Detection of Telomerase hTERT Gene Expression and Its Splice Variants by RT-PCR

The finite growth potential of normal cells is termed “cellular senescence” and its regulation appears to involve specialized DNA structures known as telomeres that exist at the ends of all eukaryotic chromosomes (1 ). Human telomeres consist of tandem nucleotide repeats of 6 bp, TTAGGG. They act as protective caps, stabilizing the chromosomes and preventing their degradation and aberrant recombination during cell division. However, they also have the potential to act as a molecular counting mechanism, marking the number of cell divisions. As chromosomes are replicated during cell division, approx 50 bp of telomeric material are lost because of incomplete replication of the lagging strand, termed “the end-replication problem.” In the telomeric clock model, after a certain number of cell divisions, the telomere becomes truncated to a critical level, generating a signal that results in cessation of cell division and senescence (1 –3 ).