J. Biol. Chem., Vol. 262, Issue 31, 14863-14866, 11, 1987
Endogenous polymers of ADP-ribose are associated with the nuclear matrix
ME Cardenas-Corona, EL Jacobson and MK Jacobson
Department of Biochemistry, Texas College of Osteopathic Medicine, North Texas State University, Forth Worth 76107.
The metabolism of nuclear polymers of ADP-ribose has been implicated in
several chromatin-associated processes. However, the distribution of
endogenous ADP-ribose polymers in the nucleus or within different fractions
of chromatin has not been studied. Using a procedure which allowed the
radiolabeling and detection of endogenous polymers of ADP- ribose, we have
analyzed the nuclear distribution of these polymers in untreated cells and
in cells subjected to hyperthermia, N-methyl-N'- nitro-N-nitrosoguanidine,
or both. When isolated nuclei from cells subjected to any of these
conditions were digested with micrococcal nuclease such that 80% of the DNA
was released, 90% of the total poly(ADP-ribose) remained with the
micrococcal nuclease resistant chromatin fraction. When nuclear matrix
fractions were prepared by exhaustive DNase I digestion in combination with
three different salt extraction procedures (2 M NaCl, 300 mM (NH4)2SO4 or
25 mM lithium diiodosalicylate), the matrices contained less than 1% of the
total nuclear DNA but 50 to 70% of the total poly(ADP-ribose). These data
suggest that the nuclear matrix may be a major site of poly(ADP-ribose)
metabolism.
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