Induction of Telomerase Catalytic Subunit Alternative Splicing by Apoptotic Endonuclease G in Mouse and Rat Lymphocytes

It is known that apoptotic endonuclease G (EndoG) induces alternative splicing (AS) of telomerase catalytic subunit TERT (telomerase reverse transcriptase) mRNA and inhibits telomerase activity in tumor cells and activated human T cells. The aim of this study was to investigate the possibility of TERT mRNA AS induction and inhibition of telomerase activity by EndoG in activated mouse and rat lymphocytes. To induce EndoG expression, mouse and rat CD4+, CD8+ T cells, B cells, and NK cells were transfected with the pEndoG-GFP plasmid or incubated with the DNA-damaging agent cisplatin in vitro. The increase in the EndoG expression resulted in decreased expression of full-length active TERT variant, enhanced synthesis of the truncated splicing variant, and decreased telomerase activity. An increase in the EndoG expression, a change in the mRNA pool of TERT splicing variants, and inhibition of telomerase activity were observed in mouse and rat lymphocytes after cisplatin administration in vivo. Thus, EndoG is capable of inducing TERT mRNA AS and regulating telomerase activity in mouse and rat lymphocytes.