Telomeres and Oxidative Stress.

Telomeres are long repetitive DNA sequences of TTAGGG located at the end of the linear chromosomes and bound by shelterin proteins. Shelterin proteins function as the protection for the loop structure of telomere, which prevents the chromosome ends uncapped; resemble a DNA break and activates DNA repair mechanism. Telomere length is maintained by an enzyme called telomerase. There are several factors that can shorten the telomeres which include telomere attrition during cell division, deficiency of Rad 54, which is involved in DNA repair and the methylation of histones H3 and histones H4, which can diminish telomerase activity. Three major mechanisms which influence the telomere length are the end-replication problem, the action of C-strand-specific exonuclease and oxidative DNA damage induced by environmental risk factors. However, oxidative stress has been shown to be the major mechanism which can influence the telomere length. This review explores the association between telomere length a oxidative stress.