Telomere biology in Metazoa

Abstract 

In this review we present critical overview of some of the available literature on the fundamental biology of telomeres and telomerase in Metazoan. With the exception of Nematodes and Arthropods, the (TTAGGG)_n sequence is conserved in most Metazoa. Available data show that telomerase-based end maintenance is a very ancient mechanism in unicellular and multicellular organisms. In invertebrates, fish, amphibian, and reptiles persistent telomerase activity in somatic tissues might allow the maintenance of the extensive regenerative potentials of these species. Telomerase repression among birds and many mammals suggests that, as humans, they may use replicative aging as a tumor protection mechanism.

Abbreviations: ALT, alternative lengthening of telomeres, bp, base pair(s), chTERT, chicken telomerase reverse transcriptase, DNA, deoxyribonucleic acid, FISH, fluorescence in situ hybridization, fTERT, Fugo telomerase reverse transcriptase (protein component), hTERT, human telomerase reverse transcriptase (protein component), TR/TERC, telomerase RNA (template RNA component), mTR, mouse telomerase RNA (template RNA component), kb, kilobase pair(s), Mb, megabase pair(s), MEFS, mouse embryo fibroblasts, mRNA, messenger RNA, mTERT, mouse telomerase reverse transcriptase (protein component), PD, population doublings, stasis, stress or aberrant signaling induced senescence, TRF, telomere restriction fragment, xTERT, Xenopus telomerase reverse transcriptase (protein component)

Keywords: Telomere, Telomerase, Senescence, Metazoa, Vertebrate, Invertebrate