| 野上 順平（のがみ じゅんぺい） | データ更新日：2023.11.22 |
助教 ／
医学研究院
| 1. | Kensuke Sasaki, Takuji Yamauchi, Yuichiro Semba, Jumpei Nogami, Hiroshi Imanaga, Tatsuya Terasaki, Fumihiko Nakao, Koshi Akahane, Takeshi Inukai, ELs Verhoeyen, Koichi Akashi, Takahiro Maeda, Genome-wide CRISPR-Cas9 screen identifies rationally designed combination therapies for CRLF2-rearranged Ph-like ALL, Blood, 10.1182/blood.2021012976, 2021.09, Acute lymphoblastic leukemia (ALL) harboring the IgH-CRLF2 rearrangement (IgH-CRLF2-r) exhibits poor clinical outcomes and is the most common subtype of Ph-like ALL. While multiple chemotherapeutic regimens, including Ruxolitinib monotherapy and/or its combination with chemotherapy, are being tested, their efficacy is reportedly limited. To identify molecules/pathways relevant for IgH-CRLF2-r ALL pathogenesis, we performed genome-wide CRISPR-Cas9 dropout screens in the presence or absence of Ruxolitinib using two IgH-CRLF2-r ALL lines that differ in RAS mutational status. To do so, we employed a baboon envelope pseudotyped lentiviral vector system, which enabled, for the first time, highly efficient transduction of human B cells. While sgRNAs targeting CRLF2, IL7RA or JAK1/2 significantly affected cell fitness in both lines, those targeting STAT5A, STAT5B or STAT3 did not, suggesting that STAT signaling is largely dispensable for IgH-CRLF2-r ALL cell survival. We show that regulators of RAS signaling are critical for cell fitness and Ruxolitinib sensitivity and that CRKL depletion enhances Ruxolitinib sensitivity in RAS wild-type (WT) cells. Gilteritinib, a pan-tyrosine kinase inhibitor that blocks CRKL phosphorylation, effectively killed RAS WT IgH-CRLF2-r ALL cells in vitro and in vivo, either alone or combined with Ruxolitinib. We further show that combining Gilteritinib with Trametinib, a MEK1/2 inhibitor, is an effective means to target IgH-CRLF2-r ALL cells regardless of RAS mutational status. Our study delineates molecules/pathways relevant for CRLF2-r ALL pathogenesis and could suggest rationally designed combination therapies appropriate for disease subtypes.. |
| 2. | Takuji Yamauchi, Kohta Miyawaki, Yuichiro Semba, Masatomo Takahashi, Yoshihiro Izumi, Jumpei Nogami, Fumihiko Nakao, Takeshi Sugio, Kensuke Sasaki, Luca Pinello, Daniel E Bauer, Takeshi Bamba, Koichi Akashi, Takahiro Maeda, Targeting leukemia-specific dependence on the de novo purine synthesis pathway, Leukemia, 10.1038/s41375-021-01369-0, 2021.08, Acute myeloid leukemia (AML) is a devastating disease, and clinical outcomes are still far from satisfactory. Here, to identify novel targets for AML therapy, we performed a genome-wide CRISPR/Cas9 screen using AML cell lines, followed by a second screen in vivo. We show that PAICS, an enzyme involved in de novo purine biosynthesis, is a potential target for AML therapy. AML cells expressing shRNA-PAICS exhibited a proliferative disadvantage, indicating a toxic effect of shRNA-PAICS. Treatment of human AML cells with a PAICS inhibitor suppressed their proliferation by inhibiting DNA synthesis and promoting apoptosis and had anti-leukemic effects in AML PDX models. Furthermore, CRISPR/Cas9 screens using AML cells in the presence of the inhibitor revealed genes mediating resistance or synthetic lethal to PAICS inhibition. Our findings identify PAICS as a novel therapeutic target for AML and further define components of de novo purine synthesis pathway and its downstream effectors essential for AML cell survival.. |
| 3. | Kiyoshi Yoshioka, Hiroshi Nagahisa, Fumihito Miura, Hiromitsu Araki, Yasutomi Kamei, Yasuo Kitajima, Daiki Seko, Jumpei Nogami, Yoshifumi Tsuchiya, Narihiro Okazaki, Akihiko Yonekura, Seigo Ohba, Yoshinori Sumita, Ko Chiba, Kosei Ito, Izumi Asahina, Yoshihiro Ogawa, Takashi Ito, Yasuyuki Ohkawa, Yusuke Ono, Hoxa10 mediates positional memory to govern stem cell function in adult skeletal muscle, Science Advances, 10.1126/sciadv.abd7924, 2021.06, Muscle stem cells (satellite cells) are distributed throughout the body and have heterogeneous properties among muscles. However, functional topographical genes in satellite cells of adult muscle remain unidentified. Here, we show that expression of Homeobox-A (Hox-A) cluster genes accompanied with DNA hypermethylation of the Hox-A locus was robustly maintained in both somite-derived muscles and their associated satellite cells in adult mice, which recapitulates their embryonic origin. Somite-derived satellite cells were clearly separated from cells derived from cranial mesoderm in Hoxa10 expression. Hoxa10 inactivation led to genomic instability and mitotic catastrophe in somite-derived satellite cells in mice and human. Satellite cell-specific Hoxa10 ablation in mice resulted in a decline in the regenerative ability of somite-derived muscles, which were unobserved in cranial mesoderm-derived muscles. Thus, our results show that Hox gene expression profiles instill the embryonic history in satellite cells as positional memory, potentially modulating region-specific pathophysiology in adult muscles.. |
| 4. | Marino Maemura, Hiroaki Taketsuru, Yuki Nakajima, Ruiqi Shao, Ayaka Kakihara, Jumpei Nogami, Yasuyuki Ohkawa, Yu-Ichi Tsukada, Totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage, Scientific Reports, 10.1038/s41598-021-90653-1, 2021.05, In multicellular organisms, oocytes and sperm undergo fusion during fertilization and the resulting zygote gives rise to a new individual. The ability of zygotes to produce a fully formed individual from a single cell when placed in a supportive environment is known as totipotency. Given that totipotent cells are the source of all multicellular organisms, a better understanding of totipotency may have a wide-ranging impact on biology. The precise delineation of totipotent cells in mammals has remained elusive, however, although zygotes and single blastomeres of embryos at the two-cell stage have been thought to be the only totipotent cells in mice. We now show that a single blastomere of two- or four-cell mouse embryos can give rise to a fertile adult when placed in a uterus, even though blastomere isolation disturbs the transcriptome of derived embryos. Single blastomeres isolated from embryos at the eight-cell or morula stages and cultured in vitro manifested pronounced defects in the formation of epiblast and primitive endoderm by the inner cell mass and in the development of blastocysts, respectively. Our results thus indicate that totipotency of mouse zygotes extends to single blastomeres of embryos at the four-cell stage.. |
| 5. | Sjoerd J D Tjalsma, Mayako Hori, Yuko Sat, Aurelie Bousard, Akito Ohi, Ana Cláudia Raposo, Julia Roensch, Agnes Le Saux, Jumpei Nogami, Kazumitsu Maehara, Tomoya Kujirai, Tetsuya Handa, Sandra Bagés-Arnal, Yasuyuki Ohkawa, Hitoshi Kurumizaka, Simão Teixeira da Rocha, Jan J Żylicz, Hiroshi Kimura, Edith Heard, H4K20me1 and H3K27me3 are concurrently loaded onto the inactive X chromosome but dispensable for inducing gene silencing, EMBO Reports, 10.15252/embr.202051989, 2021.03, During X chromosome inactivation (XCI), in female placental mammals, gene silencing is initiated by the Xist long non-coding RNA. Xist accumulation at the X leads to enrichment of specific chromatin marks, including PRC2-dependent H3K27me3 and SETD8-dependent H4K20me1. However, the dynamics of this process in relation to Xist RNA accumulation remains unknown as is the involvement of H4K20me1 in initiating gene silencing. To follow XCI dynamics in living cells, we developed a genetically encoded, H3K27me3-specific intracellular antibody or H3K27me3-mintbody. By combining live-cell imaging of H3K27me3, H4K20me1, the X chromosome and Xist RNA, with ChIP-seq analysis we uncover concurrent accumulation of both marks during XCI, albeit with distinct genomic distributions. Furthermore, using a Xist B and C repeat mutant, which still shows gene silencing on the X but not H3K27me3 deposition, we also find a complete lack of H4K20me1 enrichment. This demonstrates that H4K20me1 is dispensable for the initiation of gene silencing, although it may have a role in the chromatin compaction that characterises facultative heterochromatin.. |
| 6. | Kazuhito Gotoh, Yuya Kunisaki, Soichi Mizuguchi, Daiki Setoyama, Kentaro Hosokawa, Hisayuki Yao, Yuya Nakashima, Mikako Yagi, Takeshi Uchiumi, Yuichiro Semba, Jumpei Nogami, Koichi Akashi, Fumio Arai, Dongchon Kang, Mitochondrial Protein Synthesis Is Essential for Terminal Differentiation of CD45- TER119-Erythroid and Lymphoid Progenitors, iScience, 10.1016/j.isci.2020.101654, 2020.10, p32/C1qbp regulates mitochondrial protein synthesis and is essential for oxidative phosphorylation in mitochondria. Although dysfunction of p32/C1qbp impairs fetal development and immune responses, its role in hematopoietic differentiation remains unclear. Here, we found that mitochondrial dysfunction affected terminal differentiation of newly identified erythroid/B-lymphoid progenitors among CD45- Ter119- CD31- triple-negative cells (TNCs) in bone marrow. Hematopoietic cell-specific genetic deletion of p32/C1qbp (p32cKO) in mice caused anemia and B-lymphopenia without reduction of hematopoietic stem/progenitor cells. In addition, p32cKO mice were susceptible to hematopoietic stress with delayed recovery from anemia. p32/C1qbp-deficient CD51- TNCs exhibited impaired mitochondrial oxidation that consequently led to inactivation of mTORC1 signaling, which is essential for erythropoiesis. These findings uncover the importance of mitochondria, especially at the stage of TNCs during erythropoiesis, suggesting that dysregulation of mitochondrial protein synthesis is a cause of anemia and B-lymphopenia with an unknown pathology.. |
| 7. | Yuki Akieda, Shohei Ogamino, Hironobu Furuie, Shizuka Ishitani, Ryutaro Akiyoshi, Jumpei Nogami, Takamasa Masuda, Nobuyuki Shimizu, Yasuyuki Ohkawa, Tohru Ishitani, Cell competition corrects noisy Wnt morphogen gradients to achieve robust patterning in the zebrafish embryo, Nature communications, 10.1038/s41467-019-12609-4, 10, 1, 2019.12, [URL], Morphogen signalling forms an activity gradient and instructs cell identities in a signalling strength-dependent manner to pattern developing tissues. However, developing tissues also undergo dynamic morphogenesis, which may produce cells with unfit morphogen signalling and consequent noisy morphogen gradients. Here we show that a cell competition-related system corrects such noisy morphogen gradients. Zebrafish imaging analyses of the Wnt/β-catenin signalling gradient, which acts as a morphogen to establish embryonic anterior-posterior patterning, identify that unfit cells with abnormal Wnt/β-catenin activity spontaneously appear and produce noise in the gradient. Communication between unfit and neighbouring fit cells via cadherin proteins stimulates apoptosis of the unfit cells by activating Smad signalling and reactive oxygen species production. This unfit cell elimination is required for proper Wnt/β-catenin gradient formation and consequent anterior-posterior patterning. Because this gradient controls patterning not only in the embryo but also in adult tissues, this system may support tissue robustness and disease prevention.. |
| 8. | Mohamed Osama Ali Abdalla, Tatsuro Yamamoto, Kazumitsu Maehara, Jumpei Nogami, Yasuyuki Ohkawa, Hisashi Miura, Rawin Poonperm, Ichiro Hiratani, Hideki Nakayama, Mitsuyoshi Nakao, Noriko Saitoh, The Eleanor ncRNAs activate the topological domain of the ESR1 locus to balance against apoptosis, Nature communications, 10.1038/s41467-019-11378-4, 10, 1, 2019.12, [URL], MCF7 cells acquire estrogen-independent proliferation after long-term estrogen deprivation (LTED), which recapitulates endocrine therapy resistance. LTED cells can become primed for apoptosis, but the underlying mechanism is largely unknown. We previously reported that Eleanor non-coding RNAs (ncRNAs) upregulate the ESR1 gene in LTED cells. Here, we show that Eleanors delineate the topologically associating domain (TAD) of the ESR1 locus in the active nuclear compartment of LTED cells. The TAD interacts with another transcriptionally active TAD, which is 42.9 Mb away from ESR1 and contains a gene encoding the apoptotic transcription factor FOXO3. Inhibition of a promoter-associated Eleanor suppresses all genes inside the Eleanor TAD and the long-range interaction between the two TADs, but keeps FOXO3 active to facilitate apoptosis in LTED cells. These data indicate a role of ncRNAs in chromatin domain regulation, which may underlie the apoptosis-prone nature of therapy-resistant breast cancer cells and could be good therapeutic targets.. |
| 9. | Masahiro Oka, Sonoko Mura, Mayumi Otani, Yoichi Miyamoto, Jumpei Nogami, Kazumitsu Maehara, Akihito Harada, Taro Tachibana, Yoshihiro Yoneda, Yasuyuki Ohkawa, Chromatin-bound CRM1 recruits SET-Nup214 and NPM1c onto HOX clusters causing aberrant HOX expression in leukemia cells, eLife, 10.7554/eLife.46667, 8, 2019.11, [URL], We previously demonstrated that CRM1, a major nuclear export factor, accumulates at Hox cluster regions to recruit nucleoporin-fusion protein Nup98HoxA9, resulting in robust activation of Hox genes (Oka et al., 2016). However, whether this phenomenon is general to other leukemogenic proteins remains unknown. Here, we show that two other leukemogenic proteins, nucleoporin-fusion SET-Nup214 and the NPM1 mutant, NPM1c, which contains a nuclear export signal (NES) at its C-terminus and is one of the most frequent mutations in acute myeloid leukemia, are recruited to the HOX cluster region via chromatin-bound CRM1, leading to HOX gene activation in human leukemia cells. Furthermore, we demonstrate that this mechanism is highly sensitive to a CRM1 inhibitor in leukemia cell line. Together, these findings indicate that CRM1 acts as a key molecule that connects leukemogenic proteins to aberrant HOX gene regulation either via nucleoporin-CRM1 interaction (for SET-Nup214) or NES-CRM1 interaction (for NPM1c).. |
| 10. | Hanna Witwicka, Jumpei Nogami, Sabriya A. Syed, Kazumitsu Maehara, Teresita Padilla-Benavides, Yasuyuki Ohkawa, Anthony N. Imbalzano, Calcineurin broadly regulates the initiation of skeletal muscle-specific gene expression by binding target promoters and facilitating the interaction of the SWI/SNF chromatin remodeling enzyme, Molecular and cellular biology, 10.1128/MCB.00063-19, 39, 19, 2019.10, [URL], Calcineurin (Cn) is a calcium-activated serine/threonine protein phosphatase that is broadly implicated in diverse cellular processes, including the regulation of gene expression. During skeletal muscle differentiation, Cn activates the nuclear factor of activated T-cell (NFAT) transcription factor but also promotes differentiation by counteracting the negative influences of protein kinase C beta (PKCβ) via dephosphorylation and activation of Brg1, an enzymatic subunit of the mammalian SWI/SNF ATP-dependent chromatin remodeling enzyme. Here we identified four major temporal patterns of Cn-dependent gene expression in differentiating myoblasts and determined that Cn is broadly required for the activation of the myogenic gene expression program. Mechanistically, Cn promotes gene expression through direct binding to myogenic promoter sequences and facilitating the binding of Brg1, other SWI/SNF subunit proteins, and MyoD, a critical lineage determinant for skeletal muscle differentiation. We conclude that the Cn phosphatase directly impacts the expression of myogenic genes by promoting ATP-dependent chromatin remodeling and formation of transcription-competent promoters.. |
| 11. | Shoko Sato, Yasuhiro Arimura, Tomoya Kujirai, Akihito Harada, Kazumitsu Maehara, Jumpei Nogami, Yasuyuki Ohkawa, Hitoshi Kurumizaka, Biochemical analysis of nucleosome targeting by Tn5 transposase, Open Biology, 10.1098/rsob.190116, 9, 8, 2019.08, [URL], Tn5 transposase is a bacterial enzyme that integrates a DNA fragment into genomic DNA, and is used as a tool for detecting nucleosome-free regions of genomic DNA in eukaryotes. However, in chromatin, the DNA targeting by Tn5 transposase has remained unclear. In the present study, we reconstituted well-positioned 601 dinucleosomes, in which two nucleosomes are connected with a linker DNA, and studied the DNA integration sites in the dinucleosomes by Tn5 transposase in vitro. We found that Tn5 transposase preferentially targets near the entry–exit DNA regions within the nucleosome. Tn5 transposase minimally cleaved the dinucleosome without a linker DNA, indicating that the linker DNA between two nucleosomes is important for the Tn5 transposase activity. In the presence of a 30 base-pair linker DNA, Tn5 transposase targets the middle of the linker DNA, in addition to the entry–exit sites of the nucleosome. Intriguingly, this Tn5-targeting characteristic is conserved in a dinucleosome substrate with a different DNA sequence from the 601 sequence. Therefore, the Tn5-targeting preference in the nucleosomal templates reported here provides important information for the interpretation of Tn5 transposase-based genomics methods, such as ATAC-seq.. |
| 12. | Yu Taro Noguchi, Miki Nakamura, Nobumasa Hino, Jumpei Nogami, Sayaka Tsuji, Takahiko Sato, Lidan Zhang, Kazutake Tsujikawa, Toru Tanaka, Kohei Izawa, Yoshiaki Okada, Takefumi Doi, Hiroki Kokubo, Akihito Harada, Akiyoshi Uezumi, Manfred Gessler, Yasuyuki Ohkawa, So Ichiro Fukada, Cell-autonomous and redundant roles of Hey1 and HeyL in muscle stem cells HeyL requires HeS1 to bind diverse DNA sites, Development (Cambridge), 10.1242/dev.163618, 146, 4, 2019.02, [URL], The undifferentiated state of muscle stem (satellite) cells (MuSCs) is maintained by the canonical Notch pathway. Although three bHLH transcriptional factors, Hey1, HeyL and Hes1, are considered to be potential effectors of the Notch pathway exerting anti-myogenic effects, neither HeyL nor Hes1 inhibits myogenic differentiation of myogenic cell lines. Furthermore, whether these factors work redundantly or cooperatively is unknown. Here, we showed cell-autonomous functions of Hey1 and HeyL in MuSCs using conditional and genetic null mice. Analysis of cultured MuSCs revealed anti-myogenic activity of both HeyL and Hes1. We found that HeyL forms heterodimeric complexes with Hes1 in living cells. Moreover, our ChIP-seq experiments demonstrated that, compared with HeyL alone, the HeyL-Hes1 heterodimer binds with high affinity to specific sites in the chromatin, including the binding sites of Hey1. Finally, analyses of myogenin promoter activity showed that HeyL and Hes1 act synergistically to suppress myogenic differentiation. Collectively, these results suggest that HeyL and Hey1 function redundantly in MuSCs, and that HeyL requires Hes1 for effective DNA binding and biological activity.. |
| 13. | Kazu Kobayakawa, Kyleigh Alexis DePetro, Hui Zhong, Bau Pham, Masamitsu Hara, Akihito Harada, Jumpei Nogami, Yasuyuki Ohkawa, V. Reggie Edgerton, Locomotor Training Increases Synaptic Structure With High NGL-2 Expression After Spinal Cord Hemisection, Neurorehabilitation and Neural Repair, 10.1177/1545968319829456, 2019.01, [URL], Background. We previously demonstrated that step training leads to reorganization of neuronal networks in the lumbar spinal cord of rodents after a hemisection (HX) injury and step training, including increases excitability of spinally evoked potentials in hindlimb motor neurons. Methods. In this study, we investigated changes in RNA expression and synapse number using RNA-Seq and immunohistochemistry of the lumbar spinal cord 23 days after a mid-thoracic HX in rats with and without post-HX step training. Results. Gene Ontology (GO) term clustering demonstrated that expression levels of 36 synapse-related genes were increased in trained compared with nontrained rats. Many synaptic genes were upregulated in trained rats, but Lrrc4 (coding NGL-2) was the most highly expressed in the lumbar spinal cord caudal to the HX lesion. Trained rats also had a higher number of NGL-2/synaptophysin synaptic puncta in the lumbar ventral horn. Conclusions. Our findings demonstrate clear activity-dependent regulation of synapse-related gene expression post-HX. This effect is consistent with the concept that activity-dependent phenomena can provide a mechanistic drive for epigenetic neuronal group selection in the shaping of the reorganization of synaptic networks to learn the locomotion task being trained after spinal cord injury.. |
| 14. | Akihito Harada, Kazumitsu Maehara, Yusuke Ono, Hiroyuki Taguchi, Kiyoshi Yoshioka, Yasuo Kitajima, Yan Xie, Yuko Sato, Takeshi Iwasaki, Jumpei Nogami, Seiji Okada, Tetsuro Komatsu, Yuichiro Semba, Tatsuya Takemoto, Hiroshi Kimura, Hitoshi Kurumizaka, Yasuyuki Ohkawa, Histone H3.3 sub-variant H3mm7 is required for normal skeletal muscle regeneration, Nature Communications, 10.1038/s41467-018-03845-1, 9, 1, 2018.12, [URL], Regulation of gene expression requires selective incorporation of histone H3 variant H3.3 into chromatin. Histone H3.3 has several subsidiary variants but their functions are unclear. Here we characterize the function of histone H3.3 sub-variant, H3mm7, which is expressed in skeletal muscle satellite cells. H3mm7 knockout mice demonstrate an essential role of H3mm7 in skeletal muscle regeneration. Chromatin analysis reveals that H3mm7 facilitates transcription by forming an open chromatin structure around promoter regions including those of myogenic genes. The crystal structure of the nucleosome containing H3mm7 reveals that, unlike the S57 residue of other H3 proteins, the H3mm7-specific A57 residue cannot form a hydrogen bond with the R40 residue of the cognate H4 molecule. Consequently, the H3mm7 nucleosome is unstable in vitro and exhibited higher mobility in vivo compared with the H3.3 nucleosome. We conclude that the unstable H3mm7 nucleosome may be required for proper skeletal muscle differentiation.. |
| 15. | Teppei Noda, Steven J. Meas, Jumpei Nogami, Yutaka Amemiya, Ryutaro Uchi, Yasuyuki Ohkawa, Koji Nishimura, Alain Dabdoub, Direct reprogramming of spiral ganglion non-neuronal cells into neurons Toward ameliorating sensorineural hearing loss by gene therapy, Frontiers in Cell and Developmental Biology, 10.3389/fcell.2018.00016, 6, FEB, 2018.02, [URL], Primary auditory neurons (PANs) play a critical role in hearing by transmitting sound information from the inner ear to the brain. Their progressive degeneration is associated with excessive noise, disease and aging. The loss of PANs leads to permanent hearing impairment since they are incapable of regenerating. Spiral ganglion non-neuronal cells (SGNNCs), comprised mainly of glia, are resident within the modiolus and continue to survive after PAN loss. These attributes make SGNNCs an excellent target for replacing damaged PANs through cellular reprogramming. We used the neurogenic pioneer transcription factor Ascl1 and the auditory neuron differentiation factor NeuroD1 to reprogram SGNNCs into induced neurons (iNs). The overexpression of both Ascl1 and NeuroD1 in vitro generated iNs at high efficiency. Transcriptome analyses revealed that iNs displayed a transcriptome profile resembling that of endogenous PANs, including expression of several key markers of neuronal identity: Tubb3, Map2, Prph, Snap25, and Prox1. Pathway analyses indicated that essential pathways in neuronal growth and maturation were activated in cells upon neuronal induction. Furthermore, iNs extended projections toward cochlear hair cells and cochlear nucleus neurons when cultured with each respective tissue. Taken together, our study demonstrates that PAN-like neurons can be generated from endogenous SGNNCs. This work suggests that gene therapy can be a viable strategy to treat sensorineural hearing loss caused by degeneration of PANs.. |
| 16. | Akihito Harada, Kazumitsu Maehara, Tetsuya Handa, Yasuhiro Arimura, Jumpei Nogami, Yoko Hayashi-Takanaka, Katsuhiko Shirahige, Hitoshi Kurumizaka, Hiroshi Kimura, Yasuyuki Ohkawa, A chromatin integration labelling method enables epigenomic profiling with lower input, Nature Cell Biology, 10.1038/s41556-018-0248-3, 2018.01, [URL], Chromatin plays a crucial role in gene regulation, and chromatin immunoprecipitation followed by sequencing (ChIP–seq) has been the standard technique for examining protein–DNA interactions across the whole genome. However, it is difficult to obtain epigenomic information from limited numbers of cells by ChIP–seq because of sample loss during chromatin preparation and inefficient immunoprecipitation. In this study, we established an immunoprecipitation-free epigenomic profiling method named chromatin integration labelling (ChIL), which enables the amplification of genomic sequences closely associated with the target molecules before cell lysis. Using ChIL followed by sequencing (ChIL–seq), we reliably detected the distributions of histone modifications and DNA-binding factors in 100–1,000 cells. In addition, ChIL–seq successfully detected genomic regions associated with histone marks at the single-cell level. Thus, ChIL–seq offers an alternative method to ChIP–seq for epigenomic profiling using small numbers of cells, in particular, those attached to culture plates and after immunofluorescence.. |
| 17. | Di Luo, Daiki Kato, Jumpei Nogami, Yasuyuki Ohkawa, Hitoshi Kurumizaka, Hidetoshi Kono, MNase, as a probe to study the sequence-dependent site exposures in the +1 nucleosomes of yeast, Nucleic Acids Research, 10.1093/nar/gky502, 46, 14, 7124-7137, 2018.01, [URL], The first nucleosomes in the downstream of transcription starting sites are called +1 nucleosomes, which are expected to be readily unwrapped for DNA transcription. To investigate DNA accessibility in +1 nucleosomes, MNase-seq experiments were carried out with 20 reconstituted +1 nucleosomes of budding yeast. Although MNase has been known for its sequence preference in DNA digestions, we confirmed that this sequence preference is overwhelmed by DNA accessibility by identifying the sequence-driven and accessibility-driven cleavages. Specifically, we find that sequences favoured by MNase at the end regions such as TA dinucleotide are prohibited from cleavage at the internal sites in the early stage of digestion. Nevertheless, sequences less favoured by MNase at the end regions such as AA/TT dinucleotide are predominantly cleaved at the internal sites in the early stage of digestion. Since AA/TT is known as a rigid dinucleotide step resistant to DNA bending, these internal cleavages reflect the local site exposures induced by DNA mechanics. As the DNA entry site of +1 nucleosomes in yeast is found AA/TT-rich, this sequence element may play a role in gene activation by reducing DNA-histone affinities along the direction of DNA transcription.. |
| 18. | Yuichiro Semba, Akihito Harada, Kazumitsu Maehara, Shinya Oki, Chikara Meno, Jun Ueda, Kazuo Yamagata, Atsushi Suzuki, Mitsuho Onimaru, Jumpei Nogami, Seiji Okada, Koichi Akashi, Yasuyuki Ohkawa, Chd2 regulates chromatin for proper gene expression toward differentiation in mouse embryonic stem cells, Nucleic Acids Research, 10.1093/nar/gkx475, 45, 15, 8758-8772, 2017.09, [URL], Chromatin reorganization is necessary for pluripotent stem cells, including embryonic stem cells (ESCs), to acquire lineage potential. However, it remains unclear how ESCs maintain their characteristic chromatin state for appropriate gene expression upon differentiation. Here, we demonstrate that chromodomain helicase DNA-binding domain 2 (Chd2) is required to maintain the differentiation potential of mouse ESCs. Chd2-depleted ESCs showed suppressed expression of developmentally regulated genes upon differentiation and subsequent differentiation defects without affecting gene expression in the undifferentiated state. Furthermore, chromatin immunoprecipitation followed by sequencing revealed alterations in the nucleosome occupancy of the histone variant H3.3 for developmentally regulated genes in Chd2-depleted ESCs, which in turn led to elevated trimethylation of the histone H3 lysine 27. These results suggest that Chd2 is essential in preventing suppressive chromatin formation for developmentally regulated genes and determines subsequent effects on developmental processes in the undifferentiated state.. |
| 19. | Hiroyuki Taguchi, Yan Xie, Naoki Horikoshi, Kazumitsu Maehara, Akihito Harada, Jumpei Nogami, Koichi Sato, Yasuhiro Arimura, Akihisa Osakabe, Tomoya Kujirai, Takeshi Iwasaki, Yuichiro Semba, Taro Tachibana, Hiroshi Kimura, Yasuyuki Ohkawa, Hitoshi Kurumizaka, Crystal Structure and Characterization of Novel Human Histone H3 Variants, H3.6, H3.7, and H3.8, Biochemistry, 10.1021/acs.biochem.6b01098, 56, 16, 2184-2196, 2017.04, [URL], Non-allelic histone variants are considered as epigenetic factors that regulate genomic DNA functions in eukaryotic chromosomes. In this study, we identified three new human histone H3 variants (named H3.6, H3.7, and H3.8), which were previously annotated as pseudogenes. H3.6 and H3.8 conserve the H3.3-specific amino acid residues, but H3.7 shares the specific amino acid residues with H3.1. We successfully reconstituted the nucleosome containing H3.6 in vitro and determined its crystal structure. In the H3.6 nucleosome, the H3.6-specific Val62 residue hydrophobically contacts the cognate H4 molecule, but its contact area is smaller than that of the corresponding H3.3 Ile62 residue. The thermal stability assay revealed that the H3.6 nucleosome is substantially unstable, as compared to the H3.3 nucleosome. Interestingly, mutational analysis demonstrated that the H3.6 Val62 residue is fully responsible for the H3.6 nucleosome instability, probably because of the weakened hydrophobic interaction with H4. We also reconstituted the nucleosome containing H3.8, but its thermal stability was quite low. In contrast, purified H3.7 failed to form nucleosomes in vitro. The identification and characterization of these novel human histone H3 variants provide important new insights into understanding the epigenetic regulation of the human genome.. |
| 20. | Daiki Kato, Akihisa Osakabe, Yasuhiro Arimura, Yuka Mizukami, Naoki Horikoshi, Kazumi Saikusa, Satoko Akashi, Yoshifumi Nishimura, Sam Yong Park, Jumpei Nogami, Kazumitsu Maehara, Yasuyuki Ohkawa, Atsushi Matsumoto, Hidetoshi Kono, Rintaro Inoue, Masaaki Sugiyama, Hitoshi Kurumizaka, Crystal structure of the overlapping dinucleosome composed of hexasome and octasome, Science, 10.1126/science.aak9867, 356, 6334, 205-208, 2017.04, [URL], Nucleosomes are dynamic entities that are repositioned along DNA by chromatin remodeling processes. A nucleosome repositioned by the switch-sucrose nonfermentable (SWI/SNF) remodeler collides with a neighbor and forms the intermediate "overlapping dinucleosome." Here, we report the crystal structure of the overlapping dinucleosome, in which two nucleosomes are associated, at 3.14-angstrom resolution. In the overlapping dinucleosome structure, the unusual "hexasome" nucleosome, composed of the histone hexamer lacking one H2A-H2B dimer from the conventional histone octamer, contacts the canonical "octasome" nucleosome, and they intimately associate. Consequently, about 250 base pairs of DNA are left-handedly wrapped in three turns, without a linker DNA segment between the hexasome and octasome moieties. The overlapping dinucleosome structure may provide important information to understand how nucleosome repositioning occurs during the chromatin remodeling process.. |
| 21. | Tomohumi Nakamura, Kouichi Murakami, Haruto Tada, Yoshihiko Uehara, Jumpei Nogami, Kazumitsu Maehara, Yasuyuki Ohkawa, Hisato Saitoh, Hideo Nishitani, Tetsuya Ono, Ryotaro Nishi, Masayuki Yokoi, Wataru Sakai, Kaoru Sugasawa, Thymine DNA glycosylase modulates DNA damage response and gene expression by base excision repair-dependent and independent mechanisms, Genes to Cells, 10.1111/gtc.12481, 22, 4, 392-405, 2017.04, [URL], Thymine DNA glycosylase (TDG) is a base excision repair (BER) enzyme, which is implicated in correction of deamination-induced DNA mismatches, the DNA demethylation process and regulation of gene expression. Because of these pivotal roles associated, it is crucial to elucidate how the TDG functions are appropriately regulated in vivo. Here, we present evidence that the TDG protein undergoes degradation upon various types of DNA damage, including ultraviolet light (UV). The UV-induced degradation of TDG was dependent on proficiency in nucleotide excision repair and on CRL4CDT 2-mediated ubiquitination that requires a physical interaction between TDG and DNA polymerase clamp PCNA. Using the Tdg-deficient mouse embryonic fibroblasts, we found that ectopic expression of TDG compromised cellular survival after UV irradiation and repair of UV-induced DNA lesions. These negative effects on cellular UV responses were alleviated by introducing mutations in TDG that impaired its BER function. The expression of TDG induced a large-scale alteration in the gene expression profile independently of its DNA glycosylase activity, whereas a subset of genes was affected by the catalytic activity of TDG. Our results indicate the presence of BER-dependent and BER-independent functions of TDG, which are involved in regulation of cellular DNA damage responses and gene expression patterns.. |
| 22. | Jun Ueda, Akihito Harada, Takashi Urahama, Shinichi Machida, Kazumitsu Maehara, Masashi Hada, Yoshinori Makino, Jumpei Nogami, Naoki Horikoshi, Akihisa Osakabe, Hiroyuki Taguchi, Hiroki Tanaka, Hiroaki Tachiwana, Tatsuma Yao, Minami Yamada, Takashi Iwamoto, Ayako Isotani, Masahito Ikawa, Taro Tachibana, Yuki Okada, Hiroshi Kimura, Yasuyuki Ohkawa, Hitoshi Kurumizaka, Kazuo Yamagata, Testis-Specific Histone Variant H3t Gene Is Essential for Entry into Spermatogenesis, Cell Reports, 10.1016/j.celrep.2016.12.065, 18, 3, 593-600, 2017.01, [URL], Cellular differentiation is associated with dynamic chromatin remodeling in establishing a cell-type-specific epigenomic landscape. Here, we find that mouse testis-specific and replication-dependent histone H3 variant H3t is essential for very early stages of spermatogenesis. H3t gene deficiency leads to azoospermia because of the loss of haploid germ cells. When differentiating spermatogonia emerge in normal spermatogenesis, H3t appears and replaces the canonical H3 proteins. Structural and biochemical analyses reveal that H3t-containing nucleosomes are more flexible than the canonical nucleosomes. Thus, by incorporating H3t into the genome during spermatogonial differentiation, male germ cells are able to enter meiosis and beyond.. |
| 23. | Kensuke Kudou, Tetsuro Komatsu, Jumpei Nogami, Kazumitsu Maehara, Akihito Harada, Hiroshi Saeki, Eiji Oki, Yoshihiko Maehara, Yasuyuki Ohkawa, The requirement of Mettl3-promoted MyoD mRNA maintenance in proliferative myoblasts for skeletal muscle differentiation, Open Biology, 10.1098/rsob.170119, 7, 9, 2017.01, [URL], Myogenic progenitor/stem cells retain their skeletal muscle differentiation potential by maintaining myogenic transcription factors such as MyoD. However, the mechanism of how MyoD expression is maintained in proliferative progenitor cells has not been elucidated. Here, we found that MyoD expression was reduced at the mRNA level by cell cycle arrest in S and G2 phases, which in turn led to the absence of skeletal muscle differentiation. The reduction of MyoD mRNA was correlated with the reduced expression of factors regulating RNA metabolism, including methyltransferase like 3 (Mettl3), which induces N6-methyladenosine (m6A) modifications of RNA. Knockdown of Mettl3 revealed that MyoD RNA was specifically downregulated and that this was caused by a decrease in processed, but not unprocessed, mRNA. Potential m6A modification sites were profiled by m6A sequencing and identified within the 50 untranslated region (UTR) of MyoD mRNA. Deletion of the 50 UTR revealed that it has a role in MyoD mRNA processing. These data showed that Mettl3 is required for MyoD mRNA expression in proliferative myoblasts.. |
本データベースの内容を無断転載することを禁止します。