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Satou-Kobayashi Y, Takahashi S, Haramoto Y, Asashima M, Taira M. Zbtb11 interacts with Otx2 and patterns the anterior neuroectoderm in Xenopus. PLoS One 2024; 19:e0293852. [PMID: 39083515 PMCID: PMC11290676 DOI: 10.1371/journal.pone.0293852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 06/19/2024] [Indexed: 08/02/2024] Open
Abstract
The zinc finger and BTB domain-containing 11 gene (zbtb11) is expressed in the Xenopus anterior neuroectoderm, but the molecular nature of the Zbtb11 protein during embryonic development remains to be elucidated. Here, we show the role of Zbtb11 in anterior patterning of the neuroectoderm and the cooperative action with the transcription factor Otx2. Both overexpression and knockdown of zbtb11 caused similar phenotypes: expanded expression of the posterior gene gbx2 in the neural plate, and later microcephaly with reduced eyes, suggesting that a proper level of zbtb11 expression is necessary for normal patterning of the neuroectoderm, including eye formation. Co-immunoprecipitation assays showed that Zbtb11 formed a complex with itself and with a phosphomimetic and repressive form of Otx2, suggesting that Zbtb11 forms a dimer or oligomer and interacts with Otx2 in a phosphorylation-dependent manner. Reporter analysis further showed that Zbtb11 enhanced the activity of the phosphomimetic Otx2 to repress a silencer element of the posterior gene meis3. These data suggest that Zbtb11 coordinates with phosphorylated Otx2 to specify the anterior neuroectoderm by repressing posterior genes.
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Affiliation(s)
- Yumeko Satou-Kobayashi
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
- Advanced Comprehensive Research Organization, Teikyo University, Tokyo, Japan
| | - Shuji Takahashi
- Amphibian Research Center, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Yoshikazu Haramoto
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan
- Department of Agri-Production Sciences, College of Agriculture, Tamagawa University, Tokyo, Japan
| | - Makoto Asashima
- Advanced Comprehensive Research Organization, Teikyo University, Tokyo, Japan
| | - Masanori Taira
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan
- Faculty of Science and Engineering, Chuo University, Tokyo, Japan
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Brislinger-Engelhardt MM, Lorenz F, Haas M, Bowden S, Tasca A, Kreutz C, Walentek P. Temporal Notch signaling regulates mucociliary cell fates through Hes-mediated competitive de-repression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528675. [PMID: 36824900 PMCID: PMC9949065 DOI: 10.1101/2023.02.15.528675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Tissue functions are determined by the types and ratios of cells present, but little is known about self-organizing principles establishing correct cell type compositions. Mucociliary airway clearance relies on the correct balance between secretory and ciliated cells, which is regulated by Notch signaling across mucociliary systems. Using the airway-like Xenopus epidermis, we investigate how cell fates depend on signaling, how signaling levels are controlled, and how Hes transcription factors regulate cell fates. We show that four mucociliary cell types each require different Notch levels and that their specification is initiated sequentially by a temporal Notch gradient. We describe a novel role for Foxi1 in the generation of Delta-expressing multipotent progenitors through Hes7.1. Hes7.1 is a weak repressor of mucociliary genes and overcomes maternal repression by the strong repressor Hes2 to initiate mucociliary development. Increasing Notch signaling then inhibits Hes7.1 and activates first Hes4, then Hes5.10, which selectively repress cell fates. We have uncovered a self-organizing mechanism of mucociliary cell type composition by competitive de-repression of cell fates by a set of differentially acting repressors. Furthermore, we present an in silico model of this process with predictive abilities.
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Affiliation(s)
- Magdalena Maria Brislinger-Engelhardt
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- SGBM Spemann Graduate School for Biology and Medicine, University of Freiburg, Albertstrasse 19A, 79104 Freiburg, Germany
| | - Fabian Lorenz
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- IMBI Institute of Medical Biometry and Statistics, Institute of Medicine and Medical Center Freiburg, Stefan-Meier Strasse 26, 79104 Freiburg, Germany
| | - Maximilian Haas
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
- SGBM Spemann Graduate School for Biology and Medicine, University of Freiburg, Albertstrasse 19A, 79104 Freiburg, Germany
| | - Sarah Bowden
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- IMPRS-IEM International Max Planck Research School of Immunobiology, Epigenetics and Metabolism, Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108 Freiburg, Germany
| | - Alexia Tasca
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
| | - Clemens Kreutz
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- IMBI Institute of Medical Biometry and Statistics, Institute of Medicine and Medical Center Freiburg, Stefan-Meier Strasse 26, 79104 Freiburg, Germany
| | - Peter Walentek
- Department of Medicine IV, University Freiburg Medical Center, Faculty of Medicine, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
- SGBM Spemann Graduate School for Biology and Medicine, University of Freiburg, Albertstrasse 19A, 79104 Freiburg, Germany
- IMPRS-IEM International Max Planck Research School of Immunobiology, Epigenetics and Metabolism, Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108 Freiburg, Germany
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Hidalgo-Sánchez M, Andreu-Cervera A, Villa-Carballar S, Echevarria D. An Update on the Molecular Mechanism of the Vertebrate Isthmic Organizer Development in the Context of the Neuromeric Model. Front Neuroanat 2022; 16:826976. [PMID: 35401126 PMCID: PMC8987131 DOI: 10.3389/fnana.2022.826976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/28/2022] [Indexed: 11/13/2022] Open
Abstract
A crucial event during the development of the central nervous system (CNS) is the early subdivision of the neural tube along its anterior-to-posterior axis to form neuromeres, morphogenetic units separated by transversal constrictions and programed for particular genetic cascades. The narrower portions observed in the developing neural tube are responsible for relevant cellular and molecular processes, such as clonal restrictions, expression of specific regulatory genes, and differential fate specification, as well as inductive activities. In this developmental context, the gradual formation of the midbrain-hindbrain (MH) constriction has been an excellent model to study the specification of two major subdivisions of the CNS containing the mesencephalic and isthmo-cerebellar primordia. This MH boundary is coincident with the common Otx2-(midbrain)/Gbx2-(hindbrain) expressing border. The early interactions between these two pre-specified areas confer positional identities and induce the generation of specific diffusible morphogenes at this interface, in particular FGF8 and WNT1. These signaling pathways are responsible for the gradual histogenetic specifications and cellular identity acquisitions with in the MH domain. This review is focused on the cellular and molecular mechanisms involved in the specification of the midbrain/hindbrain territory and the formation of the isthmic organizer. Emphasis will be placed on the chick/quail chimeric experiments leading to the acquisition of the first fate mapping and experimental data to, in this way, better understand pioneering morphological studies and innovative gain/loss-of-function analysis.
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Affiliation(s)
- Matías Hidalgo-Sánchez
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
- *Correspondence: Matías Hidalgo-Sánchez Diego Echevarria
| | - Abraham Andreu-Cervera
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
| | - Sergio Villa-Carballar
- Departamento de Biología Celular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain
| | - Diego Echevarria
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Alicante, Spain
- *Correspondence: Matías Hidalgo-Sánchez Diego Echevarria
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Kuretani A, Yamamoto T, Taira M, Michiue T. Evolution of hes gene family in vertebrates: the hes5 cluster genes have specifically increased in frogs. BMC Ecol Evol 2021; 21:147. [PMID: 34325655 PMCID: PMC8320183 DOI: 10.1186/s12862-021-01879-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 07/08/2021] [Indexed: 11/29/2022] Open
Abstract
Background hes genes are chordate homologs of Drosophila genes, hairy and enhancer of split, which encode a basic helix-loop-helix (bHLH) transcriptional repressor with a WRPW motif. Various developmental functions of hes genes, including early embryogenesis and neurogenesis, have been elucidated in vertebrates. However, their orthologous relationships remain unclear partly because of less conservation of relatively short amino acid sequences, the fact that the genome was not analyzed as it is today, and species-specific genome duplication. This results in complicated gene names in vertebrates, which are not consistent in orthologs. We previously revealed that Xenopus frogs have two clusters of hes5, named “the hes5.1 cluster” and “the hes5.3 cluster”, but the origin and the conservation have not yet been revealed. Results Here, we elucidated the orthologous and paralogous relationships of all hes genes of human, mouse, chicken, gecko, zebrafish, medaka, coelacanth, spotted gar, elephant shark and three species of frogs, Xenopus tropicalis (X. tropicalis), X. laevis, Nanorana parkeri, by phylogenetic and synteny analyses. Any duplicated hes5 were not found in mammals, whereas hes5 clusters in teleost were conserved although not as many genes as the three frog species. In addition, hes5 cluster-like structure was found in the elephant shark genome, but not found in cyclostomata. Conclusion These data suggest that the hes5 cluster existed in the gnathostome ancestor but became a single gene in mammals. The number of hes5 cluster genes were specifically large in frogs. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01879-6.
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Affiliation(s)
- Aya Kuretani
- Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Takayoshi Yamamoto
- Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Masanori Taira
- Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.,Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo, 112-8551, Japan
| | - Tatsuo Michiue
- Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan. .,Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1, Komaba, Meguro-ku, Tokyo, 153-8902, Japan.
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Hes5.9 Coordinate FGF and Notch Signaling to Modulate Gastrulation via Regulating Cell Fate Specification and Cell Migration in Xenopus tropicalis. Genes (Basel) 2020; 11:genes11111363. [PMID: 33218193 PMCID: PMC7699193 DOI: 10.3390/genes11111363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/02/2020] [Accepted: 11/13/2020] [Indexed: 01/15/2023] Open
Abstract
Gastrulation drives the establishment of three germ layers and embryonic axes during frog embryonic development. Mesodermal cell fate specification and morphogenetic movements are vital factors coordinating gastrulation, which are regulated by numerous signaling pathways, such as the Wnt (Wingless/Integrated), Notch, and FGF (Fibroblast growth factor) pathways. However, the coordination of the Notch and FGF signaling pathways during gastrulation remains unclear. We identified a novel helix–loop–helix DNA binding domain gene (Hes5.9), which was regulated by the FGF and Notch signaling pathways during gastrulation. Furthermore, gain- and loss-of-function of Hes5.9 led to defective cell migration and disturbed the expression patterns of mesodermal and endodermal marker genes, thus interfering with gastrulation. Collectively, these results suggest that Hes5.9 plays a crucial role in cell fate decisions and cell migration during gastrulation, which is modulated by the FGF and Notch signaling pathways.
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Transcription Factors of the bHLH Family Delineate Vertebrate Landmarks in the Nervous System of a Simple Chordate. Genes (Basel) 2020; 11:genes11111262. [PMID: 33114624 PMCID: PMC7693978 DOI: 10.3390/genes11111262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 10/12/2020] [Indexed: 02/07/2023] Open
Abstract
Tunicates are marine invertebrates whose tadpole-like larvae feature a highly simplified version of the chordate body plan. Similar to their distant vertebrate relatives, tunicate larvae develop a regionalized central nervous system and form distinct neural structures, which include a rostral sensory vesicle, a motor ganglion, and a caudal nerve cord. The sensory vesicle contains a photoreceptive complex and a statocyst, and based on the comparable expression patterns of evolutionarily conserved marker genes, it is believed to include proto-hypothalamic and proto-retinal territories. The evolutionarily conserved molecular fingerprints of these landmarks of the vertebrate brain consist of genes encoding for different transcription factors, and of the gene batteries that they control, and include several members of the bHLH family. Here we review the complement of bHLH genes present in the streamlined genome of the tunicate Ciona robusta and their current classification, and summarize recent studies on proneural bHLH transcription factors and their expression territories. We discuss the possible roles of bHLH genes in establishing the molecular compartmentalization of the enticing nervous system of this unassuming chordate.
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7
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Watanabe M, Yasuoka Y, Mawaribuchi S, Kuretani A, Ito M, Kondo M, Ochi H, Ogino H, Fukui A, Taira M, Kinoshita T. Conservatism and variability of gene expression profiles among homeologous transcription factors in Xenopus laevis. Dev Biol 2017; 426:301-324. [DOI: 10.1016/j.ydbio.2016.09.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Revised: 07/27/2016] [Accepted: 09/19/2016] [Indexed: 12/11/2022]
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8
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Manojlovic Z, Earwood R, Kato A, Perez D, Cabrera OA, Didier R, Megraw TL, Stefanovic B, Kato Y. La-related protein 6 controls ciliated cell differentiation. Cilia 2017; 6:4. [PMID: 28344782 PMCID: PMC5364628 DOI: 10.1186/s13630-017-0047-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 02/16/2017] [Indexed: 01/07/2023] Open
Abstract
Background La-related protein 6 (LARP6) is an evolutionally conserved RNA-binding protein. Vertebrate LARP6 binds the 5′ stem-loop found in mRNAs encoding type I collagen to regulate their translation, but other target mRNAs and additional functions for LARP6 are unknown. The aim of this study was to elucidate an additional function of LARP6 and to evaluate the importance of its function during development. Methods To uncover the role of LARP6 in development, we utilized Morpholino Oligos to deplete LARP6 protein in Xenopus embryos. Then, embryonic phenotypes and ciliary structures of LAPR6 morphants were examined. To identify the molecular mechanism underlying ciliogenesis regulated by LARP6, we tested the expression level of cilia-related genes, which play important roles in ciliogenesis, by RT-PCR or whole mount in situ hybridization (WISH). Results We knocked down LARP6 in Xenopus embryos and found neural tube closure defects. LARP6 mutant, which compromises the collagen synthesis, could rescue these defects. Neural tube closure defects are coincident with lack of cilia, antenna-like cellular organelles with motility- or sensory-related functions, in the neural tube. The absence of cilia at the epidermis was also observed in LARP6 morphants, and this defect was due to the absence of basal bodies which are formed from centrioles and required for ciliary assembly. In the process of multi-ciliated cell (MCC) differentiation, mcidas, which activates the transcription of genes required for centriole formation during ciliogenesis, could partially restore MCCs in LARP6 morphants. In addition, LARP6 likely controls the expression of mcidas in a Notch-independent manner. Conclusions La-related protein 6 is involved in ciliated cell differentiation during development by controlling the expression of cilia-related genes including mcidas. This LARP6 function involves a mechanism that is distinct from its established role in binding to collagen mRNAs and regulating their translation. Electronic supplementary material The online version of this article (doi:10.1186/s13630-017-0047-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zarko Manojlovic
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA.,Department of Translational Genomics, Keck School of Medicine of University of Southern California, Los Angeles, CA 90089-9601 USA
| | - Ryan Earwood
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Akiko Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Diana Perez
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Oscar A Cabrera
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Ruth Didier
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
| | - Yoichi Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, 1115W. Call Street, Tallahassee, FL 32306-4300 USA
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Manojlovic Z, Earwood R, Kato A, Stefanovic B, Kato Y. RFX7 is required for the formation of cilia in the neural tube. Mech Dev 2014; 132:28-37. [PMID: 24530844 DOI: 10.1016/j.mod.2014.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 02/04/2014] [Indexed: 12/22/2022]
Abstract
Regulatory Factor X (RFX) transcription factors are important for development and are likely involved in the pathogenesis of serious human diseases including ciliopathies. While seven RFX genes have been identified in vertebrates and several RFX transcription factors have been reported to be regulators of ciliogenesis, the role of RFX7 in development including ciliogenesis is not known. Here we show that RFX7 in Xenopus laevis is expressed in the neural tube, eye, otic vesicles, and somites. Knockdown of RFX7 in Xenopus embryos resulted in a defect of ciliogenesis in the neural tube and failure of neural tube closure. RFX7 controlled the formation of cilia by regulating the expression of RFX4 gene, which has been reported to be required for ciliogenesis in the neural tube. Moreover, ectopic expression of Foxj1, which is a master regulator of motile cilia formation, suppressed the expression of RFX4 but not RFX7. Taken together, RFX7 plays an important role in the process of neural tube closure at the top of the molecular cascade which controls ciliogenesis in the neural tube.
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Affiliation(s)
- Zarko Manojlovic
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA
| | - Ryan Earwood
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA
| | - Akiko Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA
| | - Branko Stefanovic
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA.
| | - Yoichi Kato
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32306, USA.
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10
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A potential molecular pathogenesis of cardiac/laterality defects in Oculo-Facio-Cardio-Dental syndrome. Dev Biol 2014; 387:28-36. [PMID: 24440151 DOI: 10.1016/j.ydbio.2014.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/04/2014] [Accepted: 01/09/2014] [Indexed: 01/16/2023]
Abstract
Pitx2 is the last effector of the left-right (LR) cascade known to date and plays a crucial role in the patterning of LR asymmetry. In Xenopus embryos, the expression of Pitx2 gene in the left lateral plate mesoderm (LPM) is directly regulated by Xnr1 signaling, which is mediated by Smads and FoxH1. Previous studies suggest that the suppression of Pitx2 gene in the left LPM is a potential cause of cardiac/laterality defects in Oculo-Facio-Cardio-Dental (OFCD) syndrome, which is known to be caused by mutations in BCL6 co-repressor (BCOR) gene. Recently, our work has revealed that the BCL6/BCOR complex blocks Notch-dependent transcriptional activity to protect the expression of Pitx2 in the left LPM from the inhibitory activity of Notch signaling. These studies indicated that uncontrolled Notch activity in the left LPM caused by dysfunction of BCOR may result in cardiac/laterality defects of OFCD syndrome. However, this Notch-dependent inhibitory mechanism of Pitx2 gene transcription still remains unknown. Here we report that transcriptional repressor ESR1, which acts downstream of Notch signaling, inhibits the expression of Pitx2 gene by binding to a left side-specific enhancer (ASE) region in Pitx2 gene and recruiting histone deacetylase 1 (HDAC1) to this region. Once HDAC1 is tethered, histone acetyltransferase p300 is no longer recruited to the Xnr1-dependent transcriptional complex on the ASE region, leading to the suppression of Pitx2 gene in the left LPM. The study presented here uncovers the regulatory mechanism of Pitx2 gene transcription which may contribute to an understanding of pathogenesis of OFCD syndrome.
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11
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Xenopus Nkx6.1 and Nkx6.2 are required for mid-hindbrain boundary development. Dev Genes Evol 2013; 223:253-9. [PMID: 23423436 DOI: 10.1007/s00427-013-0437-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 02/05/2013] [Indexed: 01/25/2023]
Abstract
The mid-hindbrain boundary (MHB) organizer is among the best studied local organizers that patterns the midbrain and cerebellum in vertebrates and is established by a regulatory network of several transcription factors and signals, including Wnt signaling. In the present study, we found that Xenopus Nkx6.1 and Nkx6.2, two transcription factors of the Nkx homeobox family, are required for MHB formation. In Xenopus embryos, nkx6.1 and nkx6.2 are expressed in the MHB, and knockdown of either nkx6.1 or nkx6.2 by specific morpholinos disrupts the MHB expression of en2 as well as wnt1, a key regulator for vertebrate MHB formation. In the nkx6.1/nkx6.2 morphants, co-injection of wnt1 or dngsk3β mRNA, which activates Wnt signaling, rescues the expression of en2. Nkx6.1 and Nkx6.2 activate canonical Wnt signaling in reporter assays in both cultured mammalian cells and Xenopus embryos. An Nkx6.2 deletion construct, which inhibits the ability of wild type Nkx6.2 to activate Wnt signaling, also reduces the MHB expression of en2 in Xenopus embryos. These results suggest that Nkx6.1 and Nkx6.2 are involved in MHB formation in Xenopus embryos, likely by modulating wnt1 expression.
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Kiyota T, Kato A, Kato Y. Ets-1 regulates radial glia formation during vertebrate embryogenesis. Organogenesis 2012; 3:93-101. [PMID: 19279707 DOI: 10.4161/org.3.2.5171] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Accepted: 11/19/2007] [Indexed: 11/19/2022] Open
Abstract
Radial glia cells are the first distinguishable glial population derived from neural epithelial cells and serve as guides for migrating neurons and as neural progenitor cells in the developing brain. Despite their functional importance during neural development, the determination and differentiation of these cells remains poorly understood at the molecular level. Ets-1 and Ets-2, Ets (E26 transformation-specific) transcription factors, are vertebrate homologues of Drosophila pointed, which is expressed in a subset of glia cells and promotes different aspects of Drosophila glia cell differentiation. However, it remains unsolved that the function of Ets genes is conserved in vertebrate glia development. Here we report that Ets-1 but not Ets-2 is necessary for Xenopus radial glia formation and the activity of Ets-1 is sufficient for radial glia formation prior to neural tube closure. Furthermore, we show that Ras-MAPK (mitogen activated protein kinase) signaling, which acts as an upstream activator of Ets-1 in other biological processes, also regulates radial glia formation. A mutant form of Ets-1, which is not responsive to Ras-MAPK signaling, inhibits radial glia formation promoted by Ras-MAPK signaling. Together, our results show that Ets-1 activated by Ras-MAPK signaling promotes radial glia formation during Xenopus embryogenesis.
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Affiliation(s)
- Tomomi Kiyota
- Department of Biomedical Science; Florida State University College of Medicine; Tallahassee, Florida USA
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Hooker L, Smoczer C, KhosrowShahian F, Wolanski M, Crawford MJ. Microarray-based identification of Pitx3 targets during Xenopus embryogenesis. Dev Dyn 2012; 241:1487-505. [PMID: 22826267 DOI: 10.1002/dvdy.23836] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2012] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Unexpected phenotypes resulting from morpholino-mediated translational knockdown of Pitx3 in Xenopus laevis required further investigation regarding the genetic networks in which the gene might play a role. Microarray analysis was, therefore, used to assess global transcriptional changes downstream of Pitx3. RESULTS From the large data set generated, selected candidate genes were confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization. CONCLUSIONS We have identified four genes as likely direct targets of Pitx3 action: Pax6, β Crystallin-b1 (Crybb1), Hes7.1, and Hes4. Four others show equivocal promise worthy of consideration: Vent2, and Ripply2 (aka Ledgerline or Stripy), eFGF and RXRα. We also describe the expression pattern of additional and novel genes that are Pitx3-sensitive but that are unlikely to be direct targets.
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Affiliation(s)
- Lara Hooker
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
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Affiliation(s)
- Clemens Kiecker
- Medical Research Council (MRC) Center for Developmental Neurobiology, King's College, London SE1 1UL, United Kingdom; ,
| | - Andrew Lumsden
- Medical Research Council (MRC) Center for Developmental Neurobiology, King's College, London SE1 1UL, United Kingdom; ,
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15
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Sakano D, Kato A, Parikh N, McKnight K, Terry D, Stefanovic B, Kato Y. BCL6 canalizes Notch-dependent transcription, excluding Mastermind-like1 from selected target genes during left-right patterning. Dev Cell 2010; 18:450-62. [PMID: 20230751 DOI: 10.1016/j.devcel.2009.12.023] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 10/15/2009] [Accepted: 12/22/2009] [Indexed: 11/19/2022]
Abstract
Although the Notch signaling pathway is one of the most intensely studied intracellular signaling pathways, the mechanisms by which Notch signaling regulates transcription remain incompletely understood. Here, we report that B cell leukemia/lymphoma 6 (BCL6), a transcriptional repressor, is a Notch-associated factor. BCL6 is necessary to maintain the expression of Pitx2 in the left lateral plate mesoderm during the patterning of left-right asymmetry in Xenopus embryos. For this process, BCL6 forms a complex with BCL6 corepressor (BCoR) on the promoters of selected Notch target genes such as enhancer of split related 1. BCL6 also inhibits the transcription of these genes by competing for the Notch1 intracellular domain, preventing the coactivator Mastermind-like1 (MAM1) from binding. These results define a mechanism restricting Notch-activated transcription to cell-type-appropriate subsets of target genes, and elucidate its relevance in vivo during left-right asymmetric development.
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Affiliation(s)
- Daisuke Sakano
- Department of Biomedical Sciences, Florida State University, College of Medicine, Tallahassee, FL 32306, USA
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16
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Takada H, Kawana T, Ito Y, Kikuno RF, Mamada H, Araki T, Koga H, Asashima M, Taira M. The RNA-binding protein Mex3b has a fine-tuning system for mRNA regulation in early Xenopus development. Development 2009; 136:2413-22. [PMID: 19542354 DOI: 10.1242/dev.029165] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Post-transcriptional control by RNA-binding proteins is a precise way to assure appropriate levels of gene expression. Here, we identify a novel mRNA regulatory system involving Mex3b (RKHD3) and demonstrate its role in FGF signaling. mex3b mRNA has a 3' long conserved UTR, named 3'LCU, which contains multiple elements for both mRNA destabilization and translational enhancement. Notably, Mex3b promotes destabilization of its own mRNA by binding to the 3'LCU, thereby forming a negative autoregulatory loop. The combination of positive regulation and negative autoregulation constitutes a fine-tuning system for post-transcriptional control. In early embryogenesis, Mex3b is involved in anteroposterior patterning of the neural plate. Consistent with this, Mex3b can attenuate FGF signaling and destabilize mRNAs for the FGF signaling components Syndecan 2 and Ets1b through their 3' UTRs. These data suggest that the 3'LCU-mediated fine-tuning system determines the appropriate level of mex3b expression, which in turn contributes to neural patterning through regulating FGF signaling.
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Affiliation(s)
- Hitomi Takada
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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17
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Involvement of an inner nuclear membrane protein, Nemp1, in Xenopus neural development through an interaction with the chromatin protein BAF. Dev Biol 2009; 327:497-507. [PMID: 19167377 DOI: 10.1016/j.ydbio.2008.12.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 12/22/2008] [Accepted: 12/23/2008] [Indexed: 11/20/2022]
Abstract
To clarify the molecular mechanisms of neural development in vertebrates, we analyzed a novel gene, termed nemp1 (nuclear envelope integral membrane protein 1), which is expressed in the Xenopus anterior neuroectoderm at the neurula stage. Nemp1 has a putative signal peptide and five transmembrane domains, but does not have any other known domains. We show that Nemp1 is localized to the inner nuclear membrane (INM) with its evolutionarily conserved C-terminal region facing the nucleoplasm. Both overexpression and knockdown of Nemp1 in Xenopus embryos reduced the expression of early eye marker genes, rax, tbx3, and pax6, and later resulted mainly in severe eye defects at the tailbud stage. In contrast, the expression of a forebrain/midbrain marker, otx2, and a pan-neural marker, sox2, was largely unaffected. Deletion analysis of Nemp1 showed that nuclear envelope-localization of the C-terminal region is necessary for its eye-reducing activity. Furthermore, nemp1 is coexpressed with baf (barrier-to-autointegration factor) in the eye anlagen, and that Nemp1 interacts with BAF through the BAF-binding site in the C-terminal region and this site is required for Nemp1 activity. These data suggest that Nemp1 is involved in the expression of eye marker genes by functioning at the INM at least partly through BAF.
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18
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Nagatomo KI, Hashimoto C. Xenopus hairy2 functions in neural crest formation by maintaining cells in a mitotic and undifferentiated state. Dev Dyn 2007; 236:1475-83. [PMID: 17436284 DOI: 10.1002/dvdy.21152] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The neural crest is a population of mitotically active, multipotent progenitor cells that arise at the neural plate border. Neural crest progenitors must be maintained in a multipotent state until after neural tube closure. However, the molecular underpinnings of this process have yet to be fully elucidated. Here we show that the basic helix-loop-helix (bHLH) transcriptional repressor gene, Xenopus hairy2 (Xhairy2), is an essential early regulator of neural crest formation in Xenopus. During gastrulation, Xhairy2 is localized at the presumptive neural crest prior to the expression of such neural crest markers as Slug and FoxD3. Morpholino-mediated knockdown of Xhairy2 results in the repression of neural crest marker gene expression while inducing the ectopic expression of the cell cycle inhibitor p27(xic1) in the presumptive neural crest. We also found that ectopic p27(xic1) disturbs neural crest formation. Furthermore, the depletion of Xhairy2 leads to the apoptosis of mitotic cells. Our results suggest that Xhairy2 functions in neural crest specification by maintaining cells in the mitotic and undifferentiated state.
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Affiliation(s)
- Kan-Ichiro Nagatomo
- Department of Biology, Graduate School of Science, Osaka University, and JT Biohistory Research Hall, Osaka, Japan
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19
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Baek JH, Hatakeyama J, Sakamoto S, Ohtsuka T, Kageyama R. Persistent and high levels of Hes1 expression regulate boundary formation in the developing central nervous system. Development 2006; 133:2467-76. [PMID: 16728479 DOI: 10.1242/dev.02403] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The developing central nervous system is partitioned into compartments by boundary cells, which have different properties than compartment cells, such as forming neuron-free zones, proliferating more slowly and acting as organizing centers. We now report that in mice the bHLH factor Hes1 is persistently expressed at high levels by boundary cells but at variable levels by non-boundary cells. Expression levels of Hes1 display an inverse correlation to those of the proneural bHLH factor Mash1, suggesting that downregulation of Hes1 leads to upregulation of Mash1 in non-boundary regions,whereas persistent and high Hes1 expression constitutively represses Mash1 in boundary regions. In agreement with this notion, in the absence of Hes1 and its related genes Hes3 and Hes5, proneural bHLH genes are ectopically expressed in boundaries, resulting in ectopic neurogenesis and disruption of the organizing centers. Conversely, persistent Hes1 expression in neural progenitors prepared from compartment regions blocks neurogenesis and reduces cell proliferation rates. These results indicate that the mode of Hes1 expression is different between boundary and non-boundary cells, and that persistent and high levels of Hes1 expression constitutively repress proneural bHLH gene expression and reduce cell proliferation rates,thereby forming boundaries that act as the organizing centers.
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Affiliation(s)
- Joung Hee Baek
- Institute for Virus Research, Kyoto University, Shogoin-Kawahara, Kyoto 606-8507, Japan
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