Accession Number:

ADA279430

Title:

Molecular Toxicology of Chromatin

Descriptive Note:

Annual rept. 1 Apr 1993-31 Mar 1994

Corporate Author:

SAN FRANCISCO STATE UNIV TIBURON CA ROMBERG TIBURON CENTERS

Personal Author(s):

Report Date:

1994-04-08

Pagination or Media Count:

74.0

Abstract:

Intracellular phosphorylation of poly ADP-ribose polymerase was assayed in streptolysin-0-permeabilized human lymphocytes. Whereas 32P incorporation from gamma-32PATP into immuno-precipitated enzyme protein was undetectable in resting cells, significant phosphorylation of this enzyme was observed in lymphocytes treated with phytohemagglutinin. The phosphorylation of poly ADP-ribose polymerase in permeabilized cells was not stimulated by phorbol ester, but phosphorylation of other proteins and of a specific oligopeptide substrate of protein kinase C was increased by phorbol ester. The specific inhibitory pseudosubstrate peptide of protein kinase C blocked the phosphorylation of poly ADP-ribose polymerase induced by phytohemagglutinin. A potential role of a member of the protein kinase C family in the intracellular regulation of poly ADP-ribose polymerase by phosphorylation appears probable. The structure of poly ADP-ribose polymerase has been augmented by the identification of polypeptide sequences which define histone and self association. Both protein binding domains are components of 64-67 kDa basic moiety of poly ADP-ribose polymerase, obtained by degradation by chymotrypsin or plasmin. Two discrete his tone binding domains are interspersed and contiguous with selfbinding domains and are located at 186-290 and 446-525 residues. Self binding is confined to the 29 kDa N-terminal moiety of poly ADP-ribose polymerase and to two smaller polypeptide sequences 291-395 and 526-606 residues. Bound zinc is not required for self binding.

Subject Categories:

  • Biochemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE