Differential activation of a calcium-dependent endonuclease in human B lymphocytes. Role in ionomycin-induced apoptosis.

摘要: The state of B cell maturation profoundly influences the outcome, i.e., activation, growth arrest, or programmed death, a variety stimuli, including calcium ionophore, ionomycin. Initial studies confirmed observation that lines representative immature cells, Burkitt lymphoma lines, were induced to undergo apoptosis in response ionomycin, whereas more mature did not, and instead underwent cycle arrest G1 interval. To understand this differential we have focused on comparing expression activation an endonuclease(s) cells by ionomycin death (Ramos) with resistant ionomycin-induced (Ly1). Our results demonstrated low m.w. fraction endogenous Ca2+/Mg(2+)-dependent endonuclease was activated Ramos but not Ly1 following addition Of interest, however, activity when isolated nuclei treated exogenous instead. Use field inversion gel electrophoresis further indicated cleavage DNA into large (> 50 kbp) fragments does precede internucleosomal ionomycin-resistant cells. In summary, these data support conclusion involves latent, m.w., calcium-responsive suggest control depression may contribute cell-specific regulation ionophore-induced apoptosis.