Open AccessThe telomere length dynamic and methods of its assessment
Author(s) -
Lin KahWai,
Yan Ju
Publication year - 2005
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2005.tb00395.x
Subject(s) - telomere , telomerase , biology , microbiology and biotechnology , telomerase reverse transcriptase , somatic cell , reverse transcriptase , embryonic stem cell , in situ hybridization , stem cell , dna , genetics , rna , messenger rna , gene
Human telomeres are composed of long repeating sequences of TTAGGG, associated with a variety of telomere‐binding proteins. Its function as an end‐protector of chromosomes prevents the chromosome from end‐to‐end fusion, recombination and degradation. Telomerase acts as reverse transcriptase in the elongation of telomeres, which prevent the loss of telomeres due to the end replication problems. However, telomerase activity is detected at low level in somatic cells and high level in embryonic stem cells and tumor cells. It confers immortality to embryonic stem cells and tumor cells. In most tumor cells, telomeres are extremely short and stable. Telomere length is an important indicator of the telomerase activity in tumor cells and it may be used in the prognosis of malignancy. Thus, the assessment of telomeres length is of great experimental and clinical significance. This review describes the role of telomere and telomerase in cancer pathogenesis and the dynamics of the telomeres length in different cell types. The various methods of measurement of telomeres length, i.e . southern blot, hybridization protection assay, fluorescence in situ hybridization, primed in situ , quantitative PCR and single telomere length analysis are discussed. The principle and comparative evaluation of these methods are reviewed. The detection of G‐strand overhang by telomeric‐oligonucleotide ligation assay, primer extension/nick translation assay and electron microscopy are briefly discussed.