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A critical function of Mad2l2 in primordial germ cell development of mice.

Pirouz M, Pilarski S, Kessel M - PLoS Genet. (2013)

Bottom Line: By the analysis of transfected fibroblasts we found that the interaction of Mad2l2 with the histone methyltransferases G9a and GLP lead to a downregulation of H3K9me2.Together, these results demonstrate the potential of Mad2l2 in the regulation of both cell cycle and the epigenetic status.The function of Mad2l2 is essential in PGCs, and thus of high relevance for fertility.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Cell Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany. mehdi.pirouz@mpibpc.mpg.de

ABSTRACT
The development of primordial germ cells (PGCs) involves several waves of epigenetic reprogramming. A major step is following specification and involves the transition from the stably suppressive histone modification H3K9me2 to the more flexible, still repressive H3K27me3, while PGCs are arrested in G2 phase of their cycle. The significance and underlying molecular mechanism of this transition were so far unknown. Here, we generated mutant mice for the Mad2l2 (Mad2B, Rev7) gene product, and found that they are infertile in both males and females. We demonstrated that Mad2l2 is essential for PGC, but not somatic development. PGCs were specified normally in Mad2l2(-/-) embryos, but became eliminated by apoptosis during the subsequent phase of epigenetic reprogramming. A majority of knockout PGCs failed to arrest in the G2 phase, and did not switch from a H3K9me2 to a H3K27me3 configuration. By the analysis of transfected fibroblasts we found that the interaction of Mad2l2 with the histone methyltransferases G9a and GLP lead to a downregulation of H3K9me2. The inhibitory binding of Mad2l2 to Cyclin dependent kinase 1 (Cdk1) could arrest the cell cycle in the G2 phase, and also allowed another histone methyltransferase, Ezh2, to upregulate H3K27me3. Together, these results demonstrate the potential of Mad2l2 in the regulation of both cell cycle and the epigenetic status. The function of Mad2l2 is essential in PGCs, and thus of high relevance for fertility.

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Normal DNA demethylation in Mad2l2 deficient PGCs.(A) Whole mount staining of E9.0 embryos (upper panel) and related quantification (lower panel) shows a normal down regulation of Dnmt3b DNA methyltransferase. (B) Immunohistochemistry analysis of embryo sections at E9.0 represents a normal DNA demethylation of both wild type and knockout PGCs (arrowheads). The arrow points to a somatic cell with a high DNA methylation level. “n” represents the total number of PGCs counted in three different embryos per genotype. The data are means ± SD.
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pgen-1003712-g004: Normal DNA demethylation in Mad2l2 deficient PGCs.(A) Whole mount staining of E9.0 embryos (upper panel) and related quantification (lower panel) shows a normal down regulation of Dnmt3b DNA methyltransferase. (B) Immunohistochemistry analysis of embryo sections at E9.0 represents a normal DNA demethylation of both wild type and knockout PGCs (arrowheads). The arrow points to a somatic cell with a high DNA methylation level. “n” represents the total number of PGCs counted in three different embryos per genotype. The data are means ± SD.

Mentions: Immediately after their induction in the epiblast, PGCs begin to undergo massive epigenetic reprogramming with regard to both DNA and histone modifications. The genome-wide demethylation of the DNA in PGCs is partially due to a downregulation DNA methyltransferases, which is accompanied by loss of cytidine methylation. To address the epigenetic reprogramming in Mad2l2−/− PGCs, first we performed whole mount staining (See Text S1) against Dnmt3b DNA methyltransferase. Both wild type and Mad2l2 deficient PGCs suppressed Dnmt3b expression (Figure 4A). Immunohistochemistry analysis of DNA methylation showed loss of the 5-methylcytosine (5 mC) at E9.0 in both wild type and knockout sections (Figure 4B). These observations seem to indicate that DNA hypomethylation had been properly initiated and progressed in the absence of Mad2l2.


A critical function of Mad2l2 in primordial germ cell development of mice.

Pirouz M, Pilarski S, Kessel M - PLoS Genet. (2013)

Normal DNA demethylation in Mad2l2 deficient PGCs.(A) Whole mount staining of E9.0 embryos (upper panel) and related quantification (lower panel) shows a normal down regulation of Dnmt3b DNA methyltransferase. (B) Immunohistochemistry analysis of embryo sections at E9.0 represents a normal DNA demethylation of both wild type and knockout PGCs (arrowheads). The arrow points to a somatic cell with a high DNA methylation level. “n” represents the total number of PGCs counted in three different embryos per genotype. The data are means ± SD.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3757036&req=5

pgen-1003712-g004: Normal DNA demethylation in Mad2l2 deficient PGCs.(A) Whole mount staining of E9.0 embryos (upper panel) and related quantification (lower panel) shows a normal down regulation of Dnmt3b DNA methyltransferase. (B) Immunohistochemistry analysis of embryo sections at E9.0 represents a normal DNA demethylation of both wild type and knockout PGCs (arrowheads). The arrow points to a somatic cell with a high DNA methylation level. “n” represents the total number of PGCs counted in three different embryos per genotype. The data are means ± SD.
Mentions: Immediately after their induction in the epiblast, PGCs begin to undergo massive epigenetic reprogramming with regard to both DNA and histone modifications. The genome-wide demethylation of the DNA in PGCs is partially due to a downregulation DNA methyltransferases, which is accompanied by loss of cytidine methylation. To address the epigenetic reprogramming in Mad2l2−/− PGCs, first we performed whole mount staining (See Text S1) against Dnmt3b DNA methyltransferase. Both wild type and Mad2l2 deficient PGCs suppressed Dnmt3b expression (Figure 4A). Immunohistochemistry analysis of DNA methylation showed loss of the 5-methylcytosine (5 mC) at E9.0 in both wild type and knockout sections (Figure 4B). These observations seem to indicate that DNA hypomethylation had been properly initiated and progressed in the absence of Mad2l2.

Bottom Line: By the analysis of transfected fibroblasts we found that the interaction of Mad2l2 with the histone methyltransferases G9a and GLP lead to a downregulation of H3K9me2.Together, these results demonstrate the potential of Mad2l2 in the regulation of both cell cycle and the epigenetic status.The function of Mad2l2 is essential in PGCs, and thus of high relevance for fertility.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Cell Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany. mehdi.pirouz@mpibpc.mpg.de

ABSTRACT
The development of primordial germ cells (PGCs) involves several waves of epigenetic reprogramming. A major step is following specification and involves the transition from the stably suppressive histone modification H3K9me2 to the more flexible, still repressive H3K27me3, while PGCs are arrested in G2 phase of their cycle. The significance and underlying molecular mechanism of this transition were so far unknown. Here, we generated mutant mice for the Mad2l2 (Mad2B, Rev7) gene product, and found that they are infertile in both males and females. We demonstrated that Mad2l2 is essential for PGC, but not somatic development. PGCs were specified normally in Mad2l2(-/-) embryos, but became eliminated by apoptosis during the subsequent phase of epigenetic reprogramming. A majority of knockout PGCs failed to arrest in the G2 phase, and did not switch from a H3K9me2 to a H3K27me3 configuration. By the analysis of transfected fibroblasts we found that the interaction of Mad2l2 with the histone methyltransferases G9a and GLP lead to a downregulation of H3K9me2. The inhibitory binding of Mad2l2 to Cyclin dependent kinase 1 (Cdk1) could arrest the cell cycle in the G2 phase, and also allowed another histone methyltransferase, Ezh2, to upregulate H3K27me3. Together, these results demonstrate the potential of Mad2l2 in the regulation of both cell cycle and the epigenetic status. The function of Mad2l2 is essential in PGCs, and thus of high relevance for fertility.

Show MeSH
Related in: MedlinePlus