This protein is present at telomeres throughout the cell cycle and functions as an inhibitor of telomerase, acting in cis to limit the elongation of individual chromosome ends.

It is known to protect telomeres in mammals from DNA mechanisms that are used for repair purposes and at the same time regulate the activity carried out by telomerase.

[7] The progressive loss of the telomeric ends of chromosomes is an important mechanism in the timing of human cellular aging.

The protein acts as cis-regulatory elements in the process of limiting the ends of individual chromosomes from elongating as facilitated by telomerase and the TTAGGG sequences.

The protein encoded by the TERF 1 gene is also involved in the biological process of cell division and the negative regulation of the maintenance of telomere facilitated by the enzyme telomerase.

The progressive loss of the telomeric ends of chromosomes is an important mechanism in the timing of human cellular aging.

To measure the concentrations of TRF1 and the relationships among telomere length, telomerase activity, and TRF1 levels in tumor and normal colorectal mucosa, from normal and tumoral samples of patients who underwent surgery for colorectal cancer we analyzed TRF1 protein concentration, and telomerase activity were analysed.