In humans, telomerase is usally expressed at higher levels in the germline compares to somatic cells,...

In humans, telomerase is usally expressed at higher levels in the germline compares to somatic cells, such as the nueron or skin epithelial cells. WHY?

Expert Solution

Telomeres are guanine-rich tandem DNA repeats found at the end of linear chromosomes which block fraying or sticking of adjacent chromosomes in eukaryotes. They do not contain any genes and normally shorten with every round of replication. Telomerase (also known as Terminal transferase), is an enzyme which adds the repetitive sequences at 3' end of telomeres.

In somatic cells the activity of telomerase is diminished after birth. This is the reason for shortening of telomeres and induction of cellular senescence. In embryonic stem cells, telomerase is expressed in higher levels to maintain the length of telomeres and cellular immortality. Thus, regulation of telomerase plays significant roles in cellular aging and tumorigenesis. Repression of telomerase in somatic cells appears to have evolved as a powerful protective barrier against cancer, which is achieved by transcriptional repression of hTERT, the gene encoding the catalytic subunit of telomerase.

The expression of telomerase is obligatory for continuous tumour cell proliferation, clonal evolution and malignant progression. Telomerase, therefore, has become an attractive target at which new anti-cancer drugs aim.

gladiator answered 1 year ago

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Which cells use telomerase and which cells inhibit it?

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