Stem Cell Telomeres
Telomeres are guanine-rich tandem DNA repeats that cap the ends of eukaryotic chromosomes. Their primary function is to prevent chromosomal degradation, fusions, and instability. During cell division, telomeres shorten as a result of the incomplete replication of linear chromosomes. The slow rate of cell turnover in stem cell compartments means a longer period of telomere length stability in stem cells versus somatic cells. Nevertheless, stem cell telomeres do gradually shorten with age.
Human telomeres consist of tandem repetitive arrays of the hexameric sequence TTAGGG, with overall telomere sizes ranging from ∼15 kb at birth down to <5 kb in senescence cells or in some chronic disease states. The end of telomere forms a 3′ overhang of the G-rich strand, which is generated by the postreplicative processing of the C-rich strand and folds back into the duplex...