Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Establishment of the DNA methylation landscape of mammalian oocytes, mediated by the DNMT3A-DNMT3L complex, is crucial for reproduction and development. In mouse oocytes, high levels of DNA methylation occur exclusively in the transcriptionally active regions, with moderate to low levels of methylation in other regions. Histone H3K36me3 mediates the high levels of methylation in the transcribed regions; however, it is unknown which histone mark guides the methylation in the other regions. Here, we show that, in mouse oocytes, H3K36me2 is highly enriched in the X chromosome and is broadly distributed across all autosomes. Upon H3K36me2 depletion, DNA methylation in moderately methylated regions is selectively affected, and a methylation pattern unique to the X chromosome is switched to an autosome-like pattern. Furthermore, we find that simultaneous depletion of H3K36me2 and H3K36me3 results in global hypomethylation, comparable to that of DNMT3A depletion. Therefore, the two histone marks jointly provide the chromatin platform essential for guiding DNMT3A-dependent DNA methylation in mouse oocytes.

DOI： 10.1038/s41467-022-32141-2

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Two classes of replication intermediates have been observed from mitochondrial DNA (mtDNA) in many mammalian tissue and cells with two-dimensional agarose gel electrophoresis. One is assigned to leading-strand synthesis in the absence of synchronous lagging-strand synthesis (strand-asynchronous replication), and the other has properties of coupled leading- and lagging-strand synthesis (strand-coupled replication). While strand-asynchronous replication is primed by long noncoding RNA synthesized from a defined transcription initiation site, little is known about the commencement of strand-coupled replication. To investigate it, we attempted to abolish strand-asynchronous replication in cultured human cybrid cells by knocking out the components of the transcription initiation complexes, mitochondrial transcription factor B2 (TFB2M/mtTFB2) and mitochondrial RNA polymerase (POLRMT/mtRNAP). Unexpectedly, removal of either protein resulted in complete mtDNA loss, demonstrating for the first time that TFB2M and POLRMT are indispensable for the maintenance of human mtDNA. Moreover, a lack of TFB2M could not be compensated for by mitochondrial transcription factor B1 (TFB1M/mtTFB1). These findings indicate that TFB2M and POLRMT are crucial for the priming of not only strand-asynchronous but also strand-coupled replication, providing deeper insights into the molecular basis of mtDNA replication initiation.

DOI： 10.1016/j.bbamcr.2021.119167

PubMed

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Histone lysine-to-methionine (K-to-M) mutations have been identified as driver mutations in human cancers. Interestingly, these 'oncohistone' mutations inhibit the activity of histone methyltransferases. Therefore, they can potentially be used as versatile tools to investigate the roles of histone modifications. In this study, we generated a genetically engineered mouse line in which an H3.3K36M mutation could be induced in the endogenous H3f3b gene. Since H3.3K36M has been identified as a causative mutation of human chondroblastoma, we induced this mutation in the chondrocyte lineage in mouse embryonic limbs. We found that H3.3K36M causes a global reduction in H3K36me2 and defects in chondrocyte differentiation. Importantly, the reduction of H3K36me2 was accompanied by a collapse of normal H3K27me3 distribution. Furthermore, the changes in H3K27me3, especially the loss of H3K27me3 at gene regulatory elements, were associated with the mis-regulated expression of a set of genes important for limb development, including HoxA cluster genes. Thus, through the in vivo induction of the H3.3K36M mutation, we reveal the importance of maintaining the balance between H3K36me2 and H3K27me3 during chondrocyte differentiation and limb development.

DOI： 10.1080/15592294.2020.1841873

PubMed

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Epigenetic reprogramming of the zygote involves dynamic incorporation of histone variant H3.3. However, the genome-wide distribution and dynamics of H3.3 during early development remain unknown. Here, we delineate the H3.3 landscapes in mouse oocytes and early embryos. We unexpectedly identify a non-canonical H3.3 pattern in mature oocytes and zygotes, in which local enrichment of H3.3 at active chromatin is suppressed and H3.3 is relatively evenly distributed across the genome. Interestingly, although the non-canonical H3.3 pattern forms gradually during oogenesis, it quickly switches to a canonical pattern at the two-cell stage in a transcription-independent and replication-dependent manner. We find that incorporation of H3.1/H3.2 mediated by chromatin assembly factor CAF-1 is a key process for the de novo establishment of the canonical pattern. Our data suggest that the presence of the non-canonical pattern and its timely transition toward a canonical pattern support the developmental program of early embryos.

DOI： 10.1038/s41594-020-00521-1

PubMed

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Placental development is a key event in mammalian reproduction and embryogenesis. However, the molecular basis underlying placental development is not fully understood. Here, we conduct a forward genetic screen to identify regulators for extraembryonic development and identify Zfp281 as a key factor. Zfp281 overexpression in mouse embryonic stem cells facilitates the induction of trophoblast stem-like cells. Zfp281 is preferentially expressed in the undifferentiated trophoblast stem cell population in an FGF-dependent manner, and disruption of Zfp281 in mice causes severe defects in early placental development. Consistently, Zfp281-depleted trophoblast stem cells exhibit defects in maintaining the transcriptome and differentiation capacity. Mechanistically, Zfp281 interacts with MLL or COMPASS subunits and occupies the promoters of its target genes. Importantly, ZNF281, the human ortholog of this factor, is required to stabilize the undifferentiated status of human trophoblast stem cells. Thus, we identify Zfp281 as a conserved factor for the maintenance of trophoblast stem cell plasticity.

DOI： 10.1016/j.celrep.2019.04.028

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Unlike pluripotent cells, which generate only embryonic tissues, totipotent cells can generate a full organism, including extra-embryonic tissues. A rare population of cells resembling 2-cell-stage embryos arises in pluripotent embryonic stem (ES) cell cultures. These 2-cell-like cells display molecular features of totipotency and broader developmental plasticity. However, their specific nature and the process through which they arise remain outstanding questions. Here we identified intermediate cellular states and molecular determinants during the emergence of 2-cell-like cells. By deploying a quantitative single-cell expression approach, we identified an intermediate population characterized by expression of the transcription factor ZSCAN4 as a precursor of 2-cell-like cells. By using a small interfering RNA (siRNA) screen, we identified epigenetic regulators of 2-cell-like cell emergence, including the non-canonical PRC1 complex PRC1.6 and the EP400-TIP60 complex. Our data shed light on the mechanisms that underlie exit from the ES cell state toward the formation of early-embryonic-like cells in culture and identify key epigenetic pathways that promote this transition.

DOI： 10.1038/s41588-017-0016-5

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Polarized epithelial cells exhibit a characteristic array of microtubules that are oriented along the apicobasal axis of the cells. The minus-ends of these microtubules face apically, and the plus-ends face toward the basal side. The mechanisms underlying this epithelial-specific microtubule assembly remain unresolved, however. Here, using mouse intestinal cells and human Caco-2 cells, we show that the microtubule minus-end binding protein CAMSAP3 (calmodulin-regulated-spectrin-associated protein 3) plays a pivotal role in orienting the apical-to-basal polarity of microtubules in epithelial cells. In these cells, CAMSAP3 accumulated at the apical cortices, and tethered the longitudinal microtubules to these sites. Camsap3 mutation or depletion resulted in a random orientation of these microtubules; concomitantly, the stereotypic positioning of the nucleus and Golgi apparatus was perturbed. In contrast, the integrity of the plasma membrane was hardly affected, although its structural stability was decreased. Further analysis revealed that the CC1 domain of CAMSAP3 is crucial for its apical localization, and that forced mislocalization of CAMSAP3 disturbs the epithelial architecture. These findings demonstrate that apically localized CAMSAP3 determines the proper orientation of microtubules, and in turn that of organelles, in mature mammalian epithelial cells.

DOI： 10.1073/pnas.1520638113

PubMed

Language：English   Publishing type：(MISC) Summary of the papers read (international conference)   Publisher：GENETICS SOC JAPAN  

Web of Science

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Cellular plasticity is essential for early embryonic cells. Unlike pluripotent cells, which form embryonic tissues, totipotent cells can generate a complete organism including embryonic and extraembryonic tissues. Cells resembling 2-cell-stage embryos (2C-like cells) arise at very low frequency in embryonic stem (ES) cell cultures. Although induced reprogramming to pluripotency is well established, totipotent cells remain poorly characterized, and whether reprogramming to totipotency is possible is unknown. We show that mouse 2C-like cells can be induced in vitro through downregulation of the chromatin-assembly activity of CAF-1. Endogenous retroviruses and genes specific to 2-cell embryos are the highest-upregulated genes upon CAF-1 knockdown. Emerging 2C-like cells exhibit molecular characteristics of 2-cell embryos and higher reprogrammability than ES cells upon nuclear transfer. Our results suggest that early embryonic-like cells can be induced by modulating chromatin assembly and that atypical histone deposition may trigger the emergence of totipotent cells.

DOI： 10.1038/nsmb.3066

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Almost half of our genome is occupied by transposable elements. Although most of them are inactive, one type of non-long terminal repeat (LTR) retrotransposon, long interspersed nuclear element 1 (LINE1), is capable of retrotransposition. Two studies in this issue, Pezic and colleagues (pp. 1410-1428) and Castro-Diaz and colleagues (pp. 1397-1409), provide novel insight into the regulation of LINE1s in human embryonic stem cells and mouse germ cells and shed new light on the conservation of complex mechanisms to ensure silencing of transposable elements in mammals.

DOI： 10.1101/gad.246462.114

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The fusion of the gametes upon fertilization results in the formation of a totipotent cell. Embryonic chromatin is expected to be able to support a large degree of plasticity. However, whether this plasticity relies on a particular conformation of the embryonic chromatin is unknown. Moreover, whether chromatin plasticity is functionally linked to cellular potency has not been addressed. Here, we adapted fluorescence recovery after photobleaching (FRAP) in the developing mouse embryo and show that mobility of the core histones H2A, H3.1, and H3.2 is unusually high in two-cell stage embryos and decreases as development proceeds. The transition toward pluripotency is accompanied by a decrease in histone mobility, and, upon lineage allocation, pluripotent cells retain higher mobility than the differentiated trophectoderm. Importantly, totipotent two-cell-like embryonic stem cells also display high core histone mobility, implying that reprogramming toward totipotency entails changes in chromatin mobility. Our data suggest that changes in chromatin dynamics underlie the transitions in cellular plasticity and that higher chromatin mobility is at the nuclear foundations of totipotency.

DOI： 10.1101/gad.238881.114

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

The 21st century started with an important discovery that a pluripotent stem cell can be induced from differentiated cells by 'simply' introducing a few transcription factors. Because pluripotent embryonic stem cells can be stably maintained in culture and also induced, the mechanisms as to how cells maintain and acquire pluripotency have been extensively interrogated. In contrast, how cells maintain or acquire totipotency and the cell potency that exists in the zygote are still poorly understood. To address this question, it is necessary to capture the features that reside in totipotent cells. Here, we review recent results, which shed light on the unique epigenetic state in totipotent cells, and discuss how totipotency is regulated before finding its way towards pluripotency.

DOI： 10.1016/j.gde.2013.06.006

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Willin is a FERM-domain protein, which is related to the Drosophila Expanded, a protein known to be a component of the Hippo signaling pathway. We recently showed that Willin localizes at the apical junctional complex (AJC) in epithelial cells together with Par3 and regulates the contractility of the circumferential actomyosin cables by recruiting aPKC to the AJC. However, it remains unresolved how Willin becomes associated with the AJC. Here, we report that Willin binds to nectins, Ig-family proteins, which also localize at the AJC via their homophilic or heterophilic interactions, and this binding participates in the junctional recruitment of Willin. In addition, we report that the positioning of nectins at the AJC is dependent on their binding to afadin. Thus, our results suggest that the nectin-afadin interaction plays a role in the correct localization of Willin.

DOI： 10.1111/j.1365-2443.2012.01593.x

PubMed

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

The zonula adherens (ZA), a type of adherens junction (AJ), plays a major role in epithelial cell-cell adhesions. It remains unknown how the ZA is remodeled during epithelial reorganization. Here we found that the ZA was converted to another type of AJ with punctate morphology (pAJ) at the margins of epithelial colonies. The F-actin-stabilizing protein EPLIN (epithelial protein lost in neoplasm), which functions to maintain the ZA via its association with αE-catenin, was lost in the pAJs. Consistently, a fusion of αE-catenin and EPLIN contributed to the formation of ZA but not pAJs. We show that junctional tension was important for retaining EPLIN at AJs, and another force derived from actin fibers laterally attached to the pAJs inhibited EPLIN-AJ association. Vinculin was required for general AJ formation, and it cooperated with EPLIN to maintain the ZA. These findings suggest that epithelial cells remodel their junctional architecture by responding to mechanical forces, and the αE-catenin-bound EPLIN acts as a mechanosensitive regulator for this process.

DOI： 10.1083/jcb.201104124

PubMed

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Apical-domain constriction is important for regulating epithelial morphogenesis. Epithelial cells are connected by apical junctional complexes (AJCs) that are lined with circumferential actomyosin cables. The contractility of these cables is regulated by Rho-associated kinases (ROCKs). Here, we report that Willin (a FERM-domain protein) and Par3 (a polarity-regulating protein) cooperatively regulate ROCK-dependent apical constriction. We found that Willin recruits aPKC and Par6 to the AJCs, independently of Par3. Simultaneous depletion of Willin and Par3 completely removed aPKC and Par6 from the AJCs and induced apical constriction. Induced constriction was through upregulation of the level of AJC-associated ROCKs, which was due to loss of aPKC. Our results indicate that aPKC phosphorylates ROCK and suppresses its junctional localization, thereby allowing cells to retain normally shaped apical domains. Thus, we have uncovered a Willin/Par3-aPKC-ROCK pathway that controls epithelial apical morphology.

DOI： 10.1038/ncb2274

PubMed

Language：English   Publishing type：(MISC) Summary of the papers read (international conference)   Publisher：ELSEVIER SCIENCE BV  

DOI： 10.1016/j.mod.2009.06.172

Web of Science

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Presentation type：Oral presentation(invited, special)  

Event date： 2022.6

Language：Japanese   Presentation type：Symposium workshop panel(nominated)  

Language：Japanese   Presentation type：Symposium workshop panel(nominated)  

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Event date： 2021.12

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：オンライン  

Event date： 2021.12

Language：Japanese   Presentation type：Symposium workshop panel(nominated)  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：オンライン  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Language：Japanese   Presentation type：Symposium workshop panel(nominated)  

Event date： 2021.9

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Event date： 2020.12

Language：English   Presentation type：Symposium workshop panel(nominated)  

Language：English   Presentation type：Symposium workshop panel(nominated)