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N Anzai, H Kawabata, T Hirama, H Masutani, Y Ueda, Y Yoshida and M Okuma
Department of Medicine, Faculty of Medicine, Kyoto University, Japan.
A hallmark of apoptosis is internucleosomal DNA fragmentation resulting
from the activation of endonucleases. We characterized the endonuclease
activity of human myeloid cell nuclei that cleaved their own nuclear
chromatin to oligonucleosomal length fragments. Polymorphonuclear
leukocytes (PMNs) of normal peripheral blood contained both Ca2+/Mg(2+)-
dependent and DNase II-like acidic endonuclease activities in their nuclei.
Immature myeloid cells of normal bone marrow at various stages of
granulocytic maturation had similar nuclease activities. In contrast, a
clear difference was shown in the circulating CD34+ cells, in that only
Mg(2+)-dependent, Ca(2+)-independent endonuclease activity was detected.
Consistent with these findings is the emergence of the
Ca2+/Mg(2+)-dependent and acidic endonuclease concomitantly with the
disappearance of the Mg(2+)-dependent endonuclease when CD34+ cells were
induced to differentiate in vitro toward granulocytes. Leukemic cell lines
of all lineages also had Mg(2+)-dependent nuclease activity. Our results
suggest an association of the Mg(2+)-dependent endonuclease with
hematopoietic progenitor cells and that the relative activities of the
nuclear nuclease in human myeloid cells change substantially during
granulocytic differentiation.
This article has been cited by other articles:
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| Copyright © 1995 by American Society of Hematology Online ISSN: 1528-0020 | |||||||||
