Changes in histone acetylation during mouse oocyte meiosis

Abstract

We examined global changes in the acetylation of histones in mouse oocytes during meiosis. Immunocytochemistry with specific antibodies against various acetylated lysine residues on histones H3 and H4 showed that acetylation of all the lysines decreased to undetectable or negligible levels in the oocytes during meiosis, whereas most of these lysines were acetylated during mitosis in preimplantation embryos and somatic cells. When the somatic cell nuclei were transferred into enucleated oocytes, the acetylation of lysines decreased markedly. This type of deacetylation was inhibited by trichostatin A, a specific inhibitor of histone deacetylase (HDAC), thereby indicating that HDAC is able to deacetylate histones during meiosis but not during mitosis. Meiosis-specific deacetylation may be a consequence of the accessibility of HDAC1 to the chromosome, because HDAC1 colocalized with the chromosome during meiosis but not during mitosis. As histone acetylation is thought to play a role in propagating the gene expression pattern to the descendent generation during mitosis, and the gene expression pattern of differentiated oocytes is reprogrammed during meiosis to allow the initiation of a new program by totipotent zygotes of the next generation, our results suggest that the oocyte cytoplasm initializes a program of gene expression by deacetylating histones.

Messenger RNA expression patterns of histone‐associated genes in bovine preimplantation embryos derived from different origins

“…In contrast, we detected mRNA for HDAC2 from single oocytes or embryos. Moreover, Kim et al (2003) demonstrated that the global acetylation level of various lysine residues at H3 and H4 decreased in mouse oocytes during meiosis suggesting that HDACs activity plays an important role in the reprogramming of gene expression in oocytes. Results from the present study have shown that ZAR1 transcripts are exclusively derived from the maternal genome in bovine preimplantation embryos which is similar to previous findings for bovine and mouse embryos (Wu et al, 2003a;Pennetier et al, 2004;Uzbekova et al, 2006).…”

HDAC1 and HDAC2 in mouse oocytes and preimplantation embryos: Specificity versus compensation

“…Histone deacetylation accompanies oocyte maturation and inhibiting HDAC activity with TSA results in global histone hyperacetylation and chromosome segregation defects. [65][66][67][68] The responsible HDACs, however, have not been fully identified.…”

“…46 No changes of histone acetylation are observed in the Hdac1 mutant eggs, 46 demonstrating that HDAC1 is not required for histone deacetylation during oocyte maturation although HDAC1 is associated with chromosome during the process. 42,43,65 Deletion of Hdac2 leads to global histone hyperacetylation in growing oocytes and hyperacetyation of histone H4K16 in MII eggs, which is linked with disruption of a normal chromatin configuration. 46 Acetylation of H4K16 inhibits formation of the higher order 30 nm chromatin structure, and loss of H4K16 shows defects equivalent to the loss of the H4 tails.…”

Nuclear reprogramming: the strategy used in normal development is also used in somatic cell nuclear transfer and parthenogenesis

“…It explains the observation that a substantial proportion of nt-embryos retains a variable amount of ectopic gene expression and aberrant epigenetic memory related to the developmental history of the nuclear donors [7][8][9][10][11][12]15], and the observation that after embryo reconstruction a prolonged pre-incubation time, which presumably facilitates CF dissociation and possibly removal of other epigenetic marks, often leads to better reprogramming [30,31] The global dissociation and re-association of CFs from chromatin occur in parallel with other reprogramming processes, e.g. DNA demethylation [38] and histone deacetylation [29,39] during SCNT. The combinatorial effect of these processes resets the somatic nuclei to that of the embryo.…”