Sl. Sabol et al., Inhibition of apoptosis-associated DNA fragmentation activity in nonapoptotic cells: The role of DNA fragmentation factor-45 (DFF45/ICAD), BIOC BIOP R, 253(1), 1998, pp. 151-158
Citations number
26
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
We have investigated the mechanism whereby nuclear DNA fragmentation activi
ty emerging during early apoptosis is inhibited during normal cell life. In
a cell free system, cytosol fractions from diverse non-apoptotic human cel
l lines (Jurkat T-cell leukemia, HeLa carcinoma, SK-N-MC neuroblastoma, and
WI-38 embryonic lung fibroblast) potently neutralized the nuclear DNA frag
mentation activity of cytosol from apoptotic anti-Fas treated Jurkat cells.
Recombinant human DNA fragmentation factor 45 kDa subunit (DFF45/ICAD), an
inhibitor of the caspase-activated DNase DFF40/CAD, substituted for health
y cytosol in inhibiting DNA fragmentation, An antiserum against human DFF45
detected 44 and 34 kDa proteins (major and minor, respectively) in the cyt
osols but not in the nuclear or membrane fractions of various cultured huma
n cells. Cytosols depleted of DFF45/ICAD by immunoadsorption had little or
no inhibitor of nuclear DNA fragmentation activity and no caspase-activated
DNA fragmentation activity. We conclude that immunoreactive DFF45/ICAD is
the principal inhibitor of apoptotic DNase activity in the cytosol of healt
hy cells, (C) 1998 Academic Press.