Differential acetylation of histone H4 lysine during development of in vitro fertilized, cloned and parthenogenetically activated bovine embryos

• DOI: 10.4161/epi.3.4.6497
• Publication Date: 2010-06-09T10:34:54Z
• Authors: Walid E. Maalouf; Ramiro Alberio; Keith H. Campbell
• Keywords: Pronucleus; Histone H4; Male pronucleus; Histone Methylation

The oocyte is remarkable in its ability to remodel parental genomes following fertilization and reprogram somatic nuclei after nuclear transfer (NT). To characterise the patterns of histone H4 acetylation DNA methylation during development bovine gametogenesis embryogenesis, specific antibodies for acetylated at lysine 5 (K5), K8, K12 K16 residues methylated cytosine CpG dinucleotides were used. Oocytes sperm lacked staining acetylation, when was intense. In IVF zygotes, both pronuclei transiently hyper-acetylated. However, male pronucleus faster acquiring histones, concurrently it rapidly demethylated. Both equally S G2-phase transition, while only still observed female pronucleus. parthenogenetically activated oocytes, enriched faster, remained methylated. A transient de-acetylation NT embryos reconstructed using a non-activated ooplast metaphase second arrested oocyte. Remarkably, intensity most peaked 8-cell stage embryos, which coincided with zygotic genome activation lowest staining. At blastocyst stage, trophectodermal cells parthenogenetic generally demonstrated more intense lysine, whilst ICM stained very weakly. contrast intensely ICM. blastocysts showed differential blastomeres but not methylation. inverse association different vital embryo stages suggests mechanistically significant relationship. complexities these epigenetic interactions are discussed.