PATHOLOGY

Detailed explanation-1: -Whereas cell division gradually shortens telomeres in adult cells, their sequences are continuously extended in early stages of development. By reactivating genes used early in development, embryonic stem cells may be able to elongate exposed telomeres rather than triggering a DNA damage response, the researchers say.

Detailed explanation-2: -With each cell replication, the telomeres get shorter and shorter until they’re so short that your cells can no longer divide. When cells no longer divide, tissues age. However, telomeres can be rebuilt by an enzyme called telomerase to restore cell division.

Detailed explanation-3: -When telomeres become critically short, they activate a DNA damage response that results in cell cycle arrest. To counteract telomere attrition pluripotent stem cells are equipped with telomere elongation mechanisms that ensure prolonged proliferation capacity and self-renewal capacity.

Detailed explanation-4: -In embryonic stem cells, telomerase is activated and maintains telomere length and cellular immortality; however, the level of telomerase activity is low or absent in the majority of stem cells regardless of their proliferative capacity.