[Role of a disorder in poly(ADP-ribosylation) in the activation of Ca/Mg-dependent endonuclease].

The nuclei from the control and irradiated (3 h after irradiation at a dose of 10 Gy) thymocytes were preincubated with NAD in conditions optimal for poly (ADP) ribosylation. This was shown to decrease by 6-7- and 2-3 times, respectively, the rate of autolytic cleavage of DNA by Ca/Mg-dependent endonuclease. The inhibitors of poly (ADP-riboso)-polymerase, nicotine amide and thymidine, removed the effect of NAD. The data obtained prompt an assumption that the post-irradiation activation of Ca/Mg-nuclease in thymocytes is associated with the disturbance of its post-translation modification, poly(ADP)ribosylation.