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Changes in histone acetylation during mouse oocyte meiosis.

Kim JM, Liu H, Tazaki M, Nagata M, Aoki F - J. Cell Biol. (2003)

Bottom Line: When the somatic cell nuclei were transferred into enucleated oocytes, the acetylation of lysines decreased markedly.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8562, Japan. aokif@k.u-tokyo.ac.jp

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.

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Deacetylation of histones in transferred nuclei and chromosomes. The enucleated oocytes were transplanted with interphase nuclei (A) or metaphase chromosomes (B) of NIH 3T3 cells. NIH 3T3 cells were embedded in the perivitelline space of enucleated oocytes (embedded). Both during and after the electrofusion procedures, the enucleated oocytes and reconstructed embryos were treated with either 75 nM TSA (NT+TSA) or without TSA (NT). 2 h after electrofusion, the oocytes were subjected to immunostaining with the anti–acetyl histone H3/lysine 14 (H3/K14) or the anti–acetyl histone H4/lysine 12 (H4/K12) antibodies. Each sample was counterstained with DAPI. The deacetylation of lysine 9 on histone H3 and lysines 8 and 16 on histone H4 in the transplanted nucleus is shown in Fig. S7, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1. The fluorescence signal of the antibody was quantified, and the results are shown in Fig. S8, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1.
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fig5: Deacetylation of histones in transferred nuclei and chromosomes. The enucleated oocytes were transplanted with interphase nuclei (A) or metaphase chromosomes (B) of NIH 3T3 cells. NIH 3T3 cells were embedded in the perivitelline space of enucleated oocytes (embedded). Both during and after the electrofusion procedures, the enucleated oocytes and reconstructed embryos were treated with either 75 nM TSA (NT+TSA) or without TSA (NT). 2 h after electrofusion, the oocytes were subjected to immunostaining with the anti–acetyl histone H3/lysine 14 (H3/K14) or the anti–acetyl histone H4/lysine 12 (H4/K12) antibodies. Each sample was counterstained with DAPI. The deacetylation of lysine 9 on histone H3 and lysines 8 and 16 on histone H4 in the transplanted nucleus is shown in Fig. S7, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1. The fluorescence signal of the antibody was quantified, and the results are shown in Fig. S8, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1.

Mentions: It has been established that the cytoplasm of the MII-stage oocyte is able to reprogram the gene expression pattern of transferred somatic nuclei (Wilmut et al., 1997; Rideout et al., 2001). If we assume that the acetylation of histones H3 and/or H4 is involved in the inheritance of gene expression patterns, then these histones from somatic nuclei should be deacetylated in oocytes. To address this issue, the nuclei of NIH 3T3 cells were transferred into enucleated MII-stage oocytes, and changes in the histone acetylation levels were examined. 2 h after the transfer, the interphase nucleus underwent premature chromosome condensation. In this chromosome, the signals for the antihistone antibodies decreased dramatically (Fig. 5Figure 5.


Changes in histone acetylation during mouse oocyte meiosis.

Kim JM, Liu H, Tazaki M, Nagata M, Aoki F - J. Cell Biol. (2003)

Deacetylation of histones in transferred nuclei and chromosomes. The enucleated oocytes were transplanted with interphase nuclei (A) or metaphase chromosomes (B) of NIH 3T3 cells. NIH 3T3 cells were embedded in the perivitelline space of enucleated oocytes (embedded). Both during and after the electrofusion procedures, the enucleated oocytes and reconstructed embryos were treated with either 75 nM TSA (NT+TSA) or without TSA (NT). 2 h after electrofusion, the oocytes were subjected to immunostaining with the anti–acetyl histone H3/lysine 14 (H3/K14) or the anti–acetyl histone H4/lysine 12 (H4/K12) antibodies. Each sample was counterstained with DAPI. The deacetylation of lysine 9 on histone H3 and lysines 8 and 16 on histone H4 in the transplanted nucleus is shown in Fig. S7, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1. The fluorescence signal of the antibody was quantified, and the results are shown in Fig. S8, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1.
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Related In: Results  -  Collection

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fig5: Deacetylation of histones in transferred nuclei and chromosomes. The enucleated oocytes were transplanted with interphase nuclei (A) or metaphase chromosomes (B) of NIH 3T3 cells. NIH 3T3 cells were embedded in the perivitelline space of enucleated oocytes (embedded). Both during and after the electrofusion procedures, the enucleated oocytes and reconstructed embryos were treated with either 75 nM TSA (NT+TSA) or without TSA (NT). 2 h after electrofusion, the oocytes were subjected to immunostaining with the anti–acetyl histone H3/lysine 14 (H3/K14) or the anti–acetyl histone H4/lysine 12 (H4/K12) antibodies. Each sample was counterstained with DAPI. The deacetylation of lysine 9 on histone H3 and lysines 8 and 16 on histone H4 in the transplanted nucleus is shown in Fig. S7, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1. The fluorescence signal of the antibody was quantified, and the results are shown in Fig. S8, available at http://www.jcb.org/cgi/content/full/jcb.200303047/DC1.
Mentions: It has been established that the cytoplasm of the MII-stage oocyte is able to reprogram the gene expression pattern of transferred somatic nuclei (Wilmut et al., 1997; Rideout et al., 2001). If we assume that the acetylation of histones H3 and/or H4 is involved in the inheritance of gene expression patterns, then these histones from somatic nuclei should be deacetylated in oocytes. To address this issue, the nuclei of NIH 3T3 cells were transferred into enucleated MII-stage oocytes, and changes in the histone acetylation levels were examined. 2 h after the transfer, the interphase nucleus underwent premature chromosome condensation. In this chromosome, the signals for the antihistone antibodies decreased dramatically (Fig. 5Figure 5.

Bottom Line: When the somatic cell nuclei were transferred into enucleated oocytes, the acetylation of lysines decreased markedly.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8562, Japan. aokif@k.u-tokyo.ac.jp

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.

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