Bovine herpesvirus type 1 (BHV-1) up-regulates telomerase activity in MDBK cells.

The proliferative capacity ofmammalian cells is regulated by telomerase, an enzyme uniquely specialised for telomeric DNA synthesis. The critical role of telomerase activation in tumor progression and maintenance has been well established in studies of cancer and of oncogenic transformation in cell culture. Experimental data suggest that telomerase activation has an important role in normal somatic cells, and that failure to activate sufficient telomerase also promotes disease. Evidence regarding the role of telomerase in the pathogenesis of several viruses including human immunodeficiency virus has led to an increased interest in the role of telomerase activity in other virus infections. In this research we evaluated the telomerase modulating activity of Bovine herpesvirus 1 (BHV-1) in MDBK cells. MDBK cells were infected at differentmultiplicity of infection with BHV-1 Cooper strain and telomerase activity at different times post- infection was measured by the TRAP assay. Our data indicate that BHV-1 significantly up-regulates telomerase activity at 3 and 6 h post-infection decreasing after the 24 h post-infection. Our data, showed that the effect was mediated by an immediate-early or early viral gene, and use of the protein translation inhibitor cycloheximide confirmed that an immediate early gene is primarily responsible.