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Genome reprogramming during the first cell cycle of embryonic development
Barnetová, Irena ; Fulka, Josef (advisor) ; Pěknicová, Jana (referee) ; Strejček, František (referee)
The sperm head contains highly compacted genome. This compaction is mediated by protamines. Sperm protamines are replaced by cytoplasmic histones after the sperm entry into the oocyte. Beside the proteins replacement, also some epigenetic remodeling occurs. One of the most studied epigenetic remodeling in early zygotes is DNA demethylation. This phenomenon was observed in some mammals (mouse, rat, monkey) but not in some other mammals (sheep) and what is more, in some of them quite inconsistent data were published (pig, human, goat, rabbit). In our work we were mostly concentrated on porcine zygotes and attempted to explain the reasons of inconsistency in observed data. Three factors were evaluated in our work - the technique of embryo production, sperm factors, and the oocyte quality. In the first part of the study (the technique of embryo production) we compared the zygotes produced by conventional in vitro fertilization and zygotes produced by intracytoplasmic sperm injection. The epigenetic remodeling was evaluated by immunolabeling. There were no differences between zygotes produced by the two mentioned techniques. The paternal genome was not demethylated in any of zygotes. The labeling with anti-H3/K9- me2 (anti dimethyl group on lysine 9 of histone 3) showed the positive labeling of both...
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