scholarly journals 116 ACTIVE METHYLATION AND ACETYLATION OF HISTONE H3-K9 IN MOUSE EMBRYO WITH DIFFERENT PROPORTIONS OF MATERNAL AND PATERNAL GENOME

2005 ◽  
Vol 17 (2) ◽  
pp. 208
Author(s):  
V.T. Nguyen ◽  
S. Wakayama ◽  
H.-T. Bui ◽  
T. Wakayama
Keyword(s):  
Early Development ◽  
Nuclear Transfer ◽  
Early Stage ◽  
Epigenetic Modification ◽  
Histone H3 ◽  
Paternal Genome ◽  
Somatic Nucleus ◽  
Histone H3 Methylation ◽  
Cell Embryo ◽  
Somatic Nuclear Transfer

Epigenetic modification of parental genomes plays a prominent role in regulating genome expression in the early development of embryos. In general, histone H3 of the paternal genome is demethylated at lysine 9 (H3-K9) during the first and second mitotic divisions in fertilized embryos, while the maternal genome is methylated. We investigated the effects of maternal genomes (Mgen) and paternal genomes (Pgen) on H3-K9 methylation and acetylation during the early development of murine embryos. Histone H3-K9 methylation and acetylation were detected by anti-trimethyl histone H3-K9 and anti-triacetyl histone H3-K9 antibodies. The following embryos were used in this study: (1) intracytoplasmic sperm injection (ICSI) embryos (50% Mgen, 50% Pgen); (2) parthenogenetic diploid embryos (100% Mgen, 0% Pgen); (3) somatic nuclear transfer embryos (50% Mgen, 50% Pgen from previous generation); (4) androgenetic diploid embryos (0% Mgen, 100% Pgen); and (5) haploidized somatic nucleus and sperm embryo (about 25% Mgen, about 75% Pgen). Each experiment was repeated five times to obtain more than 120 embryos per group. Our results show that: (1) in the ICSI embryo, histone H3 methylation occurs in Mgen but not in Pgen at the first and second mitotic divisions; (2) in the parthenogenetic embryo, histone H3 methylation occurs in both nuclei at the first and second mitotic divisions; (3) in the somatic nuclear transfer embryo, histone H3 is methylated in all of the nuclei at the first and second mitotic divisions; (4) in the androgenetic embryo, methylated H3-K9 is detected weakly in the heterochromatin enclosed around the nucleolus of the pronuclei of the one-cell embryo, and methylated in the entire nuclei of the two-cell embryo; and (5) in the haploidized somatic and sperm embryo, the pattern of histone H3-L9 methylation resembles that of the ICSI embryo. While histone H3-K9 acetylation occurs in both paternal and maternal genomes during interphase, even when the nuclear membrane is completely degraded and the chromosome is condensed, it disappears rapidly when the chromosome enters the real metaphase, and reappears at the early stage of pronuclear formation in all types of embryo. These results suggest that the absence of maternal genomes results in histone H3-K9 methylation in the paternal genomes during the first and second mitotic divisions of embryos in mice. In addition, histone H3-K9 acetylation is independent of the presence or absence of maternal or paternal genomes during pre-implantation development in mice. This study was supported by grants-in-aid for Creative Scientific Research (13GS0008) and a project for the realization of regenerative medicine (the research field for the technical development of stem cell manipulation) to T.W. from MEXT, Japan.

scholarly journals Inheritance of Histone H3 Methylation in Reprogramming of Somatic Nuclei Following Nuclear Transfer

2008 ◽  
Vol 54 (3) ◽  
pp. 233-238 ◽  
Author(s):  
Gen-Bao SHAO ◽  
Hong-Mei DING ◽  
Ai-Hua GONG ◽  
De-Sheng XIAO
Keyword(s):  
Nuclear Transfer ◽  
Histone H3 ◽  
Histone H3 Methylation

131 DYNAMICS OF HISTONE H3 METHYLATION AT POSITIONS K4 AND K9 IN MOUSE, RABBIT, AND BOVINE PRE-IMPLANTATION EMBRYOS

2006 ◽  
Vol 18 (2) ◽  
pp. 174 ◽  
Author(s):  
K. Lepikhov ◽  
F. Yang ◽  
C. Wrenzycki ◽  
V. Zakhartchenko ◽  
H. Niemann ◽  
...  
Keyword(s):  
Histone H3 ◽  
Distribution Patterns ◽  
Blastocyst Stage ◽  
Dna Demethylation ◽  
Preimplantation Embryos ◽  
Staining Procedure ◽  
Cell Stage ◽  
Paternal Genome ◽  
Histone H3 Methylation ◽  
Rabbit Embryos

In mammals, upon the penetration of sperm into the oocyte, the paternal genome undergoes dramatic epigenetic changes. Protamin packaging of DNA is replaced by histones that acquire specific modifications. In mouse zygotes, paternal DNA gets rapidly demethylated by an active mechanism. In bovine zygotes the methylation from paternal DNA is erased only partially, and in rabbit zygotes it persists at the initial level. To understand whether these reprogramming differences are also reflected in histone modifications, we examined the dynamic changes of histone H3 methylation at positions K4 and K9 in mouse, bovine, and rabbit zygotes and in preimplantation embryos using an immunofluorescence staining procedure (Lepikhov and Walter 2004 BMC Dev. Biol. 4, 12). In zygotes, maternal chromatin contains both types of histone H3 methylation. After fertilization protamines in sperm are very quickly replaced by histones. After the formation of nucleosomes, histone H3 acquires methylation at position K4 in a stepwise manner: first as mono-methylated form and later as tri-methylated. In the late zygote, both paternal and maternal pronuclei show equal levels of histone H3 methylation at position K4. Regardless of the differences in DNA reprogramming in these 3 species, H3/K9 di-methylation is not detected on paternal genomes and is only associated with maternal genomes. During the subsequent cleavage stages, H3/K9 di-methylation decreases gradually and becomes hardly detectable in 4-cell bovine and rabbit embryos. In mouse embryos, it is detectable through all the stages. Bovine embryos reacquire this type of modification at the 8-16 cell stage, and it remains at the very low levels in rabbit, embryos until the blastocyst stage. In conclusion, mouse, rabbit and bovine zygotes show similar patterns of H3/K4triMe and H3/K9diMe distribution despite the difference in paternal DNA demethylation. The dynamics of H3/K9diMe distribution patterns in cleavage stage embryos from all embryos do not correlate with embryonic genomic activation events.

98 HETEROCHROMATIN REPROGRAMMING IN MOUSE EARLY DEVELOPMENT

2009 ◽  
Vol 21 (1) ◽  
pp. 149
Author(s):  
T. Wongtawan ◽  
J. Taylor ◽  
I. Wilmut ◽  
S. Pennings
Keyword(s):  
Gene Expression ◽  
Early Development ◽  
Nuclear Transfer ◽  
Technical Assistance ◽  
Es Cells ◽  
Cell Nuclei ◽  
Mouse Development ◽  
Fluorescent Intensity ◽  
Chromatin Architecture ◽  
Somatic Nuclear Transfer

Heterochromatin is essential for epigenetic gene silencing and nuclear chromatin architecture. Early mouse development is accompanied by dynamic epigenetic changes and heterochromatin restructuring in the cell nuclei of cleavage stage embryos. We have previously shown that disruption of heterochromatin markers such as DNA methylation following somatic nuclear transfer causes developmental failure (Beaujean N et al. 2004 Biol. Reprod. 71, 185–193). The aim of the present study was to investigate the transitions and maturation of heterochromatin during normal development to improve nuclear reprogramming technology and understand developmental abnormalities caused by epigenetic alterations in somatic nuclear transfer and assisted reproductive procedures. Mouse pre- and post-implantation embryos and ES cells from B6CBAF1 mice were used in experiments employing the following methodologies. Embryos and ES cells were stained by immunofluorescence to detect heterochromatin proteins and epigenetic markers. Images were captured using laser confocal microscopy. Relative quantification of fluorescent intensity was performed using Zeiss LSM-meta and WCIF-ImageJ software. mRNA of Histone methyltransferase (HMTase), suv39h, suv420h, ehmt, eset, and demethyltransferase (DHMTase), jmjd1a, jmjd2a, jmjd2c were quantified by real-time PCR. siRNA and specific inhibitors were used to study the function of suv39h, ehmt2, jmjd2c genes that may be responsible for heterochromatin reprogramming. Our results demonstrated that H3K9me3, H3K9me2, H4K20me2, H4K20me3, HP1α and HP1β are reprogrammed during early development. The gene expression results showed the dynamic and temporal gene expression of HMTases and DHMTase during development. Inhibition of Ehmt2 and jmjd2c caused preimplantation developmental arrest. Furthermore, we found chromatin modification differences in the heterochromatin of ES cells, ICM and epiblast. We conclude that heterochromatin reprogramming might be essential for development because it may contribute to chromatin architecture, thus influencing gene expression. HMTases and DHTMases could be implicated in the mechanism of heterochromatin reprogramming. It is possible that Ehmt2 and jmjd2c play an important role in preimplantation development by modifying chromatin globally and at the local gene level. This work was supported by a The Royal Thai Studentship. We acknowledge the contributions of technical assistance from T. O’Connor, B. Wongtawan and P. Travers.

Sign in / Sign up

Export Citation Format

Share Document