title: Endonuclease G interacts with histone H2B and DNA topoisomerase II alpha during apoptosis.
abstract: Apoptosis is a natural form of cell death involved in many physiological changes in the cell. Defects in the process of apoptosis can lead to serious diseases. During some apoptotic pathways, proteins apoptosis-inducing factor (AIF) and endonuclease G (EndoG) are released from the mitochondria and they translocate into the cell nuclei, where they probably participate in chromatin degradation together with other nuclear proteins. Exact mechanism of EndoG activity in cell nucleus is still unknown. Some interacting partners like flap endonuclease 1, DNase I, and exonuclease III were already suggested, but also other interacting partners were proposed. We conducted a living-cell confocal fluorescence microscopy followed by an image analysis of fluorescence resonance energy transfer to analyze the possibility of protein interactions of EndoG with histone H2B and human DNA topoisomerase II alpha (TOPO2a). Our results show that EndoG interacts with both these proteins during apoptotic cell death. Therefore, we can conclude that EndoG and TOPO2a may actively participate in apoptotic chromatin degradation. The possible existence of a degradation complex consisting of EndoG and TOPO2a and possibly other proteins like AIF and cyclophilin A have yet to be investigated.
authors.affiliation: Centre for Biomedical Image Analysis, Faculty of Informatics, Masaryk University, Botanická 68a, 602 00 Brno, Czech Republic. mvara@fi.muni.cz
authors.forename: Miroslav
authors.initials: M
authors.lastname: Vařecha
authors.forename: Michaela
authors.initials: M
authors.lastname: Potěšilová
authors.forename: Pavel
authors.initials: P
authors.lastname: Matula
authors.forename: Michal
authors.initials: M
authors.lastname: Kozubek
mesh_terms: D000951:Antigens, Neoplasm / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017209:Apoptosis; D002467:Cell Nucleus / Q000201:enzymology* / Q000473:pathology; D042002:Chromatin Assembly and Disassembly; D004250:DNA Topoisomerases, Type II / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D031541:Fluorescence Resonance Energy Transfer; D006367:HeLa Cells; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018613:Microscopy, Confocal; D008958:Models, Molecular; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
chemical_list: D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D006657:Histones; D011993:Recombinant Fusion Proteins; D004706:Endodeoxyribonucleases; C052391:endonuclease G; D004250:DNA Topoisomerases, Type II