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Suppression of nuclear ADP‐ribosyltransferase activity in Ehrlich ascites tumor cells by 5‐azacytidine
Author(s) -
Hoshino Jiro,
Nothacker Hans-Peter,
Schalge Sigrid,
Kröger Hans
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80154-b
Subject(s) - ehrlich ascites , histone , enzyme , in vitro , microbiology and biotechnology , dna , biology , biochemistry , dna synthesis , chemistry , tumor cells , cancer research
Exposure of Ehrlich ascites tumor cells to 5‐azacytidine for 5 h resulted in a partial loss of ability of DNA to stimulate ADP‐ribosyltransferase activity, as assessed in a reconstituted in vitro enzyme system consisting of purified calf thymus enzyme, calf thymus whole histone and DNA isolated from the cells. The degree of suppression in vitro varied depending on the amount of histone and DNA added and it reached a maximum with a value of 83% and 62% of control for DNAs from cells exposed to 10 μM and 30 μM 5‐azacytidine, respectively, at a histone/DNA mass ratio of 0.4. In the absence of histone (conditions of auto‐ADP‐ribosylation of the enzyme), no suppression was detectable.