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Jeon H, Jin S, Choe CP. inka1b expression in the head mesoderm is dispensable for facial cartilage development. Gene Expr Patterns 2022; 45:119262. [PMID: 35811016 DOI: 10.1016/j.gep.2022.119262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022]
Abstract
Inka box actin regulator 1 (Inka1) is a novel protein identified in Xenopus and is found in vertebrates. While Inka1 is required for facial skeletal development in Xenopus and zebrafish, it is dispensable in mice despite its conserved expression in the cranial neural crest, indicating that Inka1 function in facial skeletal development is not conserved among vertebrates. Zebrafish bears two paralogs of inka1 (inka1a and inka1b) in the genome, with the biological roles of inka1b barely known. Here, we analyzed the expression and function of inka1b during facial skeletal development in zebrafish. inka1b was expressed sequentially in the head mesoderm adjacent to the pharyngeal pouches essential for facial skeletal development at the stage of arch segmentation. However, a loss-of-function mutation in inka1b displayed normal head development, including the pouches and facial cartilages. The normal head of inka1b mutant fish was unlikely a result of the genetic redundancy of inka1b with inka1a, given the distinct expression of inka1a and inka1b in the cranial neural crest and head mesoderm, respectively, during craniofacial development. Our findings suggest that the inka1b expression in the head mesoderm might not be essential for head development in zebrafish.
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Affiliation(s)
- Haewon Jeon
- Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, South Korea
| | - Sil Jin
- Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, South Korea
| | - Chong Pyo Choe
- Division of Applied Life Science, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 52828, South Korea; Division of Life Science, Gyeongsang National University, Jinju, 52828, South Korea.
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2
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Kettler L, Sid H, Schaub C, Lischka K, Klinger R, Moser M, Schusser B, Luksch H. AP-2δ Expression Kinetics in Multimodal Networks in the Developing Chicken Midbrain. Front Neural Circuits 2021; 15:756184. [PMID: 34744640 PMCID: PMC8568317 DOI: 10.3389/fncir.2021.756184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/04/2021] [Indexed: 11/13/2022] Open
Abstract
AP-2 is a family of transcription factors involved in many aspects of development, cell differentiation, and regulation of cell growth and death. AP-2δ is a member of this group and specific gene expression patterns are required in the adult mouse brain for the development of parts of the inferior colliculus (IC), as well as the cortex, dorsal thalamus, and superior colliculus. The midbrain is one of the central areas in the brain where multimodal integration, i.e., integration of information from different senses, occurs. Previous data showed that AP-2δ-deficient mice are viable but due to increased apoptosis at the end of embryogenesis, lack part of the posterior midbrain. Despite the absence of the IC in AP-2δ-deficient mice, these animals retain at least some higher auditory functions. Neuronal responses to tones in the neocortex suggest an alternative auditory pathway that bypasses the IC. While sufficient data are available in mammals, little is known about AP-2δ in chickens, an avian model for the localization of sounds and the development of auditory circuits in the brain. Here, we identified and localized AP-2δ expression in the chicken midbrain during embryogenesis. Our data confirmed the presence of AP-2δ in the inferior colliculus and optic tectum (TeO), specifically in shepherd's crook neurons, which are an essential component of the midbrain isthmic network and involved in multimodal integration. AP-2δ expression in the chicken midbrain may be related to the integration of both auditory and visual afferents in these neurons. In the future, these insights may allow for a more detailed study of circuitry and computational rules of auditory and multimodal networks.
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Affiliation(s)
- Lutz Kettler
- Chair of Zoology, Technical University of Munich, Freising, Germany
| | - Hicham Sid
- Reproductive Biotechnology, Technical University of Munich, Freising, Germany
| | - Carina Schaub
- Chair of Zoology, Technical University of Munich, Freising, Germany
| | - Katharina Lischka
- Institute for Biology I, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Romina Klinger
- Reproductive Biotechnology, Technical University of Munich, Freising, Germany
| | - Markus Moser
- TranslaTUM, Technical University of Munich, Munich, Germany
| | - Benjamin Schusser
- Reproductive Biotechnology, Technical University of Munich, Freising, Germany
| | - Harald Luksch
- Chair of Zoology, Technical University of Munich, Freising, Germany
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3
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Bright AR, van Genesen S, Li Q, Grasso A, Frölich S, van der Sande M, van Heeringen SJ, Veenstra GJC. Combinatorial transcription factor activities on open chromatin induce embryonic heterogeneity in vertebrates. EMBO J 2021; 40:e104913. [PMID: 33555045 PMCID: PMC8090851 DOI: 10.15252/embj.2020104913] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 12/21/2020] [Accepted: 12/24/2020] [Indexed: 12/15/2022] Open
Abstract
During vertebrate gastrulation, mesoderm is induced in pluripotent cells, concomitant with dorsal‐ventral patterning and establishing of the dorsal axis. We applied single‐cell chromatin accessibility and transcriptome analyses to explore the emergence of cellular heterogeneity during gastrulation in Xenopus tropicalis. Transcriptionally inactive lineage‐restricted genes exhibit relatively open chromatin in animal caps, whereas chromatin accessibility in dorsal marginal zone cells more closely reflects transcriptional activity. We characterized single‐cell trajectories and identified head and trunk organizer cell clusters in early gastrulae. By integrating chromatin accessibility and transcriptome data, we inferred the activity of transcription factors in single‐cell clusters and tested the activity of organizer‐expressed transcription factors in animal caps, alone or in combination. The expression profile induced by a combination of Foxb1 and Eomes most closely resembles that observed in the head organizer. Genes induced by Eomes, Otx2, or the Irx3‐Otx2 combination are enriched for maternally regulated H3K4me3 modifications, whereas Lhx8‐induced genes are marked more frequently by zygotically controlled H3K4me3. Taken together, our results show that transcription factors cooperate in a combinatorial fashion in generally open chromatin to orchestrate zygotic gene expression.
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Affiliation(s)
- Ann Rose Bright
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Siebe van Genesen
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Qingqing Li
- Biomedical Pioneering Innovation Center, Peking University, Beijing, China
| | - Alexia Grasso
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Siebren Frölich
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Maarten van der Sande
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Simon J van Heeringen
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
| | - Gert Jan C Veenstra
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Radboud University, Nijmegen, The Netherlands
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4
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Weigele J, Bohnsack BL. Genetics Underlying the Interactions between Neural Crest Cells and Eye Development. J Dev Biol 2020; 8:jdb8040026. [PMID: 33182738 PMCID: PMC7712190 DOI: 10.3390/jdb8040026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/03/2020] [Accepted: 11/07/2020] [Indexed: 12/14/2022] Open
Abstract
The neural crest is a unique, transient stem cell population that is critical for craniofacial and ocular development. Understanding the genetics underlying the steps of neural crest development is essential for gaining insight into the pathogenesis of congenital eye diseases. The neural crest cells play an under-appreciated key role in patterning the neural epithelial-derived optic cup. These interactions between neural crest cells within the periocular mesenchyme and the optic cup, while not well-studied, are critical for optic cup morphogenesis and ocular fissure closure. As a result, microphthalmia and coloboma are common phenotypes in human disease and animal models in which neural crest cell specification and early migration are disrupted. In addition, neural crest cells directly contribute to numerous ocular structures including the cornea, iris, sclera, ciliary body, trabecular meshwork, and aqueous outflow tracts. Defects in later neural crest cell migration and differentiation cause a constellation of well-recognized ocular anterior segment anomalies such as Axenfeld–Rieger Syndrome and Peters Anomaly. This review will focus on the genetics of the neural crest cells within the context of how these complex processes specifically affect overall ocular development and can lead to congenital eye diseases.
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Affiliation(s)
- Jochen Weigele
- Division of Ophthalmology, Ann & Robert H. Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave, Chicago, IL 60611, USA;
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, 645 N. Michigan Ave, Chicago, IL 60611, USA
| | - Brenda L. Bohnsack
- Division of Ophthalmology, Ann & Robert H. Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave, Chicago, IL 60611, USA;
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, 645 N. Michigan Ave, Chicago, IL 60611, USA
- Correspondence: ; Tel.: +1-312-227-6180; Fax: +1-312-227-9411
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5
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A stemness screen reveals C3orf54/INKA1 as a promoter of human leukemia stem cell latency. Blood 2019; 133:2198-2211. [DOI: 10.1182/blood-2018-10-881441] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 02/18/2019] [Indexed: 12/17/2022] Open
Abstract
Abstract
There is a growing body of evidence that the molecular properties of leukemia stem cells (LSCs) are associated with clinical outcomes in acute myeloid leukemia (AML), and LSCs have been linked to therapy failure and relapse. Thus, a better understanding of the molecular mechanisms that contribute to the persistence and regenerative potential of LSCs is expected to result in the development of more effective therapies. We therefore interrogated functionally validated data sets of LSC-specific genes together with their known protein interactors and selected 64 candidates for a competitive in vivo gain-of-function screen to identify genes that enhanced stemness in human cord blood hematopoietic stem and progenitor cells. A consistent effect observed for the top hits was the ability to restrain early repopulation kinetics while preserving regenerative potential. Overexpression (OE) of the most promising candidate, the orphan gene C3orf54/INKA1, in a patient-derived AML model (8227) promoted the retention of LSCs in a primitive state manifested by relative expansion of CD34+ cells, accumulation of cells in G0, and reduced output of differentiated progeny. Despite delayed early repopulation, at later times, INKA1-OE resulted in the expansion of self-renewing LSCs. In contrast, INKA1 silencing in primary AML reduced regenerative potential. Mechanistically, our multidimensional confocal analysis found that INKA1 regulates G0 exit by interfering with nuclear localization of its target PAK4, with concomitant reduction of global H4K16ac levels. These data identify INKA1 as a novel regulator of LSC latency and reveal a link between the regulation of stem cell kinetics and pool size during regeneration.
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6
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Wong TCB, Rebbert M, Wang C, Chen X, Heffer A, Zarelli VE, Dawid IB, Zhao H. Genes regulated by potassium channel tetramerization domain containing 15 (Kctd15) in the developing neural crest. THE INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 2018; 60:159-66. [PMID: 27389986 DOI: 10.1387/ijdb.160058id] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Neural crest (NC) development is controlled precisely by a regulatory network with multiple signaling pathways and the involvement of many genes. The integration and coordination of these factors are still incompletely understood. Overexpression of Wnt3a and the BMP antagonist Chordin in animal cap cells from Xenopus blastulae induces a large number of NC specific genes. We previously suggested that Potassium Channel Tetramerization Domain containing 15 (Kctd15) regulates NC formation by affecting Wnt signaling and the activity of transcription factor AP-2. In order to advance understanding of the function of Kctd15 during NC development, we performed DNA microarray assays in explants injected with Wnt3a and Chordin, and identified genes that are affected by Kctd15 overexpression. Among the many genes identified, we chose Duf domain containing protein 1 (ddcp1), Platelet-Derived Growth Factor Receptor a (pdgfra), Complement factor properdin (cfp), Zinc Finger SWIM-Type Containing 5 (zswim5), and complement component 3 (C3) to examine their expression by whole mount in situ hybridization. Our work points to a possible role for Kctd15 in the regulation of NC formation and other steps in embryonic development.
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Affiliation(s)
- Thomas C B Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, P. R. China
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7
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Khedgikar V, Abbruzzese G, Mathavan K, Szydlo H, Cousin H, Alfandari D. Dual control of pcdh8l/PCNS expression and function in Xenopus laevis neural crest cells by adam13/33 via the transcription factors tfap2α and arid3a. eLife 2017; 6:26898. [PMID: 28829038 PMCID: PMC5601995 DOI: 10.7554/elife.26898] [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: 03/16/2017] [Accepted: 08/21/2017] [Indexed: 01/11/2023] Open
Abstract
Adam13/33 is a cell surface metalloprotease critical for cranial neural crest (CNC) cell migration. It can cleave multiple substrates including itself, fibronectin, ephrinB, cadherin-11, pcdh8 and pcdh8l (this work). Cleavage of cadherin-11 produces an extracellular fragment that promotes CNC migration. In addition, the adam13 cytoplasmic domain is cleaved by gamma secretase, translocates into the nucleus and regulates multiple genes. Here, we show that adam13 interacts with the arid3a/dril1/Bright transcription factor. This interaction promotes a proteolytic cleavage of arid3a and its translocation to the nucleus where it regulates another transcription factor: tfap2α. Tfap2α in turn activates multiple genes including the protocadherin pcdh8l (PCNS). The proteolytic activity of adam13 is critical for the release of arid3a from the plasma membrane while the cytoplasmic domain appears critical for the cleavage of arid3a. In addition to this transcriptional control of pcdh8l, adam13 cleaves pcdh8l generating an extracellular fragment that also regulates cell migration.
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Affiliation(s)
- Vikram Khedgikar
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, United States
| | - Genevieve Abbruzzese
- David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, United States
| | - Ketan Mathavan
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, United States.,Molecular and Cellular Biology graduate program, University of Massachusetts, Amherst, United States
| | - Hannah Szydlo
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, United States
| | - Helene Cousin
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, United States
| | - Dominique Alfandari
- Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, United States.,Molecular and Cellular Biology graduate program, University of Massachusetts, Amherst, United States
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8
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An in cellulo-derived structure of PAK4 in complex with its inhibitor Inka1. Nat Commun 2015; 6:8681. [PMID: 26607847 PMCID: PMC4674680 DOI: 10.1038/ncomms9681] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/21/2015] [Indexed: 01/09/2023] Open
Abstract
PAK4 is a metazoan-specific kinase acting downstream of Cdc42. Here we describe the structure of human PAK4 in complex with Inka1, a potent endogenous kinase inhibitor. Using single mammalian cells containing crystals 50 μm in length, we have determined the in cellulo crystal structure at 2.95 Å resolution, which reveals the details of how the PAK4 catalytic domain binds cellular ATP and the Inka1 inhibitor. The crystal lattice consists only of PAK4–PAK4 contacts, which form a hexagonal array with channels of 80 Å in diameter that run the length of the crystal. The crystal accommodates a variety of other proteins when fused to the kinase inhibitor. Inka1–GFP was used to monitor the process crystal formation in living cells. Similar derivatives of Inka1 will allow us to study the effects of PAK4 inhibition in cells and model organisms, to allow better validation of therapeutic agents targeting PAK4. PAK4 is a metazoan-specific kinase, which acts downstream of the cell polarity regulator Cdc42. Here, Baskaran et al. determine the structure of PAK4 bound to the endogenous inhibitor Inka1 from crystals that form spontaneously in mammalian cells overexpressing both proteins.
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9
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Iwasaki Y, Yumoto T, Sakakibara SI. Expression profiles of inka2 in the murine nervous system. Gene Expr Patterns 2015; 19:83-97. [PMID: 26292052 DOI: 10.1016/j.gep.2015.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 08/07/2015] [Accepted: 08/14/2015] [Indexed: 01/24/2023]
Abstract
Dynamic rearrangement of the actin cytoskeleton impacts many cellular characteristics in both the developing and adult central nervous systems (CNS), including the migration and adhesion of highly motile neural progenitor cells, axon guidance of immature neurons, and reconstruction of synaptic structures in the adult brain. Inka1, a known regulator of actin cytoskeleton reconstruction, is predominantly expressed by the neural crest cell lineage and regulates the migration and differentiation of these cells. In the present study, we identified a novel gene, designated as inka2, which is related to inka1. Inka2/fam212b is an evolutionarily conserved gene found in different vertebrate species and constitutes a novel gene family together with inka1. Northern blot analysis showed that inka2 mRNA was highly enriched in the nervous system. The spatiotemporal propagation cell profiles of those cells that expressed inka2 transcripts were compatible with those of Olig2-positive oligodendrocyte progenitor cells, which originate in the ventral ventricular zone during embryogenesis. Intense expression of inka2 was also noted in the proliferative neuronal progenitors in the developing cerebellum. On the other hand, immature newborn neurons in the embryonic brain showed no expression of inka2, except for the cells residing in the marginal zone of the embryonic telencephalon, which is known to contain transient cells including the non-subplate pioneer neurons and Cajal-Retzius cells. As brain development proceeds during the postnatal stage, inka2 expression emerged in some populations of immature neurons, including the neocortical pyramidal neurons, hippocampal pyramidal neurons, and granule cells migrating in the cerebellar cortex. In the adult brain, the expression of inka2 was interestingly confined in terminally differentiated neurons in the restricted forebrain regions. Taken together, as a novel regulator of actin cytoskeletons in the CNS, inka2 may be involved in multiple actin-driven processes, including cell migration and establishment of neuronal polarity.
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Affiliation(s)
- Yumi Iwasaki
- Laboratory for Molecular Neurobiology, Graduate School of Human Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Takahito Yumoto
- Laboratory for Molecular Neurobiology, Graduate School of Human Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan
| | - Shin-Ichi Sakakibara
- Laboratory for Molecular Neurobiology, Graduate School of Human Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan; Institute of Applied Brain Sciences, Waseda University, Tokorozawa, Saitama 359-1192, Japan.
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10
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Inhibition of neural crest formation by Kctd15 involves regulation of transcription factor AP-2. Proc Natl Acad Sci U S A 2013; 110:2870-5. [PMID: 23382213 DOI: 10.1073/pnas.1300203110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The neural crest develops in vertebrate embryos within a discrete domain at the neural plate boundary and eventually gives rise to a migrating population of cells that differentiate into a multitude of derivatives. We have shown that the broad-complex, tramtrack and bric a brac (BTB) domain-containing factor potassium channel tetramerization domain containing 15 (Kctd15) inhibits neural crest formation, and we proposed that its function is to delimit the neural crest domain. Here we report that Kctd15 is a highly effective inhibitor of transcription factor activating enhancer binding protein 2 (AP-2) in zebrafish embryos and in human cells; AP-2 is known to be critical for several steps of neural crest development. Kctd15 interacts with AP-2α but does not interfere with its nuclear localization or binding to cognate sites in the genome. Kctd15 binds specifically to the activation domain of AP-2α and efficiently inhibits transcriptional activation by a hybrid protein composed of the regulatory protein Gal4 DNA binding and AP-2α activation domains. Mutation of one proline residue in the activation domain to an alanine (P59A) yields a protein that is highly active but largely insensitive to Kctd15. These results indicate that Kctd15 acts in the embryo at least in part by specifically binding to the activation domain of AP-2α, thereby blocking the function of this critical factor in the neural crest induction hierarchy.
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11
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Reid BS, Sargent TD, Williams T. Generation and characterization of a novel neural crest marker allele, Inka1-LacZ, reveals a role for Inka1 in mouse neural tube closure. Dev Dyn 2010; 239:1188-96. [PMID: 20175189 DOI: 10.1002/dvdy.22248] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Previous studies identified Inka1 as a gene regulated by AP-2alpha in the neural crest required for craniofacial morphogenesis in fish and frog. Here, we extend the analysis of Inka1 function and regulation to the mouse by generating a LacZ knock-in allele. Inka1-LacZ allele expression occurs in the cephalic mesenchyme, heart, and paraxial mesoderm prior to E8.5. Subsequently, expression is observed in the migratory neural crest cells and their derivatives. Consistent with expression of Inka1 in tissues of the developing head during neurulation, a low percentage of Inka1(-/-) mice show exencephaly while the remainder are viable and fertile. Further studies indicate that AP-2alpha is not required for Inka1 expression in the mouse, and suggest that there is no significant genetic interaction between these two factors during embryogenesis. Together, these data demonstrate that while the expression domain of Inka1 is conserved among vertebrates, its function and regulation are not.
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Affiliation(s)
- Bethany S Reid
- Department of Craniofacial Biology and Cell and Developmental Biology, University of Colorado Denver, Aurora, Colorado 80045, USA
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12
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Hwang YS, Luo T, Xu Y, Sargent TD. Myosin-X is required for cranial neural crest cell migration in Xenopus laevis. Dev Dyn 2010; 238:2522-9. [PMID: 19718754 DOI: 10.1002/dvdy.22077] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Myosin-X (MyoX) belongs to a large family of unconventional, nonmuscle, actin-dependent motor proteins. We show that MyoX is predominantly expressed in cranial neural crest (CNC) cells in embryos of Xenopus laevis and is required for head and jaw cartilage development. Knockdown of MyoX expression using antisense morpholino oligonucleotides resulted in retarded migration of CNC cells into the pharyngeal arches, leading to subsequent hypoplasia of cartilage and inhibited outgrowth of the CNC-derived trigeminal nerve. In vitro migration assays on fibronectin using explanted CNC cells showed significant inhibition of filopodia formation, cell attachment, spreading and migration, accompanied by disruption of the actin cytoskeleton. These data support the conclusion that MyoX has an essential function in CNC migration in the vertebrate embryo.
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Affiliation(s)
- Yoo-Seok Hwang
- Laboratory of Molecular Genetics, NICHD, NIH, Bethesda, Maryland 20892, USA
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13
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Pytel P, Karrison T, Can Gong, Tonsgard JH, Krausz T, Montag AG. Neoplasms with schwannian differentiation express transcription factors known to regulate normal schwann cell development. Int J Surg Pathol 2009; 18:449-57. [PMID: 20034979 DOI: 10.1177/1066896909351698] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A number of transcription factors have been identified as important in guiding normal Schwann cell development. This study used immunohistochemistry on tissue arrays to assess the expression of some of these transcription factors (Sox5, Sox9, Sox10, AP-2α, Pax7, and FoxD3) on 76 schwannomas, 105 neurofibromas, and 34 malignant peripheral nerve sheath tumors (MPNSTs). Sox9 and Sox10 were found to be widely expressed in all tumor types. FoxD3 reactivity was stronger and more frequently found in schwannomas and MPNSTs than neurofibromas. AP-2α was positive in 31% to 49% of all tumors, but strong reactivity was limited to MPNSTs and schwannomas. Pax7 and Sox5 expression was restricted to subsets of MPNSTs. Statistical analysis showed significant differences between the 3 tumor types in the expression of these markers. No differences were found in the analyzed tumor subgroups, including schwannomas of different sites, schwannomas with or without NF2 association, neurofibromas of different types, or sporadic versus NF1-associated MPNSTs. These results suggest that the transcription factors that guide normal Schwann cell development also play a role in the biology of neoplastic cells with Schwannian differentiation. FoxD3, AP-2α, Pax7, and Sox5 are upregulated in MPNSTs compared with neurofibromas and may be markers of malignant transformation. Screening the expression of FoxD3, Sox9, and Sox10 on 23 cases of other spindle-cell proliferations that may be considered in the differential diagnosis of MPNST, including synovial sarcoma and spindle cell melanoma, suggests that these 3 are helpful markers of Schwannian differentiation in the context of diagnosing MPNSTs.
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Affiliation(s)
- Peter Pytel
- University of Chicago Medical Center, Chicago, IL, USA.
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14
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Saito Y, Gotoh M, Ujiie Y, Izutsu Y, Maéno M. Involvement of AP-2rep in morphogenesis of the axial mesoderm in Xenopus embryo. Cell Tissue Res 2008; 335:357-69. [PMID: 19048294 DOI: 10.1007/s00441-008-0712-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Accepted: 09/24/2008] [Indexed: 11/27/2022]
Abstract
We have previously isolated a cDNA clone coding for Xenopus AP-2rep (activator protein-2 repressor), a member of the Krüppel-like factor family, and reported its expression pattern in developing Xenopus embryos. In the present study, the physiological function of AP-2rep in the morphogenetic movements of the dorsal mesoderm and ectoderm was investigated. Embryos injected with either AP-2rep or VP16repC (a dominant-negative mutant) into the dorsal marginal zone at the 4-cell stage exhibited abnormal morphology in dorsal structures. Both AP-2rep and VP16repC also inhibited the elongation of animal cap explants treated with activin without affecting the expression of differentiation markers. Whole-mount in situ hybridization analysis revealed that expression of brachyury and Wnt11 was greatly suppressed by injection of VP16repC or AP-2rep morpholino, but expression was restored by the simultaneous injection of wild-type AP-2rep RNA. Furthermore, the morphogenetic abnormality induced by injection of VP16repC or AP-2rep morpholino was restored by simultaneous injection of brachyury or Wnt11 mRNA. These results show that AP-2rep is involved in the morphogenesis of the mesoderm at the gastrula stage, via the brachyury and/or Wnt pathways.
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Affiliation(s)
- Yoshinari Saito
- Graduate School of Science and Technology, Niigata University, Nishi-ku, Niigata, Japan
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Wang X, Pasolli HA, Williams T, Fuchs E. AP-2 factors act in concert with Notch to orchestrate terminal differentiation in skin epidermis. ACTA ACUST UNITED AC 2008; 183:37-48. [PMID: 18824566 PMCID: PMC2557040 DOI: 10.1083/jcb.200804030] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The mechanisms by which mammalian epidermal stem cells cease to proliferate and embark upon terminal differentiation are still poorly understood. By conditionally ablating two highly expressed transcription factors, AP-2α and AP-2γ, we unmasked functional redundancies and discovered an essential role for AP-2s in the process. In vivo and in vitro, AP-2 deficiency is accompanied by surprisingly minimal changes in basal gene expression but severely perturbed terminal differentiation and suppression of additional transcription factors and structural genes involved. In dissecting the underlying molecular pathways, we uncover parallel pathways involving AP-2 and Notch signaling, which converge to govern CCAAT/enhancer binding protein genes and orchestrate the transition from basal proliferation to suprabasal differentiation. Finally, we extend the striking similarities in compromising either Notch signaling or AP-2α/AP-2γ in developing skin to that in postnatal skin, where all hair follicles and sebaceous gland differentiation are also repressed and overt signs of premalignant conversion emerge.
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Affiliation(s)
- Xuan Wang
- The Howard Hughes Medical Institute and Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, New York, NY 10065, USA
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16
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Abstract
In a zebrafish recessive mutant young (yng), retinal cells are specified to distinct cell classes, but they fail to morphologically differentiate. A null mutation in a brahma-related gene 1 (brg1) is responsible for this phenotype. To identify retina-specific Brg1-regulated genes that control cellular differentiation, we conducted a factorial microarray analysis. Gene expression profiles were compared from wild-type and yng retinas and stage-matched whole embryos at 36 and 52 hours postfertilization (hpf). From our analysis, three categories of genes were identified: (i) Brg1-regulated retinal differentiation genes (731 probesets), (ii) retina-specific genes independent of Brg1 regulation (3,038 probesets), and (iii) Brg1-regulated genes outside the retina (107 probesets). Biological significance was confirmed by further analysis of components of the Cdk5 signaling pathway and Irx transcription factor family, representing genes identified in category 1. This study highlights the utility of factorial microarray analysis to efficiently identify relevant regulatory pathways influenced by both specific gene products and normal developmental events.
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Hoffman TL, Javier AL, Campeau SA, Knight RD, Schilling TF. Tfap2 transcription factors in zebrafish neural crest development and ectodermal evolution. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2007; 308:679-91. [PMID: 17724731 DOI: 10.1002/jez.b.21189] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Transcription factor AP2 (Tfap2) genes play essential roles in development of the epidermis and migratory cells of the neural crest (NC) in vertebrate embryos. These transcriptional activators are among the earliest genes expressed in the ectoderm and specify fates within the epidermis/crest through both direct and indirect mechanisms. The Tfap2 family arose from a single ancestral gene in a chordate ancestor that underwent gene duplication to give up to five family members in living vertebrates. This coincided with the acquisition of important roles in NC development by Tfap2 genes suggesting that this gene family was important in ectodermal evolution and possibly in the origin of NC. Here, we show that a zebrafish tfap2c is expressed in the nonneural ectoderm during early development and functions redundantly with tfap2a in NC specification. In zebrafish embryos depleted of both tfap2a and tfap2c, NC cells are virtually eliminated. Cell transplantation experiments indicate that tfap2c functions cell-autonomously in NC specification. Cells of the enveloping layer, which forms a temporary skin layer surrounding the ectoderm, also fail to differentiate or to express appropriate keratins in tfap2c deficient embryos. The role of Tfap2 genes in epidermal and NC development is considered here in the broader context of ectodermal evolution. Distinct, tissue-specific functions for Tfap2 genes in different vertebrates may reflect subfunctionalisation of an ancestral gene that consequently led to the gain of novel roles for different subfamily members in patterning the epidermis and NC.
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Affiliation(s)
- Trevor L Hoffman
- Department of Developmental and Cell Biology, University of California, Irvine, California 92697-2305, USA
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18
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Luo T, Xu Y, Hoffman TL, Zhang T, Schilling T, Sargent TD. Inca: a novel p21-activated kinase-associated protein required for cranial neural crest development. Development 2007; 134:1279-89. [PMID: 17314132 DOI: 10.1242/dev.02813] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inca (induced in neural crest by AP2) is a novel protein discovered in a microarray screen for genes that are upregulated in Xenopus embryos by the transcriptional activator protein Tfap2a. It has no significant similarity to any known protein, but is conserved among vertebrates. In Xenopus, zebrafish and mouse embryos, Inca is expressed predominantly in the premigratory and migrating neural crest (NC). Knockdown experiments in frog and fish using antisense morpholinos reveal essential functions for Inca in a subset of NC cells that form craniofacial cartilage. Cells lacking Inca migrate successfully but fail to condense into skeletal primordia. Overexpression of Inca disrupts cortical actin and prevents formation of actin "purse strings", which are required for wound healing in Xenopus embryos. We show that Inca physically interacts with p21-activated kinase 5 (PAK5), a known regulator of the actin cytoskeleton that is co-expressed with Inca in embryonic ectoderm, including in the NC. These results suggest that Inca and PAK5 cooperate in restructuring cytoskeletal organization and in the regulation of cell adhesion in the early embryo and in NC cells during craniofacial development.
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Affiliation(s)
- Ting Luo
- Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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19
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Li W, Cornell RA. Redundant activities of Tfap2a and Tfap2c are required for neural crest induction and development of other non-neural ectoderm derivatives in zebrafish embryos. Dev Biol 2006; 304:338-54. [PMID: 17258188 PMCID: PMC1904501 DOI: 10.1016/j.ydbio.2006.12.042] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 12/18/2006] [Accepted: 12/19/2006] [Indexed: 11/17/2022]
Abstract
A knockdown study suggested that transcription factor AP-2 alpha (Tfap2a) is required for neural crest induction in frog embryos. However, because Tfap2a is expressed in neural crest and in presumptive epidermis, a source of signals that induce neural crest, it was unclear whether this requirement is cell autonomous. Moreover, neural crest induction occurs normally in zebrafish tfap2a and mouse Tcfap2a mutant embryos, so it was unclear if a requirement for Tfap2a in this process has been evolutionarily conserved. Here we show that zebrafish tfap2c, encoding AP-2 gamma (Tfap2c), is expressed in non-neural ectoderm including transiently in neural crest. Inhibition of tfap2c with antisense oligonucleotides does not visibly perturb development. However, simultaneous inhibition of tfap2a and tfap2c utterly prevents neural crest induction, supporting a conserved role for Tfap2-type activity in neural crest induction. Transplant studies suggest that this role is cell-autonomous. In addition, in tfap2a/tfap2c doubly deficient embryos cranial placode derivatives are reduced, although gene expression characteristic of pre-placodal domain is normal. Unexpectedly, Rohon-Beard sensory neurons, which previous studies indicated are derived from the same precursor population as neural crest, are reduced by less than half in such embryos, implying a non-neural crest origin for a subset of them.
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Affiliation(s)
- Wei Li
- Interdisciplinary Graduate Program in Genetics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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20
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Rangarajan J, Luo T, Sargent TD. PCNS: a novel protocadherin required for cranial neural crest migration and somite morphogenesis in Xenopus. Dev Biol 2006; 295:206-18. [PMID: 16674935 DOI: 10.1016/j.ydbio.2006.03.025] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Revised: 03/16/2006] [Accepted: 03/20/2006] [Indexed: 12/26/2022]
Abstract
Protocadherins (Pcdhs), a major subfamily of cadherins, play an important role in specific intercellular interactions in development. These molecules are characterized by their unique extracellular domain (EC) with more than 5 cadherin-like repeats, a transmembrane domain (TM) and a variable cytoplasmic domain. PCNS (Protocadherin in Neural crest and Somites), a novel Pcdh in Xenopus, is initially expressed in the mesoderm during gastrulation, followed by expression in the cranial neural crest (CNC) and somites. PCNS has 65% amino acid identity to Xenopus paraxial protocadherin (PAPC) and 42-49% amino acid identity to Pcdh 8 in human, mouse, and zebrafish genomes. Overexpression of PCNS resulted in gastrulation failure but conferred little if any specific adhesion on ectodermal cells. Loss of function accomplished independently with two non-overlapping antisense morpholino oligonucleotides resulted in failure of CNC migration, leading to severe defects in the craniofacial skeleton. Somites and axial muscles also failed to undergo normal morphogenesis in these embryos. Thus, PCNS has essential functions in these two important developmental processes in Xenopus.
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Affiliation(s)
- Janaki Rangarajan
- Laboratory of Molecular Genetics, NICHD, NIH, Bethesda, MD 20892, USA
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21
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Abstract
AP-2 transcription factors are involved in cell-type-specific stimulation of proliferation and the suppression of terminal differentiation during embryonic development. Members of the family are found in mammals (with five different proteins in human and mice), frogs and fish, as well as protochordates, insects and nematodes. The AP-2 family of transcription factors consists of five different proteins in humans and mice: AP-2α, AP-2β, AP-2γ, AP-2δ and AP-2ε. Frogs and fish have known orthologs of some but not all of these proteins, and homologs of the family are also found in protochordates, insects and nematodes. The proteins have a characteristic helix-span-helix motif at the carboxyl terminus, which, together with a central basic region, mediates dimerization and DNA binding. The amino terminus contains the transactivation domain. AP-2 proteins are first expressed in primitive ectoderm of invertebrates and vertebrates; in vertebrates, they are also expressed in the emerging neural-crest cells, and AP-2α-/- animals have impairments in neural-crest-derived facial structures. AP-2β is indispensable for kidney development and AP-2γ is necessary for the formation of trophectoderm cells shortly after implantation; AP-2α and AP-2γ levels are elevated in human mammary carcinoma and seminoma. The general functions of the family appear to be the cell-type-specific stimulation of proliferation and the suppression of terminal differentiation during embryonic development.
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Affiliation(s)
- Dawid Eckert
- Department of Developmental Pathology, Institute of Pathology, Sigmund-Freud Strasse 25, 53125 Bonn, Germany
| | - Sandra Buhl
- Department of Developmental Pathology, Institute of Pathology, Sigmund-Freud Strasse 25, 53125 Bonn, Germany
| | - Susanne Weber
- Department of Developmental Pathology, Institute of Pathology, Sigmund-Freud Strasse 25, 53125 Bonn, Germany
| | - Richard Jäger
- Department of Developmental Pathology, Institute of Pathology, Sigmund-Freud Strasse 25, 53125 Bonn, Germany
| | - Hubert Schorle
- Department of Developmental Pathology, Institute of Pathology, Sigmund-Freud Strasse 25, 53125 Bonn, Germany
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