et al. 52 (3): 377 -- Pediatric Research   (Site not responding. Last check: 2007-11-06)
Telomere Length in the Newborn -- OKUDA et al.
Telomere length was measured by the mean length of the terminal
Morin GB 1989 The human telomere terminal transferase enzyme is a ribonucleoprotein that synthesizes TTAGGG repeats.
www.pedresearch.org /cgi/content/full/52/3/377   (2686 words)

  
 Telomere Shortening Is Nearly Universal in Pancreatic Intraepithelial Neoplasia -- van Heek et al. 161 (5): 1541 -- ...
Telomere Shortening Is Nearly Universal in Pancreatic Intraepithelial Neoplasia -- van Heek et al.
Telomere Shortening Is Nearly Universal in Pancreatic Intraepithelial Neoplasia
Telomere Shortening and Telomerase Reverse Transcriptase Expression in Preinvasive Bronchial Lesions
ajp.amjpathol.org /cgi/content/abstract/161/5/1541   (1125 words)

  
 Telomere Position Effect in Human Cells -- Baur et al. 292 (5524): 2075 -- Science
Telomere Position Effect and Silencing of Transgenes near Telomeres in the Mouse.
Telomere epigenetics: a higher-order control of telomere length in mammalian cells.
Telomere length and the expression of natural telomeric genes in human fibroblasts.
www.sciencemag.org /cgi/content/abstract/292/5524/2075   (840 words)

  
 Smurf2 up-regulation activates telomere-dependent senescence -- Zhang and Cohen 18 (24): 3028 -- Genes and Development
phenotype in the absence of telomere shortening (Smogorzewska
Stewart, S.A., Ben-Porath, I., Carey, V.J., O'Connor, B.F., Hahn, W.C., and Weinberg, R.A. Erosion of the telomeric single-strand overhang at replicative senescence.
Wright, W.E. and Shay, J.W. Telomere positional effects and the regulation of cellular senescence.
www.genesdev.org /cgi/content/full/18/24/3028   (6324 words)

  
 Assessment of telomere length and factors that contribute to its stability -- Saldanha et al. 270 (3): 389 -- FEBS ...   (Site not responding. Last check: 2007-11-06)
The telomeres of transformed cells are short and in most cases are nearly equal to or less than the length at the M2 threshold stage [100].
Huffman, K.E., Levene, S.D., Tesmer, V.M., Shay, J.W. and Wright, W.E. (2000) Telomere shortening is proportional to the size of the G-rich telomeric-3'-overhang.
Ray, A. and Runge, K.W. (1999) The yeast telomere length counting machinery is sensitive to sequences at the telomere-nontelomere junction.
content.febsjournal.org /cgi/content/full/270/3/389   (6881 words)

  
 Telomere Length in Subpopulations of Human Hematopoietic Cells -- Van Ziffle et al. 21 (6): 654 -- Stem Cells
Telomere Length in Subpopulations of Human Hematopoietic Cells -- Van Ziffle et al.
Telomere Length in Subpopulations of Human Hematopoietic Cells
that the telomere length in subpopulations of hematopoietic
stemcells.alphamedpress.org /cgi/content/abstract/21/6/654   (300 words)

  
 Massive Telomere Loss Is an Early Event of DNA Damage-induced Apoptosis -- Ramírez et al. 278 (2): 836 -- ...
Massive Telomere Loss Is an Early Event of DNA Damage-induced Apoptosis -- Ramírez et al.
Chromosomal stability and cell viability require a proficient telomeric end-capping function.
Effects of arsenic on telomerase and telomeres in relation to cell proliferation and apoptosis in human keratinocytes and leukemia cells in vitro
www.jbc.org /cgi/content/abstract/278/2/836   (666 words)

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