Poly(ADP-ribosylation) of DNA topoisomerase I: a nuclear response to DNA-strand interruptions

DNA in eukaryotic chromosomes is organized differently from prokaryotic DNA. It seems highly probable that mechanistic adjustments have been made in macromolecular DNA metabolism as a consequence of the chromatin structure of the eukaryotic chromosome (Igo-Kemenes et al. 1982)). This paper deals with an enzyme from eukaryotes, poly(ADP-ribose) synthetase, which may have a role in chromatin metabolism, and, in particular, we focus on the interaction between this enzyme and another enzyme that affects the structure of DNA, type-I DNA topoisomerase.