ADP-ribosyltransferase activity during the friend virus-induced murine erythroleukemia cell differentiation

A variety of chemical agents that are known to induce erythrodifferentiation in the Friend virus-induced murine erythroleukemia (MEL) cell have been suggested to mediate DNA cleavage in cultured cells prior to differentiation. The activation of the nuclear enzyme, ADP-ribosyltransferase, depends upon the presence of single strand breaks in DNA. If dimethyl sulfoxide (Me2SO) causes DNA breakage, it would be expected that the activity of ADP-ribosyltransferase would increase. A study of ADP-ribosyltransferase activity during cell growth indicates that both Me2SO-treated and untreated MEL cells exhibit a similar increase in the enzyme activity but the increase in Me2SO-treated cells is delayed by a few hours. When examined at comparable stages of growth, both treated and untreated cells show almost identical levels of enzyme activity. The present data thus do not support the contention that Me2SO induces DNA breakage in the MEL cells.