Induction of foci of phosphorylated H2AX histones and premature chromosome condensation after DNA damage in <Emphasis Type="Italic">Vicia faba</Emphasis> root meristem |
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Authors: | D Rybaczek J Maszewski |
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Institution: | (1) Department of Cytophysiology, University of Łódź, ul. Pilarskiego 14, PL-90231 Łódź, Poland |
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Abstract: | Immunocytochemical analysis using antibody raised against human H2AX histones phosphorylated at serine 139 (γ-H2AX) demonstrates
that root meristem cells of Vicia faba exposed to UV-radiation or incubated with hydroxyurea (HU) reveal discrete foci at the border of the nucleolus and perinucleolar
chromatin or scattered over the whole area of cell nucleus. Western blots detected only one protein band at the position expected
for the phosphorylated form of H2AX. The dose-effect relationship was demonstrated following treatment with 2.5 and 10 mM
HU. Proteins extracted from root meristems incubated for 2 h either with HU and caffeine or with HU and sodium metavanadate
showed unchanged amounts of bound γ-H2AX antibodies, as compared to root meristems treated with 2.5 mM HU. Higher quantities
of phosphorylated H2AX histones were detected in proteins extracted from roots treated with HU and 2-aminopurine. All treatments
were effective in producing evident aberrations of premature mitosis: broken and lagging chromatids, acentric fragments, chromosomal
bridges and micronuclei. Our results show that phosphorylation of H2AX at the carboxy-terminal Ser-Gln-Glu sequence is among
the earliest responses to double-strand breaks and, presumably, one of the key ATM/ATR-dependent signals indispensable for
the repair of spontaneous and induced DNA damage in plant cells. |
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Keywords: | field bean hydroxyurea premature mitosis UV-radiation |
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