Telomeres and telomerase activity in pig tissues

Abstract

The current state of the art concerning telomeres and telomerase sterns almost exclusively from the analysis of protozoa, yeast, and a small number of mammals. In the present study, we confirm that the pig telomeric sequence is indeed T(2)AG(3), as previously Suggested. By making use of sequence analysis of pig telorneric DNA variant telorneric repeats in the medial region of the telorneres, interspersed with canonical T(2)AG(3) repeats, were identified. This telomere organization is similar to the one present in humans. Analysis of terminal restriction fragments showed that the majority of telomeres from different pig tissues are longer than ill humans but shorter than in Mus musculus. Telomeres from spermatozoa were found to be longer, ranging in size between 13 and 44 kb. Most of the somatic pig tissues expressed significant levels of telomerase activity, a situation more similar to mouse and that contrasts with the one in humans and dog. Moreover, the analysis of sperm cells from different epididymal compartments of an adult animal showed that telomerase activity is absent in Maturing spematozoa, Suggesting that sperm telomere elongation is restricted during spermatogenesis. (C) 2003 Published by Elsevier SAS