the presence of dna topoisomerase ii activity in late spermatids and , in addition , the relative increment of drug-induced topo-ii-mediated dna cleavage detected in these cells , suggest that dna topoisomerase ii might modulate the topology of dna during the marked changes that chromatin structure undergoes in the nucleohistone-nucleoprotamine transition at the end of the spermiogenesis and could be involved in the final organization of dna within the nucleus of the male gamete .
C0007634
cells
C0007610
nucleus