Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 10, 1998
Publication Date: N/A
Technical Abstract: The caspases are an integral part of the protease cascade that results in apoptosis, or programmed cell death, in virus-infected cells. Following the elicitation of the death signal, the caspases are activated sequentially and then proteolytically cleave their substrate molecules in a site-specific manner. Three members of this protease family, caspases 3, 7 and 8, were cloned from a bovine lymph node cDNA library, sequenced and subcloned into the mammalian expression vector, pcDNA3. In transient co-transfection experiments using luciferase as a marker, caspases 7 and 8 were able to efficiently kill transfected cells as determined by a reduction of up to 90% to 95% of luciferase activity when compared to luciferase-only controls. Titration studies showed that the degree of luciferase luminescence reduction was dependent on amount of caspase plasmid transfected. Specific caspase inhibitors prevented the decrease in luciferase activity, indicating inhibition of proteolytic activity. Examination of luciferase activity at various times revealed that cell death is detectable between 10 and 16 hours post-transfection. This work will lead to a better understanding of the role of these proteases in the death processes of virus-infected cells.