Question

Describe in detail how cells can become immortalized without telomerase reactivation. Provide the mechanism for this process.

Answer 1

In eukaryotes, the ends of the eukaryotic chromosomes are called telomeres, whose structure is such that it extends beyond the 5' end as single stranded DNA , which acts as the site of origin of replication and continues to replicate or immortalize the cell by an enzyme called telomerase. Telomerase is also a kind of DNA polymerase . Telomerase reactivation regenerates telomeres, reduces DNA damage signaling and eliminates degenerative phenotypes by restoring telomere integrity. The mechanism is as follows:


​Fig: The telomerase enzyme uses its RNA component to anneal to the 3' end of the single stranded DNA of the telomere. Telomerase then synthesizes DNA by reverse transcription to the end of the RNA template. It then displaces RNA from the newly synthesized DNA and repeats the process rebinding at the end of the telomere.

​Thus, the telomerase reactivation

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