Expression of telomerase reverse-transcriptase ( in the rainbow trout (Oncorhynchus mykiss) eggs with varied developmental competence for gynogenesis

Abstract

Abstract Expression of the telomerase reverse-transcriptase (TERT) gene and activity of telomerase have been reported in the somatic tissues and gonads in fish irrespective of their age and size. Nevertheless, little is known about TERT expression in the fish eggs. In the present research, TERT expression was confirmed in the rainbow trout ovulated eggs before and after activation with non-irradiated and UV-irradiated sperm. Eggs originating from eight females had high and comparable quality expressed by similar hatching rates. However, the development of eggs activated with UV-irradiated sperm and further exposed to the High Hydrostatic Pressure (HHP) shock to provide gynogenetic Doubled Haploids (DHs) varied between females from 2.1 ± 0.4% to 40.5 ± 2.2%. Elevated TERT expression was confirmed in gametes originating from two females. However, only eggs from one of these females had increased competence for gynogenesis. In turn, eggs from the female that exhibited the highest survival after gynogenetic activation were characterized by the lowest TERT expression. TERT expression in the fish female gametes is presumably linked with the maintenance of the telomere length and the mechanism of Double Strand Breaks repair however, its upregulation does not assure increased ability of the rainbow trout eggs for the gynogenetic development.