γ-Irradiated DNA Activates Histone Hl-specific Proteinase of Rat Liver Nuclei

Abstract

We investigated the effect of various forms of DNA (double- and single-stranded calf thymus DNA, circular plasmid DNA, gamma- and UV-irradiated DNA and DNAase I-treated double-stranded DNA) aggregated with histones, on the proteolysis of these histones by proteinase associated with the rat liver nuclear scaffold. It was shown that the nuclear scaffold-associated proteinase is able to degrade selectively the histone H1 only in the presence of the DNA containing single-strand breaks induced by gamma-radiation or DNAase I treatment as well as in the presence of heat-denatured DNA. This proteinase is not activated by the double-stranded circular plasmid DNA or by UV-treated double-stranded DNA. Histone H1-specific proteinase (HSP) activated by gamma-irradiated DNA is inhibited by inhibitors of serine proteinases such as antipain, leupeptin, phenylmethylsulphonyl fluoride, as well as by dithiothreitol. The results lead us to suggest that DNA-activated HSP from rat liver nuclei is involved in the regulation of the access of repair enzymes to the damage portions of DNA within chromatin.

Influence of Protein Nutrition on Proteolytic Activity and Histone Content in Isolated Mouse Liver Nuclei

“…There are evidences about the occurrence of changes in nucleosome structure associated with the regulation of transcription (Wolffe 1992;Zweidler 1992;Garcia-Ramirez, Dong and Ausio 1992;Lee, Hayes, Pruss and Wolffe 1993). On the other hand, results of Tsurugi and Ogata (1986) and Gaziev and Kutsyi (1992) suggest that H1 degradation is stimulated by damaged DNA. These facts could be associated with changes in histone contents.…”

Protease inhibitors block apoptosis at intermediate stages: a compared analysis of DNA fragmentation and apoptotic nuclear morphology

“…The Interleukin converting enzyme (ICE protease [1]), as well as proteases present in cytotoxic granules [2,3], when introduced and/or activated in the cell, are able to induce apoptosis; complementary, apoptosis may be blocked by specific protease inhibitors [4]. While most proteins maintain their integrity in the apoptotic cells, several specific proteins have been shown to be proteolitically digested in apoptosis, such as nuclear lamins [5][6][7], fodrin [8], histone H1 [9], poly(ADP-ribose)polymerase [5,10]. Some of the proteases involved in apoptosis have been identified, such as calpain, a Ca2+-dependent cystein protease involved in cytoskeletal alterations (i.e.…”