Expression of telomerase activity and telomeric catalytic subunit in goldfish (Carassius auratus) retina

Abstract

Telomerase is an enzyme stabilizes eukaryotic chromosomes byadding telomeric repeats (TTAGGG) to chromosomal ends. Theenzymatic activity is commonly found in proliferating cells andorgans with regenerating potential, but not postmitotic cells. Unlikemammals, the retina of goldfish grows continuously throughneurogenesis. The aim of this study is to determine whethertelomerase catalytic subunit (TERT) and telomerase activity can bedetected in goldfish (Carassius auratus) retina. Eyes of adultgoldfish were dissected, enucleated and fixed for immunohisto-chemistry while retinas were dissected for telomeric repeat ampli-fication protocol (TRAP) assay. TRAP assay showed thattelomerase activity can be found in goldfish retina. Immunoreac-tivity of TERT was shown strongly in inner nuclear layer and outernuclear layer. The results show that telomerase is present in goldfishretina. As telomerase is correlated with prevention of apoptosis andcell cycle progression in cells, it is possible that telomerase isinvolved in continuous generation of neural retina in goldfish.Unlike mammals, there are groups of neural progenitor cells in innernuclear layer of goldfish retina. These stem cells are the source ofneurons added during growth and after injury. They may be thesource of telomerase activity in goldfish retina. Further studies,which confirm the correlation between telomerase and teleost retinaneurogenesis, are required to understand the role of telomerase inteleost retina development.