Expression of telomerase activity and telomeric catalytic subunit in adult rat retina

Abstract

Telomerase is an enzyme stabilizes eukaryotic linear chromosomes by adding telomeric repeats (TTAGGG) to chromosomal ends. It is believed that such enzymatic activity can only be found in proliferating cells and organs with regenerating potential, but not in post-mitotic cells. The aim of this study is to determine whether telomerase activity and telomerase catalytic subunit (TERT) can be detected in adult rat retina, which consists of differentiated, post-mitotic neurons. Eyes of adult rat were dissected, enucleated and fixed for immunohistochemistry. Retinas were dissected and frozen for telomeric repeat amplification protocol (TRAP) assay, western blotting and reverse-transcription polymerase chain reaction (RT-PCR). TRAP assay showed that telomerase activity can be found in adult rat neural retina. Immunoreactivity of TERT was shown strongly in inner nuclear layer and outer nuclear layer. The presence of TERT was detected by RT-PCR and Western blot. The results show that both telomerase activity and TERT are present in adult rat retina. As telomerase is correlated with prevention of apoptosis and cell cycle progression in cells, it is possible that telomerase is involved in maintaining neuronal survival of rat retina. Further studies are required to elucidate the function of telomerase in adult rat retina and to understand the role of telomerase in rat retinal development. Acknowledgement: This project is supported by a grant from the University of Hong Kong.