Abstracts (poster) - Wissenschaft Online

Mark Wossidlo
γH2AX in the mouse zygote – implications of DNA repair in
epigenetic reprogramming
Wossidlo M, Lepikhov K, Paelmke N, Walter J
University of Saarland, Natural Sciences – Technical Faculty III, FR 8.3, Biological
Sciences, Genetics/Epigenetics, Saarbrücken, Germany
In mammals shortly after the fertilization of the oocyte the paternal genome undergoes
dramatic epigenetic changes. The paternal DNA in mouse zygotes is rapidly
demethylated by an apparently active mechanism, while the maternal DNA stays
methylated. It still remains unknown which enzymes are responsible for the paternal
DNA demethylation, same holds true for the mechanisms behind the process. Therefore
we examined whether this paternal demethylation is mediated by a ubiquitous DNA
repair process. To address this question we used the indirect immunofluorescense
approach to detect the presence of DNA repair associated phosphorylated histone H2AX
(γH2AX) in mouse zygotes at different pronuclear stages.
We found out that the common DNA strand break associated marker γH2AX
preferentially appears in the paternal pronucleus at certain pronuclear stages. In present
work we describe the dynamic changes of γH2AX pattern, which is influenced by DNA
polymerase inhibitor aphidicolin and at certain pronuclear stages independent on
replication. This replication independent preferential localization of γH2AX in the paternal
pronucleus in early zygotic stages indicates that active DNA demethylation in zygotes
might be linked to DNA repair.
contact:
Mark Wossidlo
Universität des Saarlandes
Genetik / Epigenetik
m.wossidlo@mx.uni-saarland.de
Universitäts Campus Geb. A2.4
66123 Saarbrücken (Germany)