title: Etoposide interferes with the process of chromatin condensation during alga Chara vulgaris spermiogenesis.
abstract: DNA topoisomerase II plays an essential role in animal spermiogenesis, where changes of chromatin structure are connected with appearance of transient DNA breaks. Such topo II activity can be curtailed by inhibitors such as etoposide and suramine. The aim of the present study was to investigate, for the first time, the effect of etoposide on spermatid chromatin remodeling in the green alga Chara vulgaris. This inhibitor prolonged the early spermiogenesis stages and blocked the formation of the phosphorylated form of histone H2AX at stages VI-VII. The lack of transient DSBs at these stages impairs the elimination of supercoils containing nucleosomes which lead to disturbances in nucleoprotein exchange and the pattern of spermatid chromatin fibrils at stages VI-VIII. Immunofluorescent and ultrastructural observations revealed that during C. vulgaris spermiogenesis topo II played an important role similar to that in mammals. Some corresponding features had been pointed out before, the present studies showed further similarities.
authors.affiliation: Department of Cytophysiology, Faculty of Biology and Environmental Protection, University of Łódź, Pomorska 141/143, 90-236 Łódź, Poland. Electronic address: wojag@biol.uni.lodz.pl.
authors.forename: Wojtczak
authors.initials: W
authors.lastname: Agnieszka
mesh_terms: D002467:Cell Nucleus / Q000187:drug effects / Q000502:physiology; D044784:Chara / Q000187:drug effects* / Q000502:physiology*; D000460:Chlorophyta / Q000187:drug effects* / Q000502:physiology*; D002843:Chromatin / Q000187:drug effects* / Q000502:physiology; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects / Q000502:physiology; D004250:DNA Topoisomerases, Type II / Q000378:metabolism; D005047:Etoposide / Q000494:pharmacology*; D006657:Histones / Q000378:metabolism; D009707:Nucleosomes / Q000187:drug effects / Q000378:metabolism; D013091:Spermatogenesis / Q000187:drug effects* / Q000502:physiology
chemical_list: D002843:Chromatin; D006657:Histones; D009707:Nucleosomes; D005047:Etoposide; D004250:DNA Topoisomerases, Type II
keywords: Chara vulgaris; Chromatin remodeling; Etoposide; H2AX histone; Nuclear protein exchange; Spermiogenesis