The dynamic nature of DNA-strand breaks present in differentiating muscle cells and quiescent lymphocytes.

Cellular differentiation in a number of eukaryotic systems is associated with changes in the number of DNA-strand breaks and involves the activity of adenosine diphosphoribosyl transferase (ADPRT). DNA-strand breaks are essential for activation of nuclear ADPRT, the activity of which is required for efficient religation of DNA-strand breaks. In this study we demonstrate the dynamic nature of DNA-strand breaks formed in the genome of differentiating avian skeletal muscle cells and quiescent human lymphocytes. Inhibition of ADPRT activity blocks DNA-strand ligation in both cell types and leads to the accumulation of a higher number of strand breaks.