Chromatin structure and de novo methylation of sperm DNA: implications for activation of the paternal genome

DNA methylation at CpG dinucleotides is an important epigenetic regulation process, which is associated with gene expression without any change in DNA sequence. During early development of the mouse embryo, dynamic changes in DNA methylation of the genome occur. After fertilization, active demethylation occurs on the paternal genome followed by passive demethylation until morula stage and then de novo methylation at the blastocyst stage. This study was designed to investigate changes in DNA methylation of in vivo- and in vitro-fertilized (IVF) porcine embryos. DNA methylation states were observed in preimplantation porcine embryos by using an immunofluorescence method after staining with an antibody against 5-methylcytosine. In contrast to the data from mouse embryos, active demethylation of the genome from the paternal pronucleus was not observed in the porcine embryos. Also, no passive demethylation was detected in in vivo- and IVF-derived embryos until the morula stage. Moreover, differential de novo methylation was not shown on the genome of the inner cell mass. Whole genomes of inner cell mass and trophectoderm cells were fully methylated. Our results demonstrate that DNA methylation of porcine embryos is different from that of mouse embryos during preimplantation development, suggesting that the machinery to regulate DNA methylation may be species-specific in mammals.

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Altered chromatin condensation of heat-stressed spermatozoa perturbs the dynamics of DNA methylation reprogramming in the paternal genome after in vitro fertilisation in cattle

Reproduction Fertility and Development ◽

10.1071/rd13218 ◽

2014 ◽

Vol 26 (8) ◽

pp. 1107 ◽

Cited By ~ 17

Author(s):

Mohammad Bozlur Rahman ◽

Md. Mostofa Kamal ◽

Tom Rijsselaere ◽

Leen Vandaele ◽

Mohammed Shamsuddin ◽

...

Keyword(s):

Dna Methylation ◽

De Novo ◽

Chromatin Condensation ◽

Dna Demethylation ◽

In Vitro Fertilisation ◽

Paternal Genome ◽

Time Points ◽

Fertilisation Rate ◽

De Novo Methylation

Shortly after penetration of the oocyte, sperm DNA is actively demethylated, which is required for totipotent zygotic development. Aberrant DNA methylation is thought to be associated with altered chromatin condensation of spermatozoa. The objectives of this study were to investigate the dynamics of DNA methylation reprogramming in the paternal pronucleus and subsequent fertilisation potential of heat-stressed bull spermatozoa having altered chromatin condensation. Hence, bovine zygotes (n = 1239) were collected at three different time points (12, 18 and 24 h post insemination, hpi), and stained with an antibody against 5-methylcytosine. Fluorescence intensities of paternal and maternal pronuclei were measured by ImageJ. DNA methylation patterns in paternal pronuclei derived from heat-stressed spermatozoa did not differ between time points (P > 0.05), whereas control zygotes clearly showed demethylation and de novo methylation at 18 and 24 hpi, respectively. Moreover, heat-stressed spermatozoa showed a highly reduced (P < 0.01) fertilisation rate compared with non-heat-stressed or normal control spermatozoa (53.7% vs 70.2% or 81.5%, respectively). Our data show that the normal pattern of active DNA demethylation followed by de novo methylation in the paternal pronucleus is perturbed when oocytes are fertilised with heat-stressed spermatozoa, which may be responsible for decreased fertilisation potential.

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High levels of De Novo methylation and altered chromatin structure at CpG islands in cell lines

Cell ◽

10.1016/0092-8674(90)90015-7 ◽

1990 ◽

Vol 62 (3) ◽

pp. 503-514 ◽

Cited By ~ 411

Author(s):

Francisco Antequera ◽

Joan Boyes ◽

Adrian Bird

Keyword(s):

Cell Lines ◽

Chromatin Structure ◽

De Novo ◽

Cpg Islands ◽

De Novo Methylation

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Faculty Opinions recommendation of DNA methyltransferase loading, but not de novo methylation, is an oocyte-autonomous process stimulated by SCF signalling.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1116729.572800 ◽

2008 ◽

Author(s):

Richard J Chaillet

Keyword(s):

Dna Methyltransferase ◽

De Novo ◽

De Novo Methylation

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Induction of Promoter DNA Methylation Upon High-Pressure Spraying of Double-Stranded RNA in Plants

Agronomy ◽

10.3390/agronomy11040789 ◽

2021 ◽

Vol 11 (4) ◽

pp. 789

Author(s):

Athanasios Dalakouras ◽

Ioannis Ganopoulos

Keyword(s):

High Pressure ◽

De Novo ◽

Epigenetic Changes ◽

Double Stranded Rna ◽

Rna Molecules ◽

Promoter Sequences ◽

Promoter Dna Methylation ◽

Promoter Dna ◽

First Time ◽

De Novo Methylation

Exogenous application of RNA molecules is a potent method to trigger RNA interference (RNAi) in plants in a transgene-free manner. So far, all exogenous RNAi (exo-RNAi) applications have aimed to trigger mRNA degradation of a given target. However, the issue of concomitant epigenetic changes was never addressed. Here, we report for the first time that high-pressure spraying of dsRNAs can trigger de novo methylation of promoter sequences in plants.

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