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Hu P, Wang B, Jin D, Gu Y, He H, Meng X, Zhu W, Chiang DY, Li W, MacRae CA, Zu Y. Modeling of large-scale hoxbb cluster deletions in zebrafish uncovers a role for segmentation pathways in atrioventricular boundary specification. Cell Mol Life Sci 2023; 80:317. [PMID: 37801106 PMCID: PMC11072906 DOI: 10.1007/s00018-023-04933-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 08/19/2023] [Indexed: 10/07/2023]
Abstract
Hox genes orchestrate the segmental specification of the muscular circulatory system in invertebrates but it has not proven straightforward to decipher segmental parallels in the vertebrate heart. Recently, patients with HOXB gene cluster deletion were found to exhibit abnormalities including atrioventricular canal defects. Using CRISPR, we established a mutant with the orthologous hoxbb cluster deletion in zebrafish. The mutant exhibited heart failure and atrioventricular regurgitation at 5 days. Analyzing the four genes in the hoxbb cluster, isolated deletion of hoxb1b-/- recapitulated the cardiac abnormalities, supporting hoxb1b as the causal gene. Both in situ and in vitro data indicated that hoxb1b regulates gata5 to inhibit hand2 expression and ultimately is required to pattern the vertebrate atrioventricular boundary. Together, these data reveal a role for segmental specification in vertebrate cardiac development and highlight the utility of CRISPR techniques for efficiently exploring the function of large structural genomic lesions.
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Affiliation(s)
- Peinan Hu
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Bingqi Wang
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Dongxu Jin
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Yedan Gu
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Hongyang He
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Xiangli Meng
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Wandi Zhu
- Cardiovascular Medicine Division, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - David Y Chiang
- Cardiovascular Medicine Division, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Weiming Li
- Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, 48824, USA
| | - Calum A MacRae
- Cardiovascular Medicine Division, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, 02115, USA.
| | - Yao Zu
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China.
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai, 201306, China.
- Cardiovascular Medicine Division, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, 02115, USA.
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Leino SA, Constable SCJ, Streit A, Wilkinson DG. Zbtb16 mediates a switch between Fgf signalling regimes in the developing hindbrain. Development 2023; 150:dev201319. [PMID: 37642135 PMCID: PMC10508701 DOI: 10.1242/dev.201319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 08/22/2023] [Indexed: 08/31/2023]
Abstract
Developing tissues are sequentially patterned by extracellular signals that are turned on and off at specific times. In the zebrafish hindbrain, fibroblast growth factor (Fgf) signalling has different roles at different developmental stages: in the early hindbrain, transient Fgf3 and Fgf8 signalling from rhombomere 4 is required for correct segmentation, whereas later, neuronal Fgf20 expression confines neurogenesis to specific spatial domains within each rhombomere. How the switch between these two signalling regimes is coordinated is not known. We present evidence that the Zbtb16 transcription factor is required for this transition to happen in an orderly fashion. Zbtb16 expression is high in the early anterior hindbrain, then gradually upregulated posteriorly and confined to neural progenitors. In mutants lacking functional Zbtb16, fgf3 expression fails to be downregulated and persists until a late stage, resulting in excess and more widespread Fgf signalling during neurogenesis. Accordingly, the spatial pattern of neurogenesis is disrupted in Zbtb16 mutants. Our results reveal how the distinct stage-specific roles of Fgf signalling are coordinated in the zebrafish hindbrain.
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Affiliation(s)
- Sami A. Leino
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London SE1 1UL, UK
| | - Sean C. J. Constable
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Andrea Streit
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London SE1 1UL, UK
| | - David G. Wilkinson
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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3
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Paquette E, Mumper N, Rodrigues A, Voulo M, Rich S, Roy NM. Hindbrain defects induced by Di-butyl phthalate (DBP) in developing zebrafish embryos. Neurotoxicol Teratol 2022; 92:107093. [PMID: 35477034 DOI: 10.1016/j.ntt.2022.107093] [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: 03/26/2022] [Revised: 04/17/2022] [Accepted: 04/21/2022] [Indexed: 11/28/2022]
Abstract
Di-butyl phthalate (DBP) is a globally used plasticizer found in alarmingly high concentrations in soil and water ecosystems. As phthalates are non-covalently bound to plastic polymers, phthalates easily leach into the aquatic environment. The effects of DBP on aquatic organisms is concerning, most notably, studies have focused on the endocrine-disrupting effects. However, reports on the developmental neurotoxicity of DBP are rare. Using the zebrafish vertebrate model system, we treated pre-gastrulation staged embryos with 2.5 μM DBP, a concentration environmentally noted. We find that general hindbrain structure and rhombomere patterning is disrupted at 72 h post fertilization (hpf). We investigated hindbrain specific neural patterning of cranial motor neurons and find defects in branchiomotor neuron patterning and migration. Furthermore, defects in r4 specific Mauthner neuron development were also noted. Thus, we conclude that DBP exposure during embryonic development induces defects to the hindbrain and concomitantly the neurons that are born and differentiate there.
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Affiliation(s)
- Evelyn Paquette
- Department of Biology, Sacred Heart University, Fairfield, CT, United States of America
| | - Naomi Mumper
- Department of Biology, Sacred Heart University, Fairfield, CT, United States of America
| | - Alissa Rodrigues
- Department of Biology, Sacred Heart University, Fairfield, CT, United States of America
| | - Morgan Voulo
- Department of Biology, Sacred Heart University, Fairfield, CT, United States of America
| | - Sierrah Rich
- Department of Biology, Sacred Heart University, Fairfield, CT, United States of America
| | - Nicole M Roy
- Department of Biology, Sacred Heart University, Fairfield, CT, United States of America.
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4
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Pascarelli S, Laurino P. Inter-paralog amino acid inversion events in large phylogenies of duplicated proteins. PLoS Comput Biol 2022; 18:e1010016. [PMID: 35377869 PMCID: PMC9009777 DOI: 10.1371/journal.pcbi.1010016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/14/2022] [Accepted: 03/12/2022] [Indexed: 11/25/2022] Open
Abstract
Connecting protein sequence to function is becoming increasingly relevant since high-throughput sequencing studies accumulate large amounts of genomic data. In order to go beyond the existing database annotation, it is fundamental to understand the mechanisms underlying functional inheritance and divergence. If the homology relationship between proteins is known, can we determine whether the function diverged? In this work, we analyze different possibilities of protein sequence evolution after gene duplication and identify “inter-paralog inversions”, i.e., sites where the relationship between the ancestry and the functional signal is decoupled. The amino acids in these sites are masked from being recognized by other prediction tools. Still, they play a role in functional divergence and could indicate a shift in protein function. We develop a method to specifically recognize inter-paralog amino acid inversions in a phylogeny and test it on real and simulated datasets. In a dataset built from the Epidermal Growth Factor Receptor (EGFR) sequences found in 88 fish species, we identify 19 amino acid sites that went through inversion after gene duplication, mostly located at the ligand-binding extracellular domain. Our work uncovers an outcome of protein duplications with direct implications in protein functional annotation and sequence evolution. The developed method is optimized to work with large protein datasets and can be readily included in a targeted protein analysis pipeline. Proteins are critical components of living systems because they facilitate most biological processes like protein synthesis, DNA replication, chemical catalysis, etc. Proteins are encoded in their genes. During evolution, genes accumulate mutations that get translated at the protein level. These mutations can be “neutral” if they do not affect the protein function immediately and directly; otherwise, mutations can be functional if they directly modify protein function. An event that provides an opportunity to study protein function is gene duplication namely, when two copies of a gene encoding the same protein appear. One copy of the protein often retains the same function while the other is free to diverge and specialize to a different function. This work sheds light on an alternative outcome of gene duplication that might be critical to discern between neutral and functional mutations. By looking at 88 fish genomes, we found proteins in which the evolution of their sequences does not follow the expected pattern of divergence after gene duplication. In this case, the protein sequence of a subgroup of species diverges in the copy expected to retain its function, while the sequence is retained in the expectedly divergent one. We called this event “inter-paralog amino acid inversion”. Our data shows that this “inversion” event is correlated to function, and its detection has to be considered for assigning protein functions correctly.
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Affiliation(s)
- Stefano Pascarelli
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
| | - Paola Laurino
- Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa, Japan
- * E-mail:
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Hirsch D, Kohl A, Wang Y, Sela-Donenfeld D. Axonal Projection Patterns of the Dorsal Interneuron Populations in the Embryonic Hindbrain. Front Neuroanat 2022; 15:793161. [PMID: 35002640 PMCID: PMC8738170 DOI: 10.3389/fnana.2021.793161] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Unraveling the inner workings of neural circuits entails understanding the cellular origin and axonal pathfinding of various neuronal groups during development. In the embryonic hindbrain, different subtypes of dorsal interneurons (dINs) evolve along the dorsal-ventral (DV) axis of rhombomeres and are imperative for the assembly of central brainstem circuits. dINs are divided into two classes, class A and class B, each containing four neuronal subgroups (dA1-4 and dB1-4) that are born in well-defined DV positions. While all interneurons belonging to class A express the transcription factor Olig3 and become excitatory, all class B interneurons express the transcription factor Lbx1 but are diverse in their excitatory or inhibitory fate. Moreover, within every class, each interneuron subtype displays its own specification genes and axonal projection patterns which are required to govern the stage-by-stage assembly of their connectivity toward their target sites. Remarkably, despite the similar genetic landmark of each dINs subgroup along the anterior-posterior (AP) axis of the hindbrain, genetic fate maps of some dA/dB neuronal subtypes uncovered their contribution to different nuclei centers in relation to their rhombomeric origin. Thus, DV and AP positional information has to be orchestrated in each dA/dB subpopulation to form distinct neuronal circuits in the hindbrain. Over the span of several decades, different axonal routes have been well-documented to dynamically emerge and grow throughout the hindbrain DV and AP positions. Yet, the genetic link between these distinct axonal bundles and their neuronal origin is not fully clear. In this study, we reviewed the available data regarding the association between the specification of early-born dorsal interneuron subpopulations in the hindbrain and their axonal circuitry development and fate, as well as the present existing knowledge on molecular effectors underlying the process of axonal growth.
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Affiliation(s)
- Dana Hirsch
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel.,Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Ayelet Kohl
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Yuan Wang
- Department of Biomedical Sciences, Program in Neuroscience, College of Medicine, Florida State University, Tallahassee, FL, United States
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
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Hermasch MA, Janning H, Perera RP, Schnabel V, Rostam N, Ramos-Gomes F, Muschalek W, Bennemann A, Alves F, Ralser DJ, Betz RC, Schön MP, Dosch R, Frank J. Evolutionary distinct roles of γ-secretase subunit nicastrin in zebrafish and humans. J Dermatol Sci 2022; 105:80-87. [PMID: 35016821 DOI: 10.1016/j.jdermsci.2022.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/20/2021] [Accepted: 01/03/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Mutations in the genes that encode the human γ-secretase subunits Presenilin-1, Presenilin Enhancer Protein 2, and Nicastrin (NCSTN) are associated with familial hidradenitis suppurativa (HS); and, regarding Presenilin Enhancer Protein 2, also with comorbidity for the hereditary pigmentation disorder Dowling-Degos disease. OBJECTIVE Here, the consequences of targeted inactivation of ncstn, the zebrafish homologue of human NCSTN, were studied. METHODS After morpholino (MO)-mediated ncstn-knockdown, the possibilities of phenotype rescue through co-injection of ncstn-MO with wildtype zebrafish ncstn or human NCSTN mRNA were investigated. Further, the effects of the co-injection of a human missense, nonsense, splice-site, and frameshift mutation were studied. RESULTS MO-mediated ncstn-knockdown resulted in a significant reduction in melanophore morphology, size and number; and alterations in their patterns of migration and distribution. This phenotype was rescued by co-injection of zebrafish ncstn RNA, human NCSTN RNA, or a construct encoding the human NCSTN missense mutation p.P211R. CONCLUSION Human NCSTN mutations encoding null alleles confer loss-of-function regarding pigmentation homeostasis in zebrafisch. In contrast, the human missense mutation p.P211R was less harmful, asserting sufficient residual ncstn activity to maintain pigmentation in zebrafish. Since fish lack the anatomical structures affected by HS, our data suggest that the zebrafish ncstn gene and the human NCSTN gene have probably acquired different functions during evolution. In fish, one major role of ncstn is the maintenance of pigmentation homeostasis. In contrast, one of the roles of NCSTN in humans is the prevention of inflammatory processes in the adnexal structures of the skin, as seen in familial HS.
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Affiliation(s)
- Matthias Andreas Hermasch
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | - Helena Janning
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | | | - Viktor Schnabel
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | - Nadia Rostam
- Department of Developmental Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Fernanda Ramos-Gomes
- Max Planck Institute for Experimental Medicine, Translational Molecular Imaging, Göttingen, Germany
| | - Wiebke Muschalek
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | - Anette Bennemann
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany
| | - Frauke Alves
- Max Planck Institute for Experimental Medicine, Translational Molecular Imaging, Göttingen, Germany; Clinic of Hematology and Oncology, University Medical Center Göttingen, Germany; Institute of Interventional and Diagnostic Radiology, University Medical Center Göttingen, Germany
| | | | - Regina Christine Betz
- Institute of Human Genetics, University of Bonn, Medical Faculty and University Hospital Bonn, Bonn, Germany
| | - Michael Peter Schön
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany; Lower Saxony Institute of Occupational Dermatology, University Medical Center Göttingen, Göttingen, Germany
| | - Roland Dosch
- Department of Developmental Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Jorge Frank
- Department of Dermatology, Venereology and Allergology, University Medical Center Göttingen, Göttingen, Germany.
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7
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Anderson EB, Mao Q, Ho RK. Tbx5a and Tbx5b paralogues act in combination to control separate vectors of migration in the fin field of zebrafish. Dev Biol 2022; 481:201-214. [PMID: 34756968 PMCID: PMC8665139 DOI: 10.1016/j.ydbio.2021.10.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 01/03/2023]
Abstract
The T-box containing family member, TBX5, has been shown to play important functional roles in the pectoral appendages of a variety of vertebrate species. While a single TBX5 gene exists in all tetrapods studied to date, the zebrafish genome retains two paralogues, designated as tbx5a and tbx5b, resulting from a whole genome duplication in the teleost lineage. Zebrafish deficient in tbx5a lack pectoral fin buds, whereas zebrafish deficient in tbx5b exhibit misshapen pectoral fins, showing that both paralogues function in fin development. The mesenchymal cells of the limb/fin bud are derived from the Lateral Plate Mesoderm (LPM). Previous fate mapping work in zebrafish has shown that wildtype (wt) fin field cells are initially located adjacent to somites (s)1-4. The wt fin field cells migrate in opposing diagonal directions placing the limb bud between s2-3 and lateral to the main body. To better characterize tbx5 paralogue functions in zebrafish, time-lapse analyses of the migrations of fin bud precursors under conditions of tbx5a knock-down, tbx5b knock-down and double-knock-down were performed. Our data suggest that zebrafish tbx5a and tbx5b have functionally separated migration direction vectors, that when combined recapitulate the migration of the wt fin field. We and others have shown that loss of Tbx5a function abolishes an fgf24 signaling cue resulting in fin field cells failing to converge in an Antero-Posterior (AP) direction and migrating only in a mediolateral (ML) direction. We show here that loss of Tbx5b function affects initial ML directed movements so that fin field cells fail to migrate laterally but continue to converge along the AP axis. Furthermore, fin field cells in the double Tbx5a/Tbx5b knock-down zebrafish do not engage in directed migrations along either the ML or AP axis. Therefore, these two paralogues may be acting to instruct separate vectors of fin field migration in order to direct proper fin bud formation.
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Affiliation(s)
- Erin Boyle Anderson
- Committee on Development, Regeneration and Stem Cell Biology; University of Chicago, Chicago, IL
| | - Qiyan Mao
- Committee on Development, Regeneration and Stem Cell Biology; University of Chicago, Chicago, IL,present address: Universite de Aix-Marseille; Marseille, France
| | - Robert K. Ho
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL
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Abstract
During early development, the hindbrain is sub-divided into rhombomeres that underlie the organisation of neurons and adjacent craniofacial tissues. A gene regulatory network of signals and transcription factors establish and pattern segments with a distinct anteroposterior identity. Initially, the borders of segmental gene expression are imprecise, but then become sharply defined, and specialised boundary cells form. In this Review, we summarise key aspects of the conserved regulatory cascade that underlies the formation of hindbrain segments. We describe how the pattern is sharpened and stabilised through the dynamic regulation of cell identity, acting in parallel with cell segregation. Finally, we discuss evidence that boundary cells have roles in local patterning, and act as a site of neurogenesis within the hindbrain.
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Affiliation(s)
- Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA.,Dept of Anatomy and Cell Biology, Kansas University Medical School, Kansas City, KS 66160, USA
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9
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Yamada K, Maeno A, Araki S, Kikuchi M, Suzuki M, Ishizaka M, Satoh K, Akama K, Kawabe Y, Suzuki K, Kobayashi D, Hamano N, Kawamura A. An atlas of seven zebrafish hox cluster mutants provides insights into sub/neofunctionalization of vertebrate Hox clusters. Development 2021; 148:269044. [PMID: 34096572 DOI: 10.1242/dev.198325] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 04/30/2021] [Indexed: 12/20/2022]
Abstract
Vertebrate Hox clusters are comprised of multiple Hox genes that control morphology and developmental timing along multiple body axes. Although results of genetic analyses using Hox-knockout mice have been accumulating, genetic studies in other vertebrates have not been sufficient for functional comparisons of vertebrate Hox genes. In this study, we isolated all of the seven hox cluster loss-of-function alleles in zebrafish using the CRISPR-Cas9 system. Comprehensive analysis of the embryonic phenotype and X-ray micro-computed tomography scan analysis of adult fish revealed several species-specific functional contributions of homologous Hox clusters along the appendicular axis, whereas important shared general principles were also confirmed, as exemplified by serial anterior vertebral transformations along the main body axis, observed in fish for the first time. Our results provide insights into discrete sub/neofunctionalization of vertebrate Hox clusters after quadruplication of the ancient Hox cluster. This set of seven complete hox cluster loss-of-function alleles provide a formidable resource for future developmental genetic analysis of the Hox patterning system in zebrafish.
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Affiliation(s)
- Kazuya Yamada
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Akiteru Maeno
- Plant Resource Development, Division of Genetic Resource Center, National Institute of Genetics, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - Soh Araki
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Morimichi Kikuchi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Masato Suzuki
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Mizuki Ishizaka
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Koumi Satoh
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Kagari Akama
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Yuki Kawabe
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Kenya Suzuki
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Daiki Kobayashi
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Nanami Hamano
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
| | - Akinori Kawamura
- Division of Life Science, Graduate School of Science and Engineering, Saitama University, Shimo-okubo 255, Sakura-ku, Saitama 338-8570, Japan
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10
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Beiriger A, Narayan S, Singh N, Prince V. Development and migration of the zebrafish rhombencephalic octavolateral efferent neurons. J Comp Neurol 2021; 529:1293-1307. [PMID: 32869305 PMCID: PMC8238524 DOI: 10.1002/cne.25021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/13/2020] [Accepted: 08/25/2020] [Indexed: 02/05/2023]
Abstract
In vertebrate animals, motor and sensory efferent neurons carry information from the central nervous system (CNS) to peripheral targets. These two types of efferent systems sometimes bear a close resemblance, sharing common segmental organization, axon pathways, and chemical messengers. Here, we focus on the development of the octavolateral efferent neurons (OENs) and their interactions with the closely-related facial branchiomotor neurons (FBMNs) in zebrafish. Using live-imaging approaches, we investigate the birth, migration, and projection patterns of OENs. We find that OENs are born in two distinct groups: a group of rostral efferent neurons (RENs) that arises in the fourth segment, or rhombomere (r4), of the hindbrain and a group of caudal efferent neurons (CENs) that arises in r5. Both RENs and CENs then migrate posteriorly through the hindbrain between 18 and 48 hrs postfertilization, alongside the r4-derived FBMNs. Like the FBMNs, migration of the r4-derived RENs depends on function of the segmental identity gene hoxb1a; unlike the FBMNs, however, both OEN populations move independently of prickle1b. Further, we investigate whether the previously described "pioneer" neuron that leads FBMN migration through the hindbrain is an r4-derived FBMN/REN or an r5-derived CEN. Our experiments verify that the pioneer is an r4-derived neuron and reaffirm its role in leading FBMN migration across the r4/5 border. In contrast, the r5-derived CENs migrate independently of the pioneer. Together, these results indicate that the mechanisms OENs use to navigate the hindbrain differ significantly from those employed by FBMNs.
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Affiliation(s)
- Anastasia Beiriger
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois, USA
| | - Sweta Narayan
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois, USA
| | - Noor Singh
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois, USA
| | - Victoria Prince
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois, USA
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, Illinois, USA
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11
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Singh NP, De Kumar B, Paulson A, Parrish ME, Zhang Y, Florens L, Conaway JW, Si K, Krumlauf R. A six-amino-acid motif is a major determinant in functional evolution of HOX1 proteins. Genes Dev 2020; 34:1680-1696. [PMID: 33184220 PMCID: PMC7706710 DOI: 10.1101/gad.342329.120] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/09/2020] [Indexed: 01/19/2023]
Abstract
Gene duplication and divergence is a major driver in the emergence of evolutionary novelties. How variations in amino acid sequences lead to loss of ancestral activity and functional diversification of proteins is poorly understood. We used cross-species functional analysis of Drosophila Labial and its mouse HOX1 orthologs (HOXA1, HOXB1, and HOXD1) as a paradigm to address this issue. Mouse HOX1 proteins display low (30%) sequence similarity with Drosophila Labial. However, substituting endogenous Labial with the mouse proteins revealed that HOXA1 has retained essential ancestral functions of Labial, while HOXB1 and HOXD1 have diverged. Genome-wide analysis demonstrated similar DNA-binding patterns of HOXA1 and Labial in mouse cells, while HOXB1 binds to distinct targets. Compared with HOXB1, HOXA1 shows an enrichment in co-occupancy with PBX proteins on target sites and exists in the same complex with PBX on chromatin. Functional analysis of HOXA1-HOXB1 chimeric proteins uncovered a novel six-amino-acid C-terminal motif (CTM) flanking the homeodomain that serves as a major determinant of ancestral activity. In vitro DNA-binding experiments and structural prediction show that CTM provides an important domain for interaction of HOXA1 proteins with PBX. Our findings show that small changes outside of highly conserved DNA-binding regions can lead to profound changes in protein function.
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Affiliation(s)
| | - Bony De Kumar
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Ariel Paulson
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Mark E Parrish
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Ying Zhang
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Joan W Conaway
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.,Department of Biochemistry and Molecular Biology, Kansas University Medical Center, Kansas City, Kansas 66160, USA
| | - Kausik Si
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.,Department of Molecular and Integrative Physiology, Kansas University Medical Center, Kansas City, Kansas 66160, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA.,Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, Kansas 66160, USA
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12
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Holowiecki A, Linstrum K, Ravisankar P, Chetal K, Salomonis N, Waxman JS. Pbx4 limits heart size and fosters arch artery formation by partitioning second heart field progenitors and restricting proliferation. Development 2020; 147:dev185652. [PMID: 32094112 PMCID: PMC7063670 DOI: 10.1242/dev.185652] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 02/06/2020] [Indexed: 12/11/2022]
Abstract
Vertebrate heart development requires the integration of temporally distinct differentiating progenitors. However, few signals are understood that restrict the size of the later-differentiating outflow tract (OFT). We show that improper specification and proliferation of second heart field (SHF) progenitors in zebrafish lazarus (lzr) mutants, which lack the transcription factor Pbx4, produces enlarged hearts owing to an increase in ventricular and smooth muscle cells. Specifically, Pbx4 initially promotes the partitioning of the SHF into anterior progenitors, which contribute to the OFT, and adjacent endothelial cell progenitors, which contribute to posterior pharyngeal arches. Subsequently, Pbx4 limits SHF progenitor (SHFP) proliferation. Single cell RNA sequencing of nkx2.5+ cells revealed previously unappreciated distinct differentiation states and progenitor subpopulations that normally reside within the SHF and arterial pole of the heart. Specifically, the transcriptional profiles of Pbx4-deficient nkx2.5+ SHFPs are less distinct and display characteristics of normally discrete proliferative progenitor and anterior, differentiated cardiomyocyte populations. Therefore, our data indicate that the generation of proper OFT size and arch arteries requires Pbx-dependent stratification of unique differentiation states to facilitate both homeotic-like transformations and limit progenitor production within the SHF.
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Affiliation(s)
- Andrew Holowiecki
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, USA
| | - Kelsey Linstrum
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, USA
- Molecular Genetics Graduate Program, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Padmapriyadarshini Ravisankar
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, USA
| | - Kashish Chetal
- Bioinformatics Division, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, USA
| | - Nathan Salomonis
- Bioinformatics Division, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Joshua S Waxman
- Molecular Cardiovascular Biology Division and Heart Institute, Cincinnati Children's Research Foundation, Cincinnati, OH 45229, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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13
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Parker HJ, Bronner ME, Krumlauf R. An atlas of anterior hox gene expression in the embryonic sea lamprey head: Hox-code evolution in vertebrates. Dev Biol 2019; 453:19-33. [PMID: 31071313 DOI: 10.1016/j.ydbio.2019.05.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/05/2019] [Accepted: 05/01/2019] [Indexed: 10/26/2022]
Abstract
In the hindbrain and the adjacent cranial neural crest (NC) cells of jawed vertebrates (gnathostomes), nested and segmentally-restricted domains of Hox gene expression provide a combinatorial Hox-code for specifying regional properties during head development. Extant jawless vertebrates, such as the sea lamprey (Petromyzon marinus), can provide insights into the evolution and diversification of this Hox-code in vertebrates. There is evidence for gnathostome-like spatial patterns of Hox expression in lamprey; however, the expression domains of the majority of lamprey hox genes from paralogy groups (PG) 1-4 are yet to be characterized, so it is unknown whether they are coupled to hindbrain segments (rhombomeres) and NC. In this study, we systematically describe the spatiotemporal expression of all 14 sea lamprey hox genes from PG1-PG4 in the developing hindbrain and pharynx to investigate the extent to which their expression conforms to the archetypal gnathostome hindbrain and pharyngeal hox-codes. We find many similarities in Hox expression between lamprey and gnathostome species, particularly in rhombomeric domains during hindbrain segmentation and in the cranial neural crest, enabling inference of aspects of Hox expression in the ancestral vertebrate embryonic head. These data are consistent with the idea that a Hox regulatory network underlying hindbrain segmentation is a pan vertebrate trait. We also reveal differences in hindbrain domains at later stages, as well as expression in the endostyle and in pharyngeal arch (PA) 1 mesoderm. Our analysis suggests that many Hox expression domains that are observed in extant gnathostomes were present in ancestral vertebrates but have been partitioned differently across Hox clusters in gnathostome and cyclostome lineages after duplication.
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Affiliation(s)
- Hugo J Parker
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA; Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS 66160, USA.
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14
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Frank D, Sela-Donenfeld D. Hindbrain induction and patterning during early vertebrate development. Cell Mol Life Sci 2019; 76:941-960. [PMID: 30519881 PMCID: PMC11105337 DOI: 10.1007/s00018-018-2974-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/28/2022]
Abstract
The hindbrain is a key relay hub of the central nervous system (CNS), linking the bilaterally symmetric half-sides of lower and upper CNS centers via an extensive network of neural pathways. Dedicated neural assemblies within the hindbrain control many physiological processes, including respiration, blood pressure, motor coordination and different sensations. During early development, the hindbrain forms metameric segmented units known as rhombomeres along the antero-posterior (AP) axis of the nervous system. These compartmentalized units are highly conserved during vertebrate evolution and act as the template for adult brainstem structure and function. TALE and HOX homeodomain family transcription factors play a key role in the initial induction of the hindbrain and its specification into rhombomeric cell fate identities along the AP axis. Signaling pathways, such as canonical-Wnt, FGF and retinoic acid, play multiple roles to initially induce the hindbrain and regulate Hox gene-family expression to control rhombomeric identity. Additional transcription factors including Krox20, Kreisler and others act both upstream and downstream to Hox genes, modulating their expression and protein activity. In this review, we will examine the earliest embryonic signaling pathways that induce the hindbrain and subsequent rhombomeric segmentation via Hox and other gene expression. We will examine how these signaling pathways and transcription factors interact to activate downstream targets that organize the segmented AP pattern of the embryonic vertebrate hindbrain.
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Affiliation(s)
- Dale Frank
- Department of Biochemistry, Faculty of Medicine, The Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, 31096, Haifa, Israel.
| | - Dalit Sela-Donenfeld
- Koret School of Veterinary Medicine, The Robert H Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, 76100, Rehovot, Israel.
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15
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Kavouras M, Malandrakis EE, Golomazou E, Konstantinidis I, Blom E, Palstra AP, Anastassiadis K, Panagiotaki P, Exadactylos A. Hox gene expression profiles during embryonic development of common sole. ANIM BIOL 2019. [DOI: 10.1163/15707563-17000123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Common sole (Solea solea) aquaculture production is based mostly on wild-caught breeders. Recently, the successful reproduction of first-generation fish that were reared in captivity was accomplished. A consistent good quality and quantity of produced eggs throughout the year, and of next-generation broodstock, is important for reducing the overall cost of production. Hox genes play a pivotal role in normal embryonic development and alterations of their temporal expression level may be important for egg viability. Expression profile analysis of five hox genes (hoxa1a, hoxa2a, hoxa2b, hoxb1a and hoxb1b) involved in early embryonic development and of hoxa13a, which is involved in late stages, was carried out. Results revealed a premature and/or maternal expression of hoxa13a in sole embryos, and the detection of hoxa2a and hoxa2b genes as members of paralog group 2. Principal Component Analysis of hox gene expression in 54 ± 6 hours post fertilization embryos coming from wild-caught broodstock and a first-generation one reared in the hatchery, unveiled that these broodstocks are clearly distinct. In addition, their pairwise comparison revealed significant differences in the expression levels of hoxb1a and hoxb1b genes. Hox gene regulation during embryonic development could give valuable insight into rearing sole broodstocks with different origin in concert, and also into gaining a steady mass production of eggs, either in quality or quantity, all year round.
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Affiliation(s)
- Menelaos Kavouras
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Emmanouil E. Malandrakis
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Eleni Golomazou
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Ioannis Konstantinidis
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Ewout Blom
- 2Wageningen Marine Research, Wageningen University & Research, IJmuiden, The Netherlands
| | - Arjan P. Palstra
- 3Wageningen University & Research, Animal Breeding and Genomics, Wageningen Livestock Research, Wageningen, The Netherlands
| | | | - Panagiota Panagiotaki
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
| | - Athanasios Exadactylos
- 1Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Fytokou Str., Volos, Greece
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16
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Ghosh P, Maurer JM, Sagerström CG. Analysis of novel caudal hindbrain genes reveals different regulatory logic for gene expression in rhombomere 4 versus 5/6 in embryonic zebrafish. Neural Dev 2018; 13:13. [PMID: 29945667 PMCID: PMC6020313 DOI: 10.1186/s13064-018-0112-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/19/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Previous work aimed at understanding the gene regulatory networks (GRNs) governing caudal hindbrain formation identified morphogens such as Retinoic Acid (RA) and Fibroblast growth factors (FGFs), as well as transcription factors like hoxb1b, hoxb1a, hnf1ba, and valentino as being required for rhombomere (r) r4-r6 formation in zebrafish. Considering that the caudal hindbrain is relatively complex - for instance, unique sets of neurons are formed in each rhombomere segment - it is likely that additional essential genes remain to be identified and integrated into the caudal hindbrain GRN. METHODS By taking advantage of gene expression data available in the Zebrafish Information Network (ZFIN), we identified 84 uncharacterized genes that are expressed in r4-r6. We selected a representative set of 22 genes and assayed their expression patterns in hoxb1b, hoxb1a, hnf1b, and valentino mutants with the goal of positioning them in the caudal hindbrain GRN. We also investigated the effects of RA and FGF on the expression of this gene set. To examine whether these genes are necessary for r4-r6 development, we analyzed germline mutants for six of the genes (gas6, gbx1, sall4, eglf6, celf2, and greb1l) for defects in hindbrain development. RESULTS Our results reveal that r4 gene expression is unaffected by the individual loss of hoxb1b, hoxb1a or RA, but is under the combinatorial regulation of RA together with hoxb1b. In contrast, r5/r6 gene expression is dependent on RA, FGF, hnf1ba and valentino - as individual loss of these factors abolishes r5/r6 gene expression. Our analysis of six mutant lines did not reveal rhombomere or neuronal defects, but transcriptome analysis of one line (gas6 mutant) identified expression changes for genes involved in several developmental processes - suggesting that these genes may have subtle roles in hindbrain development. CONCLUSION We conclude that r4-r6 formation is relatively robust, such that very few genes are absolutely required for this process. However, there are mechanistic differences in r4 versus r5/r6, such that no single factor is required for r4 development while several genes are individually required for r5/r6 formation.
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Affiliation(s)
- Priyanjali Ghosh
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St/LRB815, Worcester, MA, USA
| | - Jennifer M Maurer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St/LRB815, Worcester, MA, USA
| | - Charles G Sagerström
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St/LRB815, Worcester, MA, USA.
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17
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Addison M, Xu Q, Cayuso J, Wilkinson DG. Cell Identity Switching Regulated by Retinoic Acid Signaling Maintains Homogeneous Segments in the Hindbrain. Dev Cell 2018; 45:606-620.e3. [PMID: 29731343 PMCID: PMC5988564 DOI: 10.1016/j.devcel.2018.04.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/16/2018] [Accepted: 04/04/2018] [Indexed: 10/25/2022]
Abstract
The patterning of tissues to form subdivisions with distinct and homogeneous regional identity is potentially disrupted by cell intermingling. Transplantation studies suggest that homogeneous segmental identity in the hindbrain is maintained by identity switching of cells that intermingle into another segment. We show that switching occurs during normal development and is mediated by feedback between segment identity and the retinoic acid degrading enzymes, cyp26b1 and cyp26c1. egr2, which specifies the segmental identity of rhombomeres r3 and r5, underlies the lower expression level of cyp26b1 and cyp26c1 in r3 and r5 compared with r2, r4, and r6. Consequently, r3 or r5 cells that intermingle into adjacent segments encounter cells with higher cyp26b1/c1 expression, which we find is required for downregulation of egr2b expression. Furthermore, egr2b expression is regulated in r2, r4, and r6 by non-autonomous mechanisms that depend upon the number of neighbors that express egr2b. These findings reveal that a community regulation of retinoid signaling maintains homogeneous segmental identity.
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Affiliation(s)
- Megan Addison
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Qiling Xu
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jordi Cayuso
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David G Wilkinson
- Neural Development Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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18
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Selland LG, Koch S, Laraque M, Waskiewicz AJ. Coordinate regulation of retinoic acid synthesis by pbx genes and fibroblast growth factor signaling by hoxb1b is required for hindbrain patterning and development. Mech Dev 2018; 150:28-41. [PMID: 29496480 DOI: 10.1016/j.mod.2018.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 10/17/2022]
Abstract
The vertebrate hindbrain is composed of a series of lineage-restricted segments termed rhombomeres. Segment-specific gene expression drives unique programs of neuronal differentiation. Two critical embryonic signaling pathways, Fibroblast Growth Factor (FGF) and Retinoic Acid (RA), regulate early embryonic rhombomere patterning. The earliest expressed hox genes, hoxb1b and hoxb1a in zebrafish, are logical candidates for establishing signaling networks that specify segmental identity. We sought to determine the mechanism by which hox genes regulate hindbrain patterning in zebrafish. We demonstrate that hoxb1a regulates r4-specific patterning, while hoxb1b regulates rhombomere segmentation and size. Hoxb1a and hoxb1b redundantly regulate vhnf1 expression. Loss of hoxb1b together with pbx4 reverts the hindbrain to a groundstate identity, demonstrating the importance of hox genes in patterning nearly the entire hindbrain, and a key requirement for Pbx in this process. Additionally, we provide evidence that while pbx genes regulate RA signaling, hoxb1b regulates hindbrain identity through complex regulation of FGF signaling.
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Affiliation(s)
- Lyndsay G Selland
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Sophie Koch
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Malcolm Laraque
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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19
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Parker HJ, Krumlauf R. Segmental arithmetic: summing up the Hox gene regulatory network for hindbrain development in chordates. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [PMID: 28771970 DOI: 10.1002/wdev.286] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 06/13/2017] [Accepted: 06/15/2017] [Indexed: 11/10/2022]
Abstract
Organization and development of the early vertebrate hindbrain are controlled by a cascade of regulatory interactions that govern the process of segmentation and patterning along the anterior-posterior axis via Hox genes. These interactions can be assembled into a gene regulatory network that provides a framework to interpret experimental data, generate hypotheses, and identify gaps in our understanding of the progressive process of hindbrain segmentation. The network can be broadly separated into a series of interconnected programs that govern early signaling, segmental subdivision, secondary signaling, segmentation, and ultimately specification of segmental identity. Hox genes play crucial roles in multiple programs within this network. Furthermore, the network reveals properties and principles that are likely to be general to other complex developmental systems. Data from vertebrate and invertebrate chordate models are shedding light on the origin and diversification of the network. Comprehensive cis-regulatory analyses of vertebrate Hox gene regulation have enabled powerful cross-species gene regulatory comparisons. Such an approach in the sea lamprey has revealed that the network mediating segmental Hox expression was present in ancestral vertebrates and has been maintained across diverse vertebrate lineages. Invertebrate chordates lack hindbrain segmentation but exhibit conservation of some aspects of the network, such as a role for retinoic acid in establishing nested Hox expression domains. These comparisons lead to a model in which early vertebrates underwent an elaboration of the network between anterior-posterior patterning and Hox gene expression, leading to the gene-regulatory programs for segmental subdivision and rhombomeric segmentation. WIREs Dev Biol 2017, 6:e286. doi: 10.1002/wdev.286 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Hugo J Parker
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, USA.,Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, Kansas 66160, USA
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20
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Dong X, Li J, He L, Gu C, Jia W, Yue Y, Li J, Zhang Q, Chu L, Zhao Q. Zebrafish Znfl1 proteins control the expression of hoxb1b gene in the posterior neuroectoderm by acting upstream of pou5f3 and sall4 genes. J Biol Chem 2017. [PMID: 28623229 DOI: 10.1074/jbc.m117.777094] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Transcription factors play crucial roles in patterning posterior neuroectoderm. Previously, zinc finger transcription factor znfl1 was reported to be expressed in the posterior neuroectoderm of zebrafish embryos. However, its roles remain unknown. Here, we report that there are 13 copies of znfl1 in the zebrafish genome, and all the paralogues share highly identical protein sequences and cDNA sequences. When znfl1s are knocked down using a morpholino to inhibit their translation or dCas9-Eve to inhibit their transcription, the zebrafish gastrula displays reduced expression of hoxb1b, the marker gene for the posterior neuroectoderm. Further analyses reveal that diminishing znfl1s produces the decreased expressions of pou5f3, whereas overexpression of pou5f3 effectively rescues the reduced expression of hoxb1b in the posterior neuroectoderm. Additionally, knocking down znfl1s causes the reduced expression of sall4, a direct regulator of pou5f3, in the posterior neuroectoderm, and overexpression of sall4 rescues the expression of pou5f3 in the knockdown embryos. In contrast, knocking down either pou5f3 or sall4 does not affect the expressions of znfl1s Taken together, our results demonstrate that zebrafish znfl1s control the expression of hoxb1b in the posterior neuroectoderm by acting upstream of pou5f3 and sall4.
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Affiliation(s)
- Xiaohua Dong
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China; Institute of Genome Editing, Nanjing YSY Biotech Company, Limited, Nanjing 211812, China
| | - Jingyun Li
- Maternal and Child Health Medical Institute, Department of Plastic and Cosmetic Surgery, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University, Nanjing 210004, China
| | - Luqingqing He
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China
| | - Chun Gu
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China
| | - Wenshuang Jia
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China
| | - Yunyun Yue
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China
| | - Jun Li
- Maternal and Child Health Medical Institute, Department of Plastic and Cosmetic Surgery, Obstetrics and Gynecology Hospital Affiliated to Nanjing Medical University, Nanjing 210004, China
| | - Qinxin Zhang
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China
| | - Lele Chu
- Institute of Genome Editing, Nanjing YSY Biotech Company, Limited, Nanjing 211812, China
| | - Qingshun Zhao
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, China.
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21
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Hall TE, Martel N, Lo HP, Xiong Z, Parton RG. A plasmid library of full-length zebrafish rab proteins for in vivo cell biology. CELLULAR LOGISTICS 2017; 7:e1301151. [PMID: 28396820 DOI: 10.1080/21592799.2017.1301151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/18/2017] [Indexed: 02/03/2023]
Abstract
The zebrafish is an emerging model for highly sophisticated medium-throughput experiments such as genetic and chemical screens. However, studies of entire protein families within this context are often hampered by poor genetic resources such as clone libraries. Here we describe a complete collection of 76 full-length open reading frame clones for the zebrafish rab protein family. While the mouse genome contains 60 rab genes and the human genome 63, we find that 18 zebrafish rab genes have 2, and in the case of rab38, 3 paralogues. In contrast, we were unable to identify zebrafish orthologues of the mammalian Rab2b, Rab17 or Rab29. We make this resource available through the Addgene repository to facilitate cell biologic approaches using this model.
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Affiliation(s)
- Thomas E Hall
- Institute for Molecular Bioscience, University of Queensland , Brisbane, Queensland, Australia
| | - Nick Martel
- Institute for Molecular Bioscience, University of Queensland , Brisbane, Queensland, Australia
| | - Harriet P Lo
- Institute for Molecular Bioscience, University of Queensland , Brisbane, Queensland, Australia
| | - Zherui Xiong
- Institute for Molecular Bioscience, University of Queensland , Brisbane, Queensland, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, Australia; Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, Queensland, Australia
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22
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Hale ME, Katz HR, Peek MY, Fremont RT. Neural circuits that drive startle behavior, with a focus on the Mauthner cells and spiral fiber neurons of fishes. J Neurogenet 2016; 30:89-100. [DOI: 10.1080/01677063.2016.1182526] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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23
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Parker HJ, Bronner ME, Krumlauf R. The vertebrate Hox gene regulatory network for hindbrain segmentation: Evolution and diversification: Coupling of a Hox gene regulatory network to hindbrain segmentation is an ancient trait originating at the base of vertebrates. Bioessays 2016; 38:526-38. [PMID: 27027928 DOI: 10.1002/bies.201600010] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hindbrain development is orchestrated by a vertebrate gene regulatory network that generates segmental patterning along the anterior-posterior axis via Hox genes. Here, we review analyses of vertebrate and invertebrate chordate models that inform upon the evolutionary origin and diversification of this network. Evidence from the sea lamprey reveals that the hindbrain regulatory network generates rhombomeric compartments with segmental Hox expression and an underlying Hox code. We infer that this basal feature was present in ancestral vertebrates and, as an evolutionarily constrained developmental state, is fundamentally important for patterning of the vertebrate hindbrain across diverse lineages. Despite the common ground plan, vertebrates exhibit neuroanatomical diversity in lineage-specific patterns, with different vertebrates revealing variations of Hox expression in the hindbrain that could underlie this diversification. Invertebrate chordates lack hindbrain segmentation but exhibit some conserved aspects of this network, with retinoic acid signaling playing a role in establishing nested domains of Hox expression.
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Affiliation(s)
- Hugo J Parker
- Stowers Institute for Medical Research, Kansas City, MO, USA
| | - Marianne E Bronner
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Robb Krumlauf
- Stowers Institute for Medical Research, Kansas City, MO, USA.,Department of Anatomy and Cell Biology, Kansas University Medical Center, Kansas City, KS, USA
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24
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Abstract
The subdivision of tissues into sharply demarcated regions with distinct and homogenous identity is an essential aspect of embryonic development. Along the anteroposterior axis of the vertebrate nervous system, this involves signaling which induces spatially restricted expression of transcription factors that specify regional identity. The spatial expression of such transcription factors is initially imprecise, with overlapping expression of genes that specify distinct identities, and a ragged border at the interface of adjacent regions. This pattern becomes sharpened by establishment of mutually exclusive expression of transcription factors, and by cell segregation that underlies formation of a straight border. In this review, we discuss studies of the vertebrate hindbrain which have revealed how discrete regional identity is established, the roles of Eph-ephrin signaling in cell segregation and border sharpening, and how cell identity and cell segregation are coupled.
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25
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McEllin JA, Alexander TB, Tümpel S, Wiedemann LM, Krumlauf R. Analyses of fugu hoxa2 genes provide evidence for subfunctionalization of neural crest cell and rhombomere cis-regulatory modules during vertebrate evolution. Dev Biol 2016; 409:530-42. [DOI: 10.1016/j.ydbio.2015.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/08/2015] [Accepted: 11/08/2015] [Indexed: 12/22/2022]
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26
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Vega‐López GA, Bonano M, Tríbulo C, Fernández JP, Agüero TH, Aybar MJ. Functional analysis of
Hairy
genes in
Xenopus
neural crest initial specification and cell migration. Dev Dyn 2015; 244:988-1013. [DOI: 10.1002/dvdy.24295] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 04/25/2015] [Accepted: 05/14/2015] [Indexed: 01/28/2023] Open
Affiliation(s)
| | - Marcela Bonano
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET‐UNT
| | - Celeste Tríbulo
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET‐UNT
- Instituto de Biología “Dr. Francisco D. Barbieri”, Facultad de Bioquímica, Química y FarmaciaUniversidad Nacional de TucumánChacabuco San Miguel de Tucumán Argentina
| | - Juan P. Fernández
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET‐UNT
| | - Tristán H. Agüero
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET‐UNT
| | - Manuel J. Aybar
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET‐UNT
- Instituto de Biología “Dr. Francisco D. Barbieri”, Facultad de Bioquímica, Química y FarmaciaUniversidad Nacional de TucumánChacabuco San Miguel de Tucumán Argentina
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27
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Labalette C, Wassef MA, Desmarquet-Trin Dinh C, Bouchoucha YX, Le Men J, Charnay P, Gilardi-Hebenstreit P. Molecular dissection of segment formation in the developing hindbrain. Development 2015; 142:185-95. [PMID: 25516974 DOI: 10.1242/dev.109652] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Although many components of the genetic pathways that provide positional information during embryogenesis have been identified, it remains unclear how these signals are integrated to specify discrete tissue territories. Here, we investigate the molecular mechanisms underlying the formation of one of the hindbrain segments, rhombomere (r) 3, specified by the expression of the gene krox20. Dissecting krox20 transcriptional regulation has identified several input pathways: Hox paralogous 1 (PG1) factors, which both directly activate krox20 and indirectly repress it via Nlz factors, and the molecular components of an Fgf-dependent effector pathway. These different inputs are channelled through a single initiator enhancer element to shape krox20 initial transcriptional response: Hox PG1 and Nlz factors define the anterior-posterior extent of the enhancer's domain of activity, whereas Fgf signalling modulates the magnitude of activity in a spatially uniform manner. Final positioning of r3 boundaries requires interpretation of this initial pattern by a krox20 positive-feedback loop, orchestrated by another enhancer. Overall, this study shows how positional information provided by different patterning mechanisms is integrated through a gene regulatory network involving two cis-acting elements operating on the same gene, thus offering a comprehensive view of the delimitation of a territory.
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Affiliation(s)
- Charlotte Labalette
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France
| | - Michel Adam Wassef
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France Sorbonne Universités, UPMC Univ Paris 06, IFD, 4 Place Jussieu, Paris 75252, Cedex 05, France
| | - Carole Desmarquet-Trin Dinh
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France
| | - Yassine Xavier Bouchoucha
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France Sorbonne Universités, UPMC Univ Paris 06, IFD, 4 Place Jussieu, Paris 75252, Cedex 05, France
| | - Johan Le Men
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France Sorbonne Universités, UPMC Univ Paris 06, IFD, 4 Place Jussieu, Paris 75252, Cedex 05, France
| | - Patrick Charnay
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France
| | - Pascale Gilardi-Hebenstreit
- Ecole Normale Supérieure, Institut de Biologie de l'ENS (IBENS), Inserm U1024, CNRS UMR 8197, Paris F-75005, France
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Weicksel SE, Gupta A, Zannino DA, Wolfe SA, Sagerström CG. Targeted germ line disruptions reveal general and species-specific roles for paralog group 1 hox genes in zebrafish. BMC DEVELOPMENTAL BIOLOGY 2014; 14:25. [PMID: 24902847 PMCID: PMC4061917 DOI: 10.1186/1471-213x-14-25] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 05/27/2014] [Indexed: 01/04/2023]
Abstract
Background The developing vertebrate hindbrain is transiently segmented into rhombomeres by a process requiring Hox activity. Hox genes control specification of rhombomere fates, as well as the stereotypic differentiation of rhombomere-specific neuronal populations. Accordingly, germ line disruption of the paralog group 1 (PG1) Hox genes Hoxa1 and Hoxb1 causes defects in hindbrain segmentation and neuron formation in mice. However, antisense-mediated interference with zebrafish hoxb1a and hoxb1b (analogous to murine Hoxb1 and Hoxa1, respectively) produces phenotypes that are qualitatively and quantitatively distinct from those observed in the mouse. This suggests that PG1 Hox genes may have species-specific functions, or that anti-sense mediated interference may not completely inactivate Hox function in zebrafish. Results Using zinc finger and TALEN technologies, we disrupted hoxb1a and hoxb1b in the zebrafish germ line to establish mutant lines for each gene. We find that zebrafish hoxb1a germ line mutants have a more severe phenotype than reported for Hoxb1a antisense treatment. This phenotype is similar to that observed in Hoxb1 knock out mice, suggesting that Hoxb1/hoxb1a have the same function in both species. Zebrafish hoxb1b germ line mutants also have a more severe phenotype than reported for hoxb1b antisense treatment (e.g. in the effect on Mauthner neuron differentiation), but this phenotype differs from that observed in Hoxa1 knock out mice (e.g. in the specification of rhombomere 5 (r5) and r6), suggesting that Hoxa1/hoxb1b have species-specific activities. We also demonstrate that Hoxb1b regulates nucleosome organization at the hoxb1a promoter and that retinoic acid acts independently of hoxb1b to activate hoxb1a expression. Conclusions We generated several novel germ line mutants for zebrafish hoxb1a and hoxb1b. Our analyses indicate that Hoxb1 and hoxb1a have comparable functions in zebrafish and mouse, suggesting a conserved function for these genes. In contrast, while Hoxa1 and hoxb1b share functions in the formation of r3 and r4, they differ with regards to r5 and r6, where Hoxa1 appears to control formation of r5, but not r6, in the mouse, whereas hoxb1b regulates formation of r6, but not r5, in zebrafish. Lastly, our data reveal independent regulation of hoxb1a expression by retinoic acid and Hoxb1b in zebrafish.
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Affiliation(s)
| | | | | | | | - Charles G Sagerström
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation St,/LRB815, Worcester, MA 01605-2324, USA.
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29
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Choe SK, Ladam F, Sagerström CG. TALE factors poise promoters for activation by Hox proteins. Dev Cell 2014; 28:203-11. [PMID: 24480644 DOI: 10.1016/j.devcel.2013.12.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 11/08/2013] [Accepted: 12/19/2013] [Indexed: 01/09/2023]
Abstract
Hox proteins form complexes with TALE cofactors from the Pbx and Prep/Meis families to control transcription, but it remains unclear how Hox:TALE complexes function. Examining a Hoxb1b:TALE complex that regulates zebrafish hoxb1a transcription, we find maternally deposited TALE proteins at the hoxb1a promoter already during blastula stages. These TALE factors recruit histone-modifying enzymes to promote an active chromatin profile at the hoxb1a promoter and also recruit RNA polymerase II (RNAPII) and P-TEFb. However, in the presence of TALE factors, RNAPII remains phosphorylated on serine 5 and hoxb1a transcription is inefficient. By gastrula stages, Hoxb1b binds together with TALE factors to the hoxb1a promoter. This triggers P-TEFb-mediated transitioning of RNAPII to the serine 2-phosphorylated form and efficient hoxb1a transcription. We conclude that TALE factors access promoters during early embryogenesis to poise them for activation but that Hox proteins are required to trigger efficient transcription.
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Affiliation(s)
- Seong-Kyu Choe
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Franck Ladam
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Charles G Sagerström
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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30
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Zigman M, Laumann-Lipp N, Titus T, Postlethwait J, Moens CB. Hoxb1b controls oriented cell division, cell shape and microtubule dynamics in neural tube morphogenesis. Development 2014; 141:639-49. [PMID: 24449840 PMCID: PMC3899817 DOI: 10.1242/dev.098731] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hox genes are classically ascribed to function in patterning the anterior-posterior axis of bilaterian animals; however, their role in directing molecular mechanisms underlying morphogenesis at the cellular level remains largely unstudied. We unveil a non-classical role for the zebrafish hoxb1b gene, which shares ancestral functions with mammalian Hoxa1, in controlling progenitor cell shape and oriented cell division during zebrafish anterior hindbrain neural tube morphogenesis. This is likely distinct from its role in cell fate acquisition and segment boundary formation. We show that, without affecting major components of apico-basal or planar cell polarity, Hoxb1b regulates mitotic spindle rotation during the oriented neural keel symmetric mitoses that are required for normal neural tube lumen formation in the zebrafish. This function correlates with a non-cell-autonomous requirement for Hoxb1b in regulating microtubule plus-end dynamics in progenitor cells in interphase. We propose that Hox genes can influence global tissue morphogenesis by control of microtubule dynamics in individual cells in vivo.
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Affiliation(s)
- Mihaela Zigman
- Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 329, 69120 Heidelberg, Germany
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31
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Structural and temporal requirements of Wnt/PCP protein Vangl2 function for convergence and extension movements and facial branchiomotor neuron migration in zebrafish. Mech Dev 2013; 131:1-14. [PMID: 24333599 DOI: 10.1016/j.mod.2013.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 11/28/2013] [Accepted: 12/01/2013] [Indexed: 01/07/2023]
Abstract
Van gogh-like 2 (Vangl2), a core component of the Wnt/planar cell polarity (PCP) signaling pathway, is a four-pass transmembrane protein with N-terminal and C-terminal domains located in the cytosol, and is structurally conserved from flies to mammals. In vertebrates, Vangl2 plays an essential role in convergence and extension (CE) movements during gastrulation and in facial branchiomotor (FBM) neuron migration in the hindbrain. However, the roles of specific Vangl2 domains, of membrane association, and of specific extracellular and intracellular motifs have not been examined, especially in the context of FBM neuron migration. Through heat shock-inducible expression of various Vangl2 transgenes, we found that membrane associated functions of the N-terminal and C-terminal domains of Vangl2 are involved in regulating FBM neuron migration. Importantly, through temperature shift experiments, we found that the critical period for Vangl2 function coincides with the initial stages of FBM neuron migration out of rhombomere 4. Intriguingly, we have also uncovered a putative nuclear localization motif in the C-terminal domain that may play a role in regulating CE movements.
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32
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Wanner SJ, Saeger I, Guthrie S, Prince VE. Facial motor neuron migration advances. Curr Opin Neurobiol 2013; 23:943-50. [PMID: 24090878 DOI: 10.1016/j.conb.2013.09.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 09/03/2013] [Indexed: 11/19/2022]
Abstract
During development, the migration of specific neuronal subtypes is required for the correct establishment of neural circuits. In mice and zebrafish, facial branchiomotor (FBM) neurons undergo a tangential migration from rhombomere 4 caudally through the hindbrain. Recent advances in the field have capitalized on genetic studies in zebrafish and mouse, and high-resolution time-lapse imaging in zebrafish. Planar cell polarity signaling has emerged as a critical conserved factor in FBM neuron migration, functioning both within the neurons and their environment. In zebrafish, migration depends on specialized 'pioneer' neurons to lead follower FBM neurons through the hindbrain, and on interactions with structural components including pre-laid axon tracts and the basement membrane. Despite fundamental conservation, species-specific differences in migration mechanisms are being uncovered.
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Affiliation(s)
- Sarah J Wanner
- Department of Organismal Biology and Anatomy, The University of Chicago, 1027 E 57th Street, Chicago, IL 60637, United States
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33
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Schulte D, Frank D. TALE transcription factors during early development of the vertebrate brain and eye. Dev Dyn 2013; 243:99-116. [DOI: 10.1002/dvdy.24030] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 07/11/2013] [Accepted: 07/13/2013] [Indexed: 12/25/2022] Open
Affiliation(s)
- Dorothea Schulte
- Institute of Neurology (Edinger Institute); University Hospital Frankfurt, J.W. Goethe University; Frankfurt Germany
| | - Dale Frank
- Department of Biochemistry; The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology; Haifa Israel
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Drummond DL, Cheng CS, Selland LG, Hocking JC, Prichard LB, Waskiewicz AJ. The role of Zic transcription factors in regulating hindbrain retinoic acid signaling. BMC DEVELOPMENTAL BIOLOGY 2013; 13:31. [PMID: 23937294 PMCID: PMC3751700 DOI: 10.1186/1471-213x-13-31] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 08/05/2013] [Indexed: 01/05/2023]
Abstract
Background The reiterated architecture of cranial motor neurons aligns with the segmented structure of the embryonic vertebrate hindbrain. Anterior-posterior identity of cranial motor neurons depends, in part, on retinoic acid signaling levels. The early vertebrate embryo maintains a balance between retinoic acid synthetic and degradative zones on the basis of reciprocal expression domains of the retinoic acid synthesis gene aldhehyde dehydrogenase 1a2 (aldh1a2) posteriorly and the oxidative gene cytochrome p450 type 26a1 (cyp26a1) in the forebrain, midbrain, and anterior hindbrain. Results This manuscript investigates the role of zinc finger of the cerebellum (zic) transcription factors in regulating levels of retinoic acid and differentiation of cranial motor neurons. Depletion of zebrafish Zic2a and Zic2b results in a strong downregulation of aldh1a2 expression and a concomitant reduction in activity of a retinoid-dependent transgene. The vagal motor neuron phenotype caused by loss of Zic2a/2b mimics a depletion of Aldh1a2 and is rescued by exogenously supplied retinoic acid. Conclusion Zic transcription factors function in patterning hindbrain motor neurons through their regulation of embryonic retinoic acid signaling.
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Affiliation(s)
- Danna L Drummond
- Department of Biological Sciences, University of Alberta, CW405, Edmonton, AB T6G 2E9, Canada
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35
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Pérez-Fernández J, Megías M, Pombal MA. Distribution of a Y1 receptor mRNA in the brain of two Lamprey species, the sea lamprey (Petromyzon marinus) and the river Lamprey (Lampetra fluviatilis). J Comp Neurol 2013; 521:426-47. [PMID: 22740099 DOI: 10.1002/cne.23180] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 05/23/2012] [Accepted: 06/22/2012] [Indexed: 11/09/2022]
Abstract
The neuropeptide Y system consists of several neuropeptides acting through a broad number of receptor subtypes, the NPY family of receptors. NPY receptors are divided into three subfamilies (Y1, Y2, and Y5) that display a complex evolutionary history due to local and large-scale gene duplication events and gene losses. Lampreys emerged from a basal branch of the tree of vertebrates and they are in a key position to shed light on the evolutionary history of the NPY system. One member of the Y1 subfamily has been reported in agnathans, but the phylogenetic tree of the Y1 subfamily is not yet clear. We cloned the sequences of the Y1-subtype receptor of Petromyzon marinus and Lampetra fluviatilis to study the expression pattern of this receptor in lampreys by in situ hybridization and to analyze the phylogeny of the Y1-subfamily receptors in vertebrates. The phylogenetic study showed that the Y1 receptor of lampreys is basal to the Y1/6 branch of the Y1-subfamily receptors. In situ hybridization showed that the Y1 receptor is widely expressed throughout the brain of lampreys, with some regions showing numerous positive neurons, as well as the presence of numerous cerebrospinal fluid-contacting cells in the spinal cord. This broad distribution of the lamprey Y1 receptor is more similar to that found in other vertebrates for the Y1 receptor than that of the other members of the Y1 subfamily: Y4, Y8, and Y6 receptors. Both phylogenetic relationship and expression pattern suggest that this receptor is a Y1 receptor.
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Affiliation(s)
- Juan Pérez-Fernández
- Neurolam Group, Department of Functional Biology and Health Sciences, University of Vigo, Vigo, Spain
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36
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Kanda M, Ikeda T, Fujiwara S. Identification of a retinoic acid-responsive neural enhancer in the Ciona intestinalis Hox1 gene. Dev Growth Differ 2013; 55:260-9. [PMID: 23302037 DOI: 10.1111/dgd.12033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/06/2012] [Accepted: 12/06/2012] [Indexed: 12/16/2022]
Abstract
The Hox1 gene in the urochordate ascidian Ciona intestinalis (Ci-Hox1) is expressed in the nerve cord and epidermis. We identified a nerve cord enhancer in the second intron of Ci-Hox1, and demonstrated that retinoic acid (RA) plays a major role in activating this enhancer. The enhancer contained a putative retinoic acid-response element (RARE). Mutation of the RARE in the Ci-Hox1 nerve cord enhancer only partially abolished the enhancer activity. Genes encoding RA synthase and the RA receptor were knocked down using specific antisense morpholino oligos (MOs), and injection of embryos with these MOs resulted in the complete disappearance of epidermal expression of Ci-Hox1 and reduction of neural expression. However, nerve cord expression was not completely repressed. These results suggest that the nerve cord enhancer is activated by two partially redundant pathways; one RA-dependent and one RA-independent.
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Affiliation(s)
- Miyuki Kanda
- Department of Applied Science, Kochi University, 2-5-1 Akebono-cho, Kochi, 780-8520, Japan.
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37
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Gaunt SJ, Paul YL. Changes in Cis-regulatory Elements during Morphological Evolution. BIOLOGY 2012; 1:557-74. [PMID: 24832508 PMCID: PMC4009813 DOI: 10.3390/biology1030557] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/30/2012] [Accepted: 10/09/2012] [Indexed: 11/23/2022]
Abstract
How have animals evolved new body designs (morphological evolution)? This requires explanations both for simple morphological changes, such as differences in pigmentation and hair patterns between different Drosophila populations and species, and also for more complex changes, such as differences in the forelimbs of mice and bats, and the necks of amphibians and reptiles. The genetic changes and pathways involved in these evolutionary steps require identification. Many, though not all, of these events occur by changes in cis-regulatory (enhancer) elements within developmental genes. Enhancers are modular, each affecting expression in only one or a few tissues. Therefore it is possible to add, remove or alter an enhancer without producing changes in multiple tissues, and thereby avoid widespread (pleiotropic) deleterious effects. Ideally, for a given step in morphological evolution it is necessary to identify (i) the change in phenotype, (ii) the changes in gene expression, (iii) the DNA region, enhancer or otherwise, affected, (iv) the mutation involved, (v) the nature of the transcription or other factors that bind to this site. In practice these data are incomplete for most of the published studies upon morphological evolution. Here, the investigations are categorized according to how far these analyses have proceeded.
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Affiliation(s)
| | - Yu-Lee Paul
- The Babraham Institute, Babraham, Cambridge, CB22 3AT, UK.
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38
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Zannino DA, Sagerström CG, Appel B. olig2-Expressing hindbrain cells are required for migrating facial motor neurons. Dev Dyn 2012; 241:315-26. [PMID: 22275004 DOI: 10.1002/dvdy.23718] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The complicated trajectory of facial motor neuron migration requires coordination of intrinsic signals and cues from the surrounding environment. Migration begins in rhombomere (r) 4 where facial motor neurons are born and proceeds in a caudal direction. Once facial motor neurons reach their target rhombomeres, they migrate laterally and radially from the ventral neural tube. In zebrafish, as facial motor neurons migrate through r5/r6, they pass near cells that express olig2, which encodes a bHLH transcription factor. In this study, we found that olig2 function is required for facial motor neurons to complete their caudal migration into r6 and r7 and form stereotypical clusters. Additionally, embryos that lack mafba function, in which facial motor neurons also fail to complete caudal migration, lack olig2 expression in r5 and r6. Our data raise the possibility that cells expressing olig2 are intermediate targets that help guide facial motor neuron migration.
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Affiliation(s)
- Denise A Zannino
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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39
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Marotta M, Piontkivska H, Tanaka H. Molecular trajectories leading to the alternative fates of duplicate genes. PLoS One 2012; 7:e38958. [PMID: 22720000 PMCID: PMC3375281 DOI: 10.1371/journal.pone.0038958] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 05/14/2012] [Indexed: 11/21/2022] Open
Abstract
Gene duplication generates extra gene copies in which mutations can accumulate without risking the function of pre-existing genes. Such mutations modify duplicates and contribute to evolutionary novelties. However, the vast majority of duplicates appear to be short-lived and experience duplicate silencing within a few million years. Little is known about the molecular mechanisms leading to these alternative fates. Here we delineate differing molecular trajectories of a relatively recent duplication event between humans and chimpanzees by investigating molecular properties of a single duplicate: DNA sequences, gene expression and promoter activities. The inverted duplication of the Glutathione S-transferase Theta 2 (GSTT2) gene had occurred at least 7 million years ago in the common ancestor of African great apes and is preserved in chimpanzees (Pan troglodytes), whereas a deletion polymorphism is prevalent in humans. The alternative fates are associated with expression divergence between these species, and reduced expression in humans is regulated by silencing mutations that have been propagated between duplicates by gene conversion. In contrast, selective constraint preserved duplicate divergence in chimpanzees. The difference in evolutionary processes left a unique DNA footprint in which dying duplicates are significantly more similar to each other (99.4%) than preserved ones. Such molecular trajectories could provide insights for the mechanisms underlying duplicate life and death in extant genomes.
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Affiliation(s)
- Michael Marotta
- Department of Molecular Genetics, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
| | - Helen Piontkivska
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Hisashi Tanaka
- Department of Molecular Genetics, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
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Tong Y, Zheng K, Zhao S, Xiao G, Luo C. Sequence divergence in the 3'-untranslated region has an effect on the subfunctionalization of duplicate genes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2012; 318:531-44. [PMID: 22674856 DOI: 10.1002/jez.b.22457] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 02/01/2012] [Accepted: 04/03/2012] [Indexed: 12/20/2022]
Abstract
Recent studies demonstrated that sequence divergence in both transcriptional regulatory region and coding region contributes to the subfunctionalization of duplicate gene. However, whether sequence divergence in the 3'-untranslated region (3'-UTR) has an impact on the subfunctionalization of duplicate genes remains unclear. Here, we identified two diverging duplicate vsx1 (visual system homeobox-1) loci in goldfish, named vsx1A1 and vsx1A2. Phylogenetic analysis suggests that vsx1A1 and vsx1A2 may arise from a duplication of vsx1 after the separation of goldfish and zebrafish. Sequence comparison revealed that divergence in both transcriptional and translational regulatory regions is higher than divergence in the introns. vsx1A2 expresses during blastula and gastrula stages and in adult retina but silences from segmentation stage to hatching stage, vsx1A1 starts expression from segmentation onward. Comparing to that zebrafish vsx1 expresses in all the developmental stages and in the adult retina, it appears that goldfish vsx1A1 and vsx1A2 are under going to share the functions of ancestral vsx1. The different but overlapping temporal expression patterns of vsx1A1 and vsx1A2 suggest that sequence divergence in the promoter region of duplicate vsx1 is not sufficient for partitioning the functions of ancestral vsx1. By comparing vsx1A1 and vsx1A2 3'-UTR-linked green fluorescent protein gene expression patterns, we demonstrated that the 3'-UTR of vsx1A1 remains but the 3'-UTR of vsx1A2 has lost the capability of mediating bipolar cell specific expression during retina development. These results indicate that sequence divergence in the 3'-UTRs has a clear effect on subfunctionalization of the duplicate genes.
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Affiliation(s)
- Ying Tong
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
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41
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Chen Y, Takano-Maruyama M, Fritzsch B, Gaufo GO. Hoxb1 controls anteroposterior identity of vestibular projection neurons. PLoS One 2012; 7:e34762. [PMID: 22485187 PMCID: PMC3317634 DOI: 10.1371/journal.pone.0034762] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2011] [Accepted: 03/09/2012] [Indexed: 11/18/2022] Open
Abstract
The vestibular nuclear complex (VNC) consists of a collection of sensory relay nuclei that integrates and relays information essential for coordination of eye movements, balance, and posture. Spanning the majority of the hindbrain alar plate, the rhombomere (r) origin and projection pattern of the VNC have been characterized in descriptive works using neuroanatomical tracing. However, neither the molecular identity nor developmental regulation of individual nucleus of the VNC has been determined. To begin to address this issue, we found that Hoxb1 is required for the anterior-posterior (AP) identity of precursors that contribute to the lateral vestibular nucleus (LVN). Using a gene-targeted Hoxb1-GFP reporter in the mouse, we show that the LVN precursors originate exclusively from r4 and project to the spinal cord in the stereotypic pattern of the lateral vestibulospinal tract that provides input into spinal motoneurons driving extensor muscles of the limb. The r4-derived LVN precursors express the transcription factors Phox2a and Lbx1, and the glutamatergic marker Vglut2, which together defines them as dB2 neurons. Loss of Hoxb1 function does not alter the glutamatergic phenotype of dB2 neurons, but alters their stereotyped spinal cord projection. Moreover, at the expense of Phox2a, the glutamatergic determinants Lmx1b and Tlx3 were ectopically expressed by dB2 neurons. Our study suggests that the Hox genes determine the AP identity and diversity of vestibular precursors, including their output target, by coordinating the expression of neurotransmitter determinant and target selection properties along the AP axis.
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Affiliation(s)
- Yiju Chen
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
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42
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Franchini LF, de Souza FS, Low MJ, Rubinstein M. Positive selection of co-opted mobile genetic elements in a mammalian gene: If you can't beat them, join them. Mob Genet Elements 2012; 2:106-109. [PMID: 22934245 PMCID: PMC3429518 DOI: 10.4161/mge.20267] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The proopiomelanocortin (Pomc) gene encodes a prepropeptide with essential functions in the response to stress and energy balance, which is expressed in the pituitary and hypothalamus of vertebrate animals. Neuronal expression of Pomc is controlled by two distal enhancers named nPE1 and nPE2. Using transgenic mice, we observed that both enhancers drive identical expression patterns in the mammalian hypothalamus, starting at embryonic day 10.5, when endogenous Pomc expression commences. This overlapping enhancer activity is maintained throughout hypothalamic development and into adulthood. We also found that nPE1 and nPE2 were exapted as neuronal enhancers into the POMC locus after the sequential insertion of two unrelated retroposons. Thus, nPE1 and nPE2 are functional analogs and represent an authentic first example of convergent molecular evolution of cell-specific transcriptional enhancers. In this Commentary we discuss the following questions that remain unanswered: (1) how does transcriptional control of POMC operate in hypothalamic neurons of non-mammalian vertebrates? (2) What evolutionary forces are maintaining two discrete neuronal POMC enhancers under purifying selection for the last ~100 million years in all placental mammals? (3) What is the contribution of MaLRs to genome evolution?
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Affiliation(s)
- Lucia F. Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Consejo Nacional de Investigaciones Científicas y Técnicas; Buenos Aires, Argentina
| | - Flavio S.J. de Souza
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; Buenos Aires, Argentina
| | - Malcolm J. Low
- Department of Molecular and Integrative Physiology; University of Michigan; Ann Arbor, MI USA
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular; Consejo Nacional de Investigaciones Científicas y Técnicas and Facultad de Ciencias Exactas y Naturales; Universidad de Buenos Aires; Buenos Aires, Argentina
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43
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Abstract
Recent advances in neuroimaging techniques turned possible for neuroradiologists to be frequently the first one to detect possible brain structural anomalies. However, with all the recent advances in genetics and embryology, understanding posterior fossa malformation's principles is being hardest to be achieved than previously. Studies in vertebrate models provide a developmental framework in which to categorize human hindbrain malformations and serve to inform our thinking regarding candidate genes involved in disrupted developmental processes. The main focus of this review was to survey the basic principles of the rhombomere division, anteroposterior and dorsoventral patterning, alar and basal zone concept, and axonal path finding to integrate the knowledge of human hindbrain malformations for better understanding the genetic basis of hindbrain development.
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44
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Erickson T, Pillay LM, Waskiewicz AJ. Zebrafish Tshz3b negatively regulates Hox function in the developing hindbrain. Genesis 2011; 49:725-42. [PMID: 21714061 DOI: 10.1002/dvg.20781] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Revised: 06/13/2011] [Accepted: 06/19/2011] [Indexed: 01/18/2023]
Abstract
In flies, the zinc-finger protein Teashirt promotes trunk segmental identities, in part, by repressing the expression and function of anterior hox paralog group (PG) 1-4 genes that specify head fates. Anterior-posterior patterning of the vertebrate hindbrain also requires Hox PG 1-4 function, but the role of vertebrate teashirt-related genes in this process has not been investigated. In this work, we use overexpression and structure-function analyses to show that zebrafish tshz3b antagonizes Hox-dependent hindbrain segmentation. Ectopic Tshz3b perturbs the specification of rhombomere identities and leads to the caudal expansion of r1, the only rhombomere whose identity is specified independently of Hox function. This overexpression phenotype does not require the homeodomain and C-terminal zinc fingers that are unique to vertebrate Teashirt-related proteins, but does require that Tshz3b function as a repressor. Together, these results argue that the negative regulation of Hox PG 1-4 function is a conserved characteristic of Teashirt-related proteins.
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Affiliation(s)
- Timothy Erickson
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
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Choe SK, Zhang X, Hirsch N, Straubhaar J, Sagerström CG. A screen for hoxb1-regulated genes identifies ppp1r14al as a regulator of the rhombomere 4 Fgf-signaling center. Dev Biol 2011; 358:356-67. [PMID: 21787765 DOI: 10.1016/j.ydbio.2011.05.676] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 05/20/2011] [Accepted: 05/21/2011] [Indexed: 01/21/2023]
Abstract
Segmentation of the vertebrate hindbrain into multiple rhombomeres is essential for proper formation of the cerebellum, cranial nerves and cranial neural crest. Paralog group 1 (PG1) hox genes are expressed early in the caudal hindbrain and are required for rhombomere formation. Accordingly, loss of PG1 hox function disrupts development of caudal rhombomeres in model organisms and causes brainstem defects, associated with cognitive impairment, in humans. In spite of this important role for PG1 hox genes, transcriptional targets of PG1 proteins are not well characterized. Here we use ectopic expression together with embryonic dissection to identify novel targets of the zebrafish PG1 gene hoxb1b. Of 100 genes up-regulated by hoxb1b, 54 were examined and 25 were found to represent novel hoxb1b regulated hindbrain genes. The ppp1r14al gene was analyzed in greater detail and our results indicate that Hoxb1b is likely to directly regulate ppp1r14al expression in rhombomere 4. Furthermore, ppp1r14al is essential for establishment of the earliest hindbrain signaling-center in rhombomere 4 by regulating expression of fgf3.
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Affiliation(s)
- Seong-Kyu Choe
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605-2324, USA
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46
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He X, Yan YL, Eberhart JK, Herpin A, Wagner TU, Schartl M, Postlethwait JH. miR-196 regulates axial patterning and pectoral appendage initiation. Dev Biol 2011; 357:463-77. [PMID: 21787766 DOI: 10.1016/j.ydbio.2011.07.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 07/05/2011] [Accepted: 07/08/2011] [Indexed: 12/18/2022]
Abstract
Vertebrate Hox clusters contain protein-coding genes that regulate body axis development and microRNA (miRNA) genes whose functions are not yet well understood. We overexpressed the Hox cluster microRNA miR-196 in zebrafish embryos and found four specific, viable phenotypes: failure of pectoral fin bud initiation, deletion of the 6th pharyngeal arch, homeotic aberration and loss of rostral vertebrae, and reduced number of ribs and somites. Reciprocally, miR-196 knockdown evoked an extra pharyngeal arch, extra ribs, and extra somites, confirming endogenous roles of miR-196. miR-196 injection altered expression of hox genes and the signaling of retinoic acid through the retinoic acid receptor gene rarab. Knocking down rarab mimicked the pectoral fin phenotype of miR-196 overexpression, and reporter constructs tested in tissue culture and in embryos showed that the rarab 3'UTR is a miR-196 target for pectoral fin bud initiation. These results show that a Hox cluster microRNA modulates development of axial patterning similar to nearby protein-coding Hox genes, and acts on appendicular patterning at least in part by modulating retinoic acid signaling.
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Affiliation(s)
- Xinjun He
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403, USA.
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47
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Mapp OM, Walsh GS, Moens CB, Tada M, Prince VE. Zebrafish Prickle1b mediates facial branchiomotor neuron migration via a farnesylation-dependent nuclear activity. Development 2011; 138:2121-32. [PMID: 21521740 DOI: 10.1242/dev.060442] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The facial branchiomotor neurons (FBMNs) undergo a characteristic tangential migration in the vertebrate hindbrain. We previously used a morpholino knockdown approach to reveal that zebrafish prickle1b (pk1b) is required for this migration. Here we report that FBMN migration is also blocked in a pk1b mutant with a disruption in the consensus farnesylation motif. We confirmed that this lipid modification is required during FBMN migration by disrupting the function of farnesyl biosynthetic enzymes. Furthermore, farnesylation of a tagged Pk1b is required for its nuclear localization. Using a unique rescue approach, we have demonstrated that Pk1b nuclear localization and farnesylation are required during FBMN migration. Our data suggest that Pk1b acts at least partially independently of core planar cell polarity molecules at the plasma membrane, and might instead be acting at the nucleus. We also found that the neuronal transcriptional silencer REST is necessary for FBMN migration, and we provide evidence that interaction between Pk1b and REST is required during this process. Finally, we demonstrate that REST protein, which is normally localized in the nuclei of migrating FBMNs, is depleted from the nuclei of Pk1b-deficient neurons. We conclude that farnesylation-dependent nuclear localization of Pk1b is required to regulate REST localization and thus FBMN migration.
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Affiliation(s)
- Oni M Mapp
- Committee on Developmental Biology, University of Chicago, Chicago, IL 60615, USA
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48
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Chen Y, Takano-Maruyama M, Gaufo GO. Plasticity of neural crest-placode interaction in the developing visceral nervous system. Dev Dyn 2011; 240:1880-8. [PMID: 21674689 DOI: 10.1002/dvdy.22679] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2011] [Indexed: 12/13/2022] Open
Abstract
The reciprocal relationship between rhombomere (r)-derived cranial neural crest (NC) and epibranchial placodal cells derived from the adjacent branchial arch is critical for visceral motor and sensory gangliogenesis, respectively. However, it is unknown whether the positional match between these neurogenic precursors is hard-wired along the anterior-posterior (A/P) axis. Here, we use the interaction between r4-derived NC and epibranchial placode-derived geniculate ganglion as a model to address this issue. In Hoxa1(-/-) b1(-/-) embryos, r2 NC compensates for the loss of r4 NC. Specifically, a population of r2 NC cells is redirected toward the geniculate ganglion, where they differentiate into postganglionic (motor) neurons. Reciprocally, the inward migration of the geniculate ganglion is associated with r2 NC. The ability of NC and placodal cells to, respectively, differentiate and migrate despite a positional mismatch along the A/P axis reflects the plasticity in the relationship between the two neurogenic precursors of the vertebrate head.
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Affiliation(s)
- Yiju Chen
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas 78249, USA
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49
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The transcriptional mediator component Med12 is required for hindbrain boundary formation. PLoS One 2011; 6:e19076. [PMID: 21533047 PMCID: PMC3080914 DOI: 10.1371/journal.pone.0019076] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 03/23/2011] [Indexed: 11/30/2022] Open
Abstract
Background Rhombomere boundaries form during hindbrain segmentation and are critical for maintaining segmental integrity and regulating migration in the hindbrain. Some genetic models affecting hindbrain boundary formation have been described, but involvement of components of the transcriptional mediator complex in boundary formation has not reported so far. Principal Findings The kto/med12 mutant zebrafish, which affects the Mediator component Med12, causes specific loss of rhombomere boundary cells even though segmentation of the hindbrain takes place at least in part. In kto mutant embryos, cells forming rhombomere boundaries were largely absent as indicated by the use of several marker genes. While no obvious increase in cell death was observed, we found a notable reduction of cell proliferation in the hindbrain of kto mutant zebrafish. Conclusions The kto/med12 mutation results in specific defects of boundary cell formation in the zebrafish hindbrain.
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50
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Capellini TD, Zappavigna V, Selleri L. Pbx homeodomain proteins: TALEnted regulators of limb patterning and outgrowth. Dev Dyn 2011; 240:1063-86. [PMID: 21416555 DOI: 10.1002/dvdy.22605] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/13/2011] [Indexed: 12/14/2022] Open
Abstract
Limb development has long provided an excellent model for understanding the genetic principles driving embryogenesis. Studies utilizing chick and mouse have led to new insights into limb patterning and morphogenesis. Recent research has centered on the regulatory networks underlying limb development. Here, we discuss the hierarchical, overlapping, and iterative roles of Pbx family members in appendicular development that have emerged from genetic analyses in the mouse. Pbx genes are essential in determining limb bud positioning, early bud formation, limb axes establishment and coordination, and patterning and morphogenesis of most elements of the limb and girdle. Pbx proteins directly regulate critical effectors of limb and girdle development, including morphogen-encoding genes like Shh in limb posterior mesoderm, and transcription factor-encoding genes like Alx1 in pre-scapular domains. Interestingly, at least in limb buds, Pbx appear to act not only as Hox cofactors, but also in the upstream control of 5' HoxA/D gene expression.
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Affiliation(s)
- Terence D Capellini
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, New York, New York, USA
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