title: DNA methylation pattern in human zygotes and developing embryos.
abstract: We report on observations of the global methylation/demethylation pattern of both pronuclei in human zygotes and in early embryos up to the blastocyst stage. Our results demonstrate that in about half of the zygotes examined the paternal chromatin was less methylated than the maternal chromatin. In the other half, both pronuclei exhibited the same intensity of labeling. The nuclei in developing embryos were intensively labeled for up to the four-cell stage; thereafter, a decline of labeling intensity was detected. Remethylation in some nuclei starts in late morulae. Surprisingly, and unlike the mouse, at the blastocyst stage the inner cell mass showed a weaker intensity of labeling than the trophectodermal cells.
authors.affiliation: Center for Cell Therapy and Tissue Repair, VUZV Labs., Prague 10, Czech Republic and ISCARE IVF, Prague 9, Czech Republic.
authors.forename: Helena
authors.initials: H
authors.lastname: Fulka
authors.forename: Milan
authors.initials: M
authors.lastname: Mrazek
authors.forename: Olga
authors.initials: O
authors.lastname: Tepla
authors.forename: Josef
authors.initials: J
authors.lastname: Fulka
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000378:metabolism; D002478:Cells, Cultured; D002843:Chromatin / Q000378:metabolism*; D019175:DNA Methylation; D005220:Fathers; D005260:Female; D005307:Fertilization in Vitro; D020868:Gene Silencing; D006801:Humans; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008856:Microscopy, Fluorescence; D014327:Trophoblasts / Q000378:metabolism; D015053:Zygote / Q000378:metabolism*
chemical_list: D002843:Chromatin