title: Involvement of caspace-3 in the cleavage of terminal transferase.
abstract: To investigate the in vivo role of caspase-3 in Terminal Transferase metabolism DMSO-treated RPMI-8402, a human pre-T cell line was used. In DMSO treated samples (3)H-dGTP incorporation and TdT phosphorylation occurs after 4 hours of treatment. After 8 hours cells undergo TdT proteolysis in addition to its inactivation. The cleavage of TdT into 32- and 58-KDa proteolytic fragments occurred simultaneously with the activation of Caspase-3, but preceded changes associated with the apoptotic process described after 48 hours of treatment. The Caspase-3 peptide inhibitor V, used as a specific inhibitor, prevented TdT proteolysis prolonging its activity and rescued cells from apoptosis. Our experiments suggest that TdT is a nuclear substrate for Caspase-3, the main apoptotic effector protease in many cell types, and that the cleavage of TdT represents a primary step in a signal cascade leading to pre-T cell apoptosis.
authors.affiliation: Dip. Scienze Odontostomatologiche, Università "G. D'Annunzio", Chieti, Italy.
authors.forename: O.
authors.initials: O
authors.lastname: Trubiani
authors.forename: S.
authors.initials: S
authors.lastname: Guarnieri
authors.forename: R.
authors.initials: R
authors.lastname: Paganelli
authors.forename: R.
authors.initials: R
authors.lastname: Di Primio