1
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Jurynec MJ, Gavile CM, Honeggar M, Ma Y, Veerabhadraiah SR, Novak KA, Hoshijima K, Kazmers NH, Grunwald DJ. NOD/RIPK2 signalling pathway contributes to osteoarthritis susceptibility. Ann Rheum Dis 2022; 81:1465-1473. [PMID: 35732460 PMCID: PMC9474725 DOI: 10.1136/annrheumdis-2022-222497] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/07/2022] [Indexed: 12/21/2022]
Abstract
OBJECTIVES How inflammatory signalling contributes to osteoarthritis (OA) susceptibility is undetermined. An allele encoding a hyperactive form of the Receptor Interacting Protein Kinase 2 (RIPK2) proinflammatory signalling intermediate has been associated with familial OA. To test whether altered nucleotide-binding oligomerisation domain (NOD)/RIPK2 pathway activity causes heightened OA susceptibility, we investigated whether variants affecting additional pathway components are associated with familial OA. To determine whether the Ripk2104Asp disease allele is sufficient to account for the familial phenotype, we determined the effect of the allele on mice. METHODS Genomic analysis of 150 independent families with dominant inheritance of OA affecting diverse joints was used to identify coding variants that segregated strictly with occurrence of OA. Genome editing was used to introduce the OA-associated RIPK2 (p.Asn104Asp) allele into the genome of inbred mice. The consequences of the Ripk2104Asp disease allele on physiology and OA susceptibility in mice were measured by histology, immunohistochemistry, serum cytokine levels and gene expression. RESULTS We identified six novel variants affecting components of the NOD/RIPK2 inflammatory signalling pathway that are associated with familial OA affecting the hand, shoulder or foot. The Ripk2104Asp allele acts dominantly to alter basal physiology and response to trauma in the mouse knee. Whereas the knees of uninjured Ripk2Asp104 mice appear normal histologically, the joints exhibit a set of marked gene expression changes reminiscent of overt OA. Although the Ripk2104Asp mice lack evidence of chronically elevated systemic inflammation, they do exhibit significantly increased susceptibility to post-traumatic OA (PTOA). CONCLUSIONS Two types of data support the hypothesis that altered NOD/RIPK2 signalling confers susceptibility to OA.
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Affiliation(s)
- Michael J Jurynec
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
- Department of Human Genetics, University of Utah Health, Salt Lake City, Utah, USA
| | - Catherine M Gavile
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - Matthew Honeggar
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - Ying Ma
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | | | - Kendra A Novak
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah Health, Salt Lake City, Utah, USA
| | - Nikolas H Kazmers
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - David J Grunwald
- Department of Human Genetics, University of Utah Health, Salt Lake City, Utah, USA
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2
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Arveseth CD, Happ JT, Hedeen DS, Zhu JF, Capener JL, Klatt Shaw D, Deshpande I, Liang J, Xu J, Stubben SL, Nelson IB, Walker MF, Kawakami K, Inoue A, Krogan NJ, Grunwald DJ, Hüttenhain R, Manglik A, Myers BR. Smoothened transduces Hedgehog signals via activity-dependent sequestration of PKA catalytic subunits. PLoS Biol 2021; 19:e3001191. [PMID: 33886552 PMCID: PMC8096101 DOI: 10.1371/journal.pbio.3001191] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 05/04/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
The Hedgehog (Hh) pathway is essential for organ development, homeostasis, and regeneration. Dysfunction of this cascade drives several cancers. To control expression of pathway target genes, the G protein-coupled receptor (GPCR) Smoothened (SMO) activates glioma-associated (GLI) transcription factors via an unknown mechanism. Here, we show that, rather than conforming to traditional GPCR signaling paradigms, SMO activates GLI by binding and sequestering protein kinase A (PKA) catalytic subunits at the membrane. This sequestration, triggered by GPCR kinase (GRK)-mediated phosphorylation of SMO intracellular domains, prevents PKA from phosphorylating soluble substrates, releasing GLI from PKA-mediated inhibition. Our work provides a mechanism directly linking Hh signal transduction at the membrane to GLI transcription in the nucleus. This process is more fundamentally similar between species than prevailing hypotheses suggest. The mechanism described here may apply broadly to other GPCR- and PKA-containing cascades in diverse areas of biology.
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Affiliation(s)
- Corvin D. Arveseth
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - John T. Happ
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Danielle S. Hedeen
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ju-Fen Zhu
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jacob L. Capener
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Dana Klatt Shaw
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ishan Deshpande
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Jiahao Liang
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Jiewei Xu
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Sara L. Stubben
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Isaac B. Nelson
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Madison F. Walker
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Kouki Kawakami
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Asuka Inoue
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Nevan J. Krogan
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - David J. Grunwald
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Ruth Hüttenhain
- Department of Cellular and Molecular Pharmacology, Quantitative Biosciences Institute, University of California, San Francisco, California, United States of America
- J. David Gladstone Institutes, San Francisco, California, United States of America
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, Department of Anaesthesia and Perioperative Care, University of California, San Francisco, California, United States of America
| | - Benjamin R. Myers
- Department of Oncological Sciences, Department of Biochemistry, Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
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3
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Teerlink CC, Jurynec MJ, Hernandez R, Stevens J, Hughes DC, Brunker CP, Rowe K, Grunwald DJ, Facelli JC, Cannon-Albright LA. A role for the MEGF6 gene in predisposition to osteoporosis. Ann Hum Genet 2021; 85:58-72. [PMID: 33026655 PMCID: PMC8274237 DOI: 10.1111/ahg.12408] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/19/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
Osteoporosis is a common skeletal disorder characterized by deterioration of bone tissue. The set of genetic factors contributing to osteoporosis is not completely specified. High-risk osteoporosis pedigrees were analyzed to identify genes that may confer susceptibility to disease. Candidate predisposition variants were identified initially by whole exome sequencing of affected-relative pairs, approximately cousins, from 10 pedigrees. Variants were filtered on the basis of population frequency, concordance between pairs of cousins, affecting a gene associated with osteoporosis, and likelihood to have functionally damaging, pathogenic consequences. Subsequently, variants were tested for segregation in 68 additional relatives of the index carriers. A rare variant in MEGF6 (rs755467862) showed strong evidence of segregation with the disease phenotype. Predicted protein folding indicated the variant (Cys200Tyr) may disrupt structure of an EGF-like calcium-binding domain of MEGF6. Functional analyses demonstrated that complete loss of the paralogous genes megf6a and megf6b in zebrafish resulted in significant delay of cartilage and bone formation. Segregation analyses, in silico protein structure modeling, and functional assays support a role for MEGF6 in predisposition to osteoporosis.
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Affiliation(s)
- Craig C. Teerlink
- Genetic Epidemiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, 84132, USA
| | - Michael J Jurynec
- Department of Orthopaedics , University of Utah, Salt Lake City, 84108, USA
| | - Rolando Hernandez
- Department of Biomedical Informatics, University of Utah, Salt Lake City, 84108, USA
| | - Jeff Stevens
- Genetic Epidemiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, 84132, USA
| | - Dana C. Hughes
- Genetic Epidemiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, 84132, USA
- Department of Internal Medicine, University of Utah, Salt Lake City, 84132, USA
| | - Cherie P. Brunker
- Department of Internal Medicine, University of Utah, Salt Lake City, 84132, USA
- Intermountain Healthcare, Salt Lake City, UT, 84113, USA
| | - Kerry Rowe
- Intermountain Healthcare, Salt Lake City, UT, 84113, USA
| | - David J. Grunwald
- Department of Human Genetics, University of Utah, Salt Lake City, UT, 84112, USA
| | - Julio C. Facelli
- Department of Biomedical Informatics, University of Utah, Salt Lake City, 84108, USA
| | - Lisa A. Cannon-Albright
- Genetic Epidemiology, Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, 84132, USA
- George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, 84148, USA
- Huntsman Cancer Institute, Salt Lake City, UT, 84112, USA
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4
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Adolfi MC, Herpin A, Martinez-Bengochea A, Kneitz S, Regensburger M, Grunwald DJ, Schartl M. Crosstalk Between Retinoic Acid and Sex-Related Genes Controls Germ Cell Fate and Gametogenesis in Medaka. Front Cell Dev Biol 2021; 8:613497. [PMID: 33537305 PMCID: PMC7848095 DOI: 10.3389/fcell.2020.613497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Sex determination (SD) is a highly diverse and complex mechanism. In vertebrates, one of the first morphological differences between the sexes is the timing of initiation of the first meiosis, where its initiation occurs first in female and later in male. Thus, SD is intimately related to the responsiveness of the germ cells to undergo meiosis in a sex-specific manner. In some vertebrates, it has been reported that the timing for meiosis entry would be under control of retinoic acid (RA), through activation of Stra8. In this study, we used a fish model species for sex determination and lacking the stra8 gene, the Japanese medaka (Oryzias latipes), to investigate the connection between RA and the sex determination pathway. Exogenous RA treatments act as a stress factor inhibiting germ cell differentiation probably by activation of dmrt1a and amh. Disruption of the RA degrading enzyme gene cyp26a1 induced precocious meiosis and oogenesis in embryos/hatchlings of female and even some males. Transcriptome analyzes of cyp26a1–/–adult gonads revealed upregulation of genes related to germ cell differentiation and meiosis, in both ovaries and testes. Our findings show that germ cells respond to RA in a stra8 independent model species. The responsiveness to RA is conferred by sex-related genes, restricting its action to the sex differentiation period in both sexes.
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Affiliation(s)
- Mateus C Adolfi
- University of Wuerzburg, Developmental Biochemistry, Biocenter, Wuerzburg, Germany
| | - Amaury Herpin
- INRA, UR1037, Fish Physiology and Genomics, Rennes, France.,State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Anabel Martinez-Bengochea
- University of Wuerzburg, Developmental Biochemistry, Biocenter, Wuerzburg, Germany.,Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, Brazil
| | - Susanne Kneitz
- University of Wuerzburg, Developmental Biochemistry, Biocenter, Wuerzburg, Germany
| | - Martina Regensburger
- University of Wuerzburg, Developmental Biochemistry, Biocenter, Wuerzburg, Germany
| | - David J Grunwald
- Department of Human Genetics, University of Utah, Salt Lake City, UT, United States
| | - Manfred Schartl
- University of Wuerzburg, Developmental Biochemistry, Biocenter, Wuerzburg, Germany.,University of Wuerzburg, Developmental Biochemistry, Biocenter, Wuerzburg, Germany
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5
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Chagovetz AA, Klatt Shaw D, Ritchie E, Hoshijima K, Grunwald DJ. Interactions among ryanodine receptor isotypes contribute to muscle fiber type development and function. Dis Model Mech 2019; 13:dmm.038844. [PMID: 31383689 PMCID: PMC6906632 DOI: 10.1242/dmm.038844] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
Mutations affecting ryanodine receptor (RyR) calcium release channels commonly underlie congenital myopathies. Although these channels are known principally for their essential roles in muscle contractility, mutations in the human RYR1 gene result in a broad spectrum of phenotypes, including muscle weakness, altered proportions of fiber types, anomalous muscle fibers with cores or centrally placed nuclei, and dysmorphic craniofacial features. Currently, it is unknown which phenotypes directly reflect requirements for RyRs and which result secondarily to aberrant muscle function. To identify biological processes requiring RyR function, skeletal muscle development was analyzed in zebrafish embryos harboring protein-null mutations. RyR channels contribute to both muscle fiber development and function. Loss of some RyRs had modest effects, altering muscle fiber-type specification in the embryo without compromising viability. In addition, each RyR-encoding gene contributed to normal swimming behavior and muscle function. The RyR channels do not function in a simple additive manner. For example, although isoform RyR1a is sufficient for muscle contraction in the absence of RyR1b, RyR1a normally attenuates the activity of the co-expressed RyR1b channel in slow muscle. RyR3 also acts to modify the functions of other RyR channels. Furthermore, diminished RyR-dependent contractility affects both muscle fiber maturation and craniofacial development. These findings help to explain some of the heterogeneity of phenotypes that accompany RyR1 mutations in humans.
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Affiliation(s)
- Alexis A Chagovetz
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Dana Klatt Shaw
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Erin Ritchie
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
| | - David J Grunwald
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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6
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Morrow ZT, Maxwell AM, Hoshijima K, Talbot JC, Grunwald DJ, Amacher SL. tbx6l and tbx16 are redundantly required for posterior paraxial mesoderm formation during zebrafish embryogenesis. Dev Dyn 2017; 246:759-769. [PMID: 28691257 DOI: 10.1002/dvdy.24547] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 05/19/2017] [Accepted: 07/04/2017] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND T-box genes encode a large transcription factor family implicated in many aspects of development. We are focusing on two related zebrafish T-box genes, tbx6l and tbx16, that are expressed in highly overlapping patterns in embryonic paraxial mesoderm. tbx16 mutants are deficient in trunk, but not tail, somites; we explored whether presence of tail somites in tbx16 mutants was due to compensatory function provided by the tbx6l gene. RESULTS We generated two zebrafish tbx6l mutant alleles. Loss of tbx6l has no apparent effect on embryonic development, nor does tbx6l loss enhance the phenotype of two other T-box gene mutants, ta and tbx6, or of the mesp family gene mutant msgn1. In contrast, loss of tbx6l function dramatically enhances the paraxial mesoderm deficiency of tbx16 mutants. CONCLUSIONS These data demonstrate that tbx6l and tbx16 genes function redundantly to direct tail somite development. tbx6l single mutants develop normally because tbx16 fully compensates for loss of tbx6l function. However, tbx6l only partially compensates for loss of tbx16 function. These results resolve the question of why loss of function of tbx16 gene, which is expressed throughout the ventral and paraxial mesoderm, profoundly affects somite development in the trunk but not the tail. Developmental Dynamics 246:759-769, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Zachary T Morrow
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio
| | - Adrienne M Maxwell
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Jared C Talbot
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio.,Department of Biological Chemistry and Pharmacology, The Ohio State University School of Medicine, Columbus, Ohio.,Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, Ohio
| | - David J Grunwald
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Sharon L Amacher
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio.,Department of Biological Chemistry and Pharmacology, The Ohio State University School of Medicine, Columbus, Ohio.,Center for Muscle Health and Neuromuscular Disorders, The Ohio State University and Nationwide Children's Hospital, Columbus, Ohio.,Center for RNA Biology, The Ohio State University, Columbus, Ohio
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7
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Abstract
Simple and efficient methods are presented for creating precise modifications of the zebrafish genome. Edited alleles are generated by homologous recombination between the host genome and double-stranded DNA (dsDNA) donor molecules, stimulated by the induction of double-strand breaks at targeted loci in the host genome. Because several kilobase-long tracts of sequence can be exchanged, multiple genome modifications can be generated simultaneously at a single locus. Methods are described for creating: (1) alleles with simple sequence changes or in-frame additions, (2) knockin/knockout alleles that express a reporter protein from an endogenous locus, and (3) conditional alleles in which exons are flanked by recombinogenic loxP sites. Significantly, our approach to genome editing allows the incorporation of a linked reporter gene into the donor sequences so that successfully edited alleles can be identified by virtue of expression of the reporter. Factors affecting the efficiency of genome editing are discussed, including the finding that dsDNA products of I-SceI meganuclease enzyme digestion are particularly effective as donor molecules for gene-editing events. Reagents and procedures are described for accomplishing efficient genome editing in the zebrafish.
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Affiliation(s)
- K Hoshijima
- University of Utah, Salt Lake City, UT, United States
| | - M J Jurynec
- University of Utah, Salt Lake City, UT, United States
| | - D J Grunwald
- University of Utah, Salt Lake City, UT, United States
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8
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Ota S, Hisano Y, Muraki M, Hoshijima K, Dahlem TJ, Grunwald DJ, Okada Y, Kawahara A. Efficient identification of TALEN-mediated genome modifications using heteroduplex mobility assays. Genes Cells 2013; 18:450-8. [PMID: 23573916 DOI: 10.1111/gtc.12050] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 02/18/2013] [Indexed: 01/24/2023]
Abstract
The heteroduplex mobility assay (HMA) is widely used to characterize strain variants of human viruses. To determine whether it can detect small sequence differences in homologous templates, we constructed a series of deletion constructs (1-10 bp deletions) in the multiple cloning site (MCS) of pBluescript II. After PCR amplification of the MCS using a mixture of wild-type and one of the deletion constructs, the resulting PCR amplicons were electrophoresed using 15% polyacrylamide gels. Two types of heteroduplexes exhibited retarded electrophoretic migration compared with individual homoduplexes. Therefore, we applied this HMA to detect transcription activator-like effector nucleases (TALEN)-induced insertion and/or deletion (indel) mutations at an endogenous locus. We found that TALEN in vivo activity was easily estimated by the degree of multiple HMA profiles derived from TALEN-injected F0 embryos. Furthermore, TALEN-injected F0 founder fish produced several unique HMA profiles in F1 embryos. Sequence analysis confirmed that the different HMA profiles contained distinct indel mutations. Thus, HMA is a rapid and sensitive analytical method for the detection of the TALEN-mediated genome modifications.
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Affiliation(s)
- Satoshi Ota
- Laboratory for Cardiovascular Molecular Dynamics, Quantitative Biology Center, RIKEN, Furuedai 6-2-3, Suita, Osaka 565-0874, Japan
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9
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Wang X, Kopinke D, Lin J, McPherson AD, Duncan RN, Otsuna H, Moro E, Hoshijima K, Grunwald DJ, Argenton F, Chien CB, Murtaugh LC, Dorsky RI. Wnt signaling regulates postembryonic hypothalamic progenitor differentiation. Dev Cell 2013; 23:624-36. [PMID: 22975330 DOI: 10.1016/j.devcel.2012.07.012] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 05/15/2012] [Accepted: 07/17/2012] [Indexed: 12/21/2022]
Abstract
Previous studies have raised the possibility that Wnt signaling may regulate both neural progenitor maintenance and neuronal differentiation within a single population. Here we investigate the role of Wnt/β-catenin activity in the zebrafish hypothalamus and find that the pathway is first required for the proliferation of unspecified hypothalamic progenitors in the embryo. At later stages, including adulthood, sequential activation and inhibition of Wnt activity is required for the differentiation of neural progenitors and negatively regulates radial glia differentiation. The presence of Wnt activity is conserved in hypothalamic progenitors of the adult mouse, where it plays a conserved role in inhibiting the differentiation of radial glia. This study establishes the vertebrate hypothalamus as a model for Wnt-regulated postembryonic neural progenitor differentiation and defines specific roles for Wnt signaling in neurogenesis.
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Affiliation(s)
- Xu Wang
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84112, USA
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10
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Xing L, Hoshijima K, Grunwald DJ, Fujimoto E, Quist TS, Sneddon J, Chien CB, Stevenson TJ, Bonkowsky JL. Zebrafish foxP2 zinc finger nuclease mutant has normal axon pathfinding. PLoS One 2012; 7:e43968. [PMID: 22937139 PMCID: PMC3427223 DOI: 10.1371/journal.pone.0043968] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2011] [Accepted: 07/30/2012] [Indexed: 11/18/2022] Open
Abstract
foxP2, a forkhead-domain transcription factor, is critical for speech and language development in humans, but its role in the establishment of CNS connectivity is unclear. While in vitro studies have identified axon guidance molecules as targets of foxP2 regulation, and cell culture assays suggest a role for foxP2 in neurite outgrowth, in vivo studies have been lacking regarding a role for foxP2 in axon pathfinding. We used a modified zinc finger nuclease methodology to generate mutations in the zebrafish foxP2 gene. Using PCR-based high resolution melt curve analysis (HRMA) of G0 founder animals, we screened and identified three mutants carrying nonsense mutations in the 2(nd) coding exon: a 17 base-pair (bp) deletion, an 8bp deletion, and a 4bp insertion. Sequence analysis of cDNA confirmed that these were frameshift mutations with predicted early protein truncations. Homozygous mutant fish were viable and fertile, with unchanged body morphology, and no apparent differences in CNS apoptosis, proliferation, or patterning at embryonic stages. There was a reduction in expression of the known foxP2 target gene cntnap2 that was rescued by injection of wild-type foxP2 transcript. When we examined axon pathfinding using a pan-axonal marker or transgenic lines, including a foxP2-neuron-specific enhancer, we did not observe any axon guidance errors. Our findings suggest that foxP2 is not necessary for axon pathfinding during development.
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Affiliation(s)
- Lingyan Xing
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Interdepartmental Program in Neurosciences, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - David J. Grunwald
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Esther Fujimoto
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Tyler S. Quist
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jacob Sneddon
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Chi-Bin Chien
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Interdepartmental Program in Neurosciences, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Tamara J. Stevenson
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Joshua L. Bonkowsky
- Division of Pediatric Neurology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Interdepartmental Program in Neurosciences, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
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11
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Wythe JD, Jurynec MJ, Urness LD, Jones CA, Sabeh MK, Werdich AA, Sato M, Yost HJ, Grunwald DJ, Macrae CA, Li DY. Hadp1, a newly identified pleckstrin homology domain protein, is required for cardiac contractility in zebrafish. Dis Model Mech 2011; 4:607-21. [PMID: 21628396 PMCID: PMC3180224 DOI: 10.1242/dmm.002204] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The vertebrate heart is one of the first organs to form, and its early function and morphogenesis are crucial for continued embryonic development. Here we analyze the effects of loss of Heart adaptor protein 1 (Hadp1), which we show is required for normal function and morphogenesis of the embryonic zebrafish heart. Hadp1 is a pleckstrin homology (PH)-domain-containing protein whose expression is enriched in embryonic cardiomyocytes. Knockdown of hadp1 in zebrafish embryos reduced cardiac contractility and altered late myocyte differentiation. By using optical mapping and submaximal levels of hadp1 knockdown, we observed profound effects on Ca2+ handling and on action potential duration in the absence of morphological defects, suggesting that Hadp1 plays a major role in the regulation of intracellular Ca2+ handling in the heart. Hadp1 interacts with phosphatidylinositol 4-phosphate [PI4P; also known as PtdIns(4)P] derivatives via its PH domain, and its subcellular localization is dependent upon this motif. Pharmacological blockade of the synthesis of PI4P derivatives in vivo phenocopied the loss of hadp1 in zebrafish. Collectively, these results demonstrate that hadp1 is required for normal cardiac function and morphogenesis during embryogenesis, and suggest that hadp1 modulates Ca2+ handling in the heart through its interaction with phosphatidylinositols.
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Affiliation(s)
- Joshua D Wythe
- Department of Oncological Sciences and Medicine, University of Utah, Salt Lake City, UT 84112, USA
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12
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Vasquez SX, Hansen MS, Bahadur AN, Hockin MF, Kindlmann GL, Nevell L, Wu IQ, Grunwald DJ, Weinstein DM, Jones GM, Johnson CR, Vandeberg JL, Capecchi MR, Keller C. Optimization of volumetric computed tomography for skeletal analysis of model genetic organisms. Anat Rec (Hoboken) 2008; 291:475-87. [PMID: 18286615 DOI: 10.1002/ar.20670] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Forward and reverse genetics now allow researchers to understand embryonic and postnatal gene function in a broad range of species. Although some genetic mutations cause obvious morphological change, other mutations can be more subtle and, without adequate observation and quantification, might be overlooked. For the increasing number of genetic model organisms examined by the growing field of phenomics, standardized but sensitive methods for quantitative analysis need to be incorporated into routine practice to effectively acquire and analyze ever-increasing quantities of phenotypic data. In this study, we present platform-independent parameters for the use of microscopic x-ray computed tomography (microCT) for phenotyping species-specific skeletal morphology of a variety of different genetic model organisms. We show that microCT is suitable for phenotypic characterization for prenatal and postnatal specimens across multiple species.
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Affiliation(s)
- Sergio X Vasquez
- Greehey Children's Cancer Research Institute, The University of Texas Health Science Center San Antonio, San Antonio, Texas 78229, USA
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13
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Lamason RL, Mohideen MAPK, Mest JR, Wong AC, Norton HL, Aros MC, Jurynec MJ, Mao X, Humphreville VR, Humbert JE, Sinha S, Moore JL, Jagadeeswaran P, Zhao W, Ning G, Makalowska I, McKeigue PM, O'donnell D, Kittles R, Parra EJ, Mangini NJ, Grunwald DJ, Shriver MD, Canfield VA, Cheng KC. SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans. Science 2006; 310:1782-6. [PMID: 16357253 DOI: 10.1126/science.1116238] [Citation(s) in RCA: 725] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Lighter variations of pigmentation in humans are associated with diminished number, size, and density of melanosomes, the pigmented organelles of melanocytes. Here we show that zebrafish golden mutants share these melanosomal changes and that golden encodes a putative cation exchanger slc24a5 (nckx5) that localizes to an intracellular membrane, likely the melanosome or its precursor. The human ortholog is highly similar in sequence and functional in zebrafish. The evolutionarily conserved ancestral allele of a human coding polymorphism predominates in African and East Asian populations. In contrast, the variant allele is nearly fixed in European populations, is associated with a substantial reduction in regional heterozygosity, and correlates with lighter skin pigmentation in admixed populations, suggesting a key role for the SLC24A5 gene in human pigmentation.
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Affiliation(s)
- Rebecca L Lamason
- Jake Gittlen Cancer Research Foundation, Department of Pathology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
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14
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Abstract
Transcription factors of the TCF/LEF family interact with the Wnt signaling pathway to control transcription of downstream genes (Clevers, H., van de Wetering, M., 1997. TCF/LEF factor earn their wings. Trends Genet. 13, 485-489). We were interested in cloning family members which were expressed in zebrafish neural crest, because Wnt signaling modulates specification of neural crest fate (Dorsky, R.I., Moon, R.T., Raible, D.W., 1998. Control of neural crest cell fate by the Wnt signalling pathway. Nature 396, 370-373). We cloned a zebrafish homolog of lef1 and localized its chromosomal position by radiation hybrid mapping. lef1 is expressed in the neural crest as well as the tailbud and developing mesoderm, and is maternally expressed in zebrafish, unlike mouse and Xenopus homologs. In addition, we cloned two tcf3 genes and a homolog of tcf4, neither of which were strongly expressed in premigratory neural crest.
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Affiliation(s)
- R I Dorsky
- HHMI and Department of Pharmacology, University of Washington, Seattle, WA 98195, USA.
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15
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Abstract
alyronz12 (aln) is a recessive lethal mutation that affects early stages of neural crest development in the zebrafish. alyron appears to be an insertional mutation as the mutation was generated following microinjection of plasmid DNA into one-cell embryos and the stably integrated transgenic sequences are closely linked to the mutation. The insertion site harbors multiple copies of the plasmid sequence that have experienced complex rearrangements. Host-insert junction fragments have been molecularly cloned and host sequences adjacent to the transgene have been used to map the mutation to the distal arm of linkage group 15. alyron function is required cell-autonomously in the neural crest lineage. alyron mutants have a severe but not complete deficit of premigratory neural crest as judged by reduced expression of several markers associated with early stages of neural crest development. Lack of premigratory neural crest is likely to account for the two most conspicuous characteristics of alyron mutants: the absence of body pigmentation and the inability to affect blood circulation. The neural crest phenotype of alyron mutants resembles that observed in mouse mutants that lack Pax-3 or both Wnt-1 and Wnt-3a function, and expression of the zebrafish homologues of these genes is greatly reduced in the dorsal neural keels of alyron mutants. In contrast, ventral neural keel identity appears unaffected. Given our findings that the mutation is unlinked to pax or wnt genes that have been described in the zebrafish, we propose that alyron is a novel gene function required for the specification and/or proliferative expansion of neural crest progenitors.
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Affiliation(s)
- C J Cretekos
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, 84112, USA
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16
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Abstract
BACKGROUND Fate mapping studies have shown that progenitor cells of three vertebrate embryonic midline structures - the floorplate in the ventral neural tube, the notochord and the dorsal endoderm - occupy a common region prior to gastrulation. This common region of origin raises the possibility that interactions between midline progenitor cells are important for their specification prior to germ layer formation. RESULTS One of four known zebrafish homologues of the Drosophila melanogaster cell-cell signaling gene Delta, deltaA (dlA), is expressed in the developing midline, where progenitor cells of the ectodermal floorplate, mesodermal notochord and dorsal endoderm lie close together before they occupy different germ layers. We used a reverse genetic strategy to isolate a missense mutation of dlA, dlAdx2, which coordinately disrupts the development of floorplate, notochord and dorsal endoderm. The dlAdx2 mutant embryos had reduced numbers of floorplate and hypochord cells; these cells lie above and beneath the notochord, respectively. In addition, mutant embryos had excess notochord cells. Expression of a dominant-negative form of Delta protein driven by mRNA microinjection produced a similar effect. In contrast, overexpression of dlA had the opposite effect: fewer trunk notochord cells and excess floorplate and hypochord cells. CONCLUSION Our results indicate that Delta signaling is important for the specification of midline cells. The results are most consistent with the hypothesis that developmentally equivalent midline progenitor cells require Delta-mediated signaling prior to germ layer formation in order to be specified as floorplate, notochord or hypochord.
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Affiliation(s)
- B Appel
- Institute of Neuroscience, 1254 University of Oregon, Eugene, Oregon 97403, USA.
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17
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18
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Bisgrove BW, Raible DW, Walter V, Eisen JS, Grunwald DJ. Expression of c-ret in the zebrafish embryo: potential roles in motoneuronal development. J Neurobiol 1997; 33:749-68. [PMID: 9369149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have isolated and characterized the zebrafish ortholog of c-ret, a gene essential for renal organogenesis and enteric nervous system development in mammals. During zebrafish embryogenesis c-ret transcripts are expressed in a number of tissues including spinal motoneurons, pronephric ducts, cranial ganglia, pharyngeal arches, and the enteric nervous system. We have examined in detail the expression of c-ret during the development of identified spinal primary motoneurons. c-ret expression is regulated in a cell type-specific manner among the three primary motoneurons. c-ret is expressed at its highest levels in caudal primary (CaP) motoneurons and transcripts can be detected shortly before the expression of the CaP-specific gene, islet2. We suggest that c-ret may play a role in specifying CaP cell identity. c-ret is expressed at low levels in the other primary motoneurons and also in a subset of secondary motoneurons, suggesting that it may also play a broader role in motoneuronal survival or maintenance.
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Affiliation(s)
- B W Bisgrove
- Department of Human Genetics, University of Utah, Salt Lake City 84112, USA
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19
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Abstract
Classical embryology experiments have indicated the existence of dorsal-type and ventral-type mesoderms that arise as a consequence of mesoderm induction during vertebrate development. Here we report that the zebrafish tbx6 gene, a member of the Brachyury-related T-box family of genes, is exclusively expressed by ventral mesendoderm. Three observations link the expression of tbx6 to ventral mesoderm specification. First, the gene is initially expressed at the onset of gastrulation within a ventrolateral subpopulation of cells that express the pan-mesodermal gene, no tail (Brachyury). Second, the mesoderm-inducing factors activin and bFGF activate tbx6 expression in animal caps. Third, dorsalization of the mesendodermal precursor population following exposure of embryos to lithium ions causes down-regulation of tbx6 transcription. tbx6 is expressed transiently in the involuting derivatives of the ventral mesendoderm, which give rise to nonaxial mesodermal tissues; its expression is extinguished as tissue differentiation progresses. Transcription of tbx6 commences about an hour after initiation of expression of the pan-mesendodermal gene no tail and the organizer gene goosecoid. The dependence of tbx6 expression on no tail activity was examined in no tail mutant embryos. The activation of tbx6 transcription in ventral mesoderm does not depend on no tail gene activity. However, no tail appears to contribute to the maintenance of normal levels of tbx6 transcription and may be required for tbx6 transcription in the developing tail.
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Affiliation(s)
- B Hug
- Department of Human Genetics, University of Utah, Salt Lake City 84112, USA
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20
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Liao W, Bisgrove BW, Sawyer H, Hug B, Bell B, Peters K, Grunwald DJ, Stainier DY. The zebrafish gene cloche acts upstream of a flk-1 homologue to regulate endothelial cell differentiation. Development 1997; 124:381-9. [PMID: 9053314 DOI: 10.1242/dev.124.2.381] [Citation(s) in RCA: 221] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The zebrafish cloche mutation affects both the endothelial and hematopoietic lineages at a very early stage (Stainier, D. Y. R., Weinstein, B. M., Detrich, H. W., Zon, L. I. and Fishman, M. C. (1995). Development 121, 3141–3150). The most striking vascular phenotype is the absence of endocardial cells from the heart. Microscopic examination of mutant embryos reveals the presence of endothelial-like cells in the lower trunk and tail regions while head vessels appear to be missing, indicating a molecular diversification of the endothelial lineage. Cell transplantation experiments show that cloche acts cell-autonomously within the endothelial lineage. To analyze further the role of cloche in regulating endothelial cell differentiation, we have examined the expression of flk-1 and tie, two receptor tyrosine kinase genes expressed early and sequentially in the endothelial lineage. In wild-type fish, flk-1-positive cells are found throughout the embryo and differentiate to form the nascent vasculature. In cloche mutants, flk-1-positive cells are found only in the lower trunk and tail regions, and this expression is delayed as compared to wild-type. Unlike the flk-1-positive cells in wild-type embryos, those in cloche mutants do not go on to express tie, suggesting that their differentiation is halted at an early stage. We also find that the cloche mutation is not linked to flk-1. These data indicate that cloche affects the differentiation of all endothelial cells and that it acts at a very early stage, either by directly regulating flk-1 expression or by controlling the differentiation of cells that normally develop to express flk-1. cloche mutants also have a blood deficit and their hematopoietic tissues show no expression of the hematopoietic transcription factor genes GATA-1 or GATA-2 at early stages. Because the appearance of distinct levels of flk-1 expression is delayed in cloche mutants, we examined GATA-1 expression at late embryonic stages and found some blood cell differentiation that appears to be limited to the region lined by the flk-1-expressing cells. The spatial restriction of blood in the ventroposterior-most region of cloche mutant embryos may be indicative of a ventral source of signal(s) controlling hematopoietic differentiation. In addition, the restricted colocalization of blood and endothelium in cloche mutants suggests that important interactions occur between these two lineages during normal development.
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Affiliation(s)
- W Liao
- Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0554, USA
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21
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Affiliation(s)
- D J Grunwald
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City 84112, USA
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22
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Abstract
Zebrafish holds great potential as a model system for studying inner ear development because genetic techniques are highly efficient and inner ear development is a conspicuous and manipulable feature of zebrafish embryogenesis. Here we describe analysis of a semilethal dominant mutation, termed monolith (mnl), that specifically perturbs formation of the anterior (utricular) otolith in the developing ear. Other than the utricular otolith deficiency, all structures in the ear appear morphologically normal in mutant embryos, including posterior otoliths and all sensory epithelia. Expression patterns of several ear marker genes (msxC, msxD, and dlx3) also appear normal in the mutant. To identify the cell type(s) affected by the mnl mutation, chimeras were generated by transplanting dye-labeled +/+ cells into unlabeled mnl/mnl host embryos. Roughly half of such chimeras formed utricular otoliths normally, indicating that the transplanted wild-type cells rescued their mutant hosts. Detailed analysis of +/+ cell fates revealed that virtually all chimeras in which +/+ cells formed support cells in the utricular sensory epithelium were rescued. In contrast, wild-type cells forming other cell types (such as hair cells) or colonizing other regions of the host were not sufficient to facilitate rescue. These data indicate that support cells are required for normal otolith formation, providing the first experimentally established role for support cells in vertebrate sensory epithelia. The data also provide the first clear indication that otolith formation is controlled independently in different regions of the ear by localized cellular functions.
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Affiliation(s)
- B B Riley
- Department of Biology, Texas A&M University, College Station 77843-3258, USA.
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23
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Weinberg ES, Allende ML, Kelly CS, Abdelhamid A, Murakami T, Andermann P, Doerre OG, Grunwald DJ, Riggleman B. Developmental regulation of zebrafish MyoD in wild-type, no tail and spadetail embryos. Development 1996; 122:271-80. [PMID: 8565839 DOI: 10.1242/dev.122.1.271] [Citation(s) in RCA: 471] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We describe the isolation of the zebrafish MyoD gene and its expression in wild-type embryos and in two mutants with altered somite development, no tail (ntl) and spadetail (spt). In the wild-type embryo, MyoD expression first occurs in an early phase, extending from mid-gastrula to just prior to somite formation, in which cells directly adjacent to the axial mesoderm express the gene. In subsequent phases, during the anterior-to-posterior wave of somite formation and maturation, expression occurs within particular regions of each somite. In spt embryos, which lack normal paraxial mesoderm due to incorrect cell migration, early MyoD expression is not observed and transcripts are instead first detected in small groups of trunk cells that will develop into aberrant myotomal-like structures. In ntl embryos, which lack notochords and tails, the early phase of MyoD expression is also absent. However, the later phase of expression within the developing somites appears to occur at the normal time in the ntl mutants, indicating that the presomitogenesis and somitogenesis phases of MyoD expression can be uncoupled. In addition, we demonstrate that the entire paraxial mesoderm of wild-type embryos has the potential to express MyoD when Sonic hedgehog is expressed ubiquitously in the embryo, and that this potential is lost in some of the cells of the paraxial mesoderm lineage in no tail and spadetail embryos. We also show that MyoD expression precedes myogenin expression and follows or is coincident with expression of snaill in some regions that express this gene.
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Affiliation(s)
- E S Weinberg
- Department of Biology, University of Pennsylvania, Philadelphia 19104, USA
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24
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Abstract
A technique is described that greatly increases the efficiency of recovering specific locus point mutations in zebrafish (Danio rerio). Founder individuals that were mosaic for point mutations were produced by mutagenizing postmeiotic gametes with the alkylating agent N-ethyl-N-nitrosourea. Under optimal conditions, each founder carried an average of 10 mutations affecting genes required for embryogenesis. Moreover, approximately 2% of these founders transmitted new mutations at any prespecified pigmentation locus. Analyses of new pigmentation mutations confirmed that most were likely to be point mutations. Thus, mutagenesis of postmeiotic gametes with N-ethyl-N-nitrosourea yielded frequencies of point mutations at specific loci that were 10- to 15-fold higher than previously achieved in zebrafish. Our procedure should, therefore, greatly facilitate recovery of multiple mutant alleles at any locus of interest.
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Affiliation(s)
- B B Riley
- Department of Human Genetics, University of Utah, Salt Lake City 84112, USA
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25
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Abstract
Previously, a tissue-specific fate map was compiled for the gastrula stage of the zebrafish embryo, indicating that development subsequent to this stage follows a reproducible pattern. Here it is shown that each early zebrafish blastomere normally contributes to a subset of the gastrula and thus gives rise to a limited array of tissues. However, the final contribution that any early blastomere makes to the fate map in the gastrula cannot be predicted because of variability in both the position of the future dorsoventral axis with respect to the early cleavage blastomeres and the scattering of daughter cells as the gastrula is formed. Therefore, early cell divisions of the zebrafish embryo cannot reproducibly segregate determinants of tissue fates.
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Affiliation(s)
- K A Helde
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City 84112
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26
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Abstract
It is not known how region- or tissue-specific differences are generated in the zebrafish embryo. To look at the potential role of maternal transcripts in generating cell diversity, we have isolated and characterized the zebrafish homologue of Xenopus DVR-1 (Vg1), a maternally supplied RNA that encodes a member of the transforming growth factor-beta superfamily. The zebrafish DVR-1 RNA is maternally supplied and its protein product shares a high degree of sequence identity with Xenopus DVR-1. These conserved features indicate that DVR-1 is likely to have an essential function in early embryogenesis. However, unlike the frog transcript, which is restricted to vegetal cells, DVR-1 RNA is distributed equally among all zebrafish blastomeres. We suggest that the ubiquitous distribution of DVR-1 RNA reflects a significant aspect of the developmental strategy of the zebrafish in which each blastomere retains an equivalent developmental potential throughout the cleavage period.
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Affiliation(s)
- K A Helde
- Department of Human Genetics, Eccles Institute of Human Genetics, University of Utah, Salt Lake City 84112
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27
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Abstract
A recent paper has challenged the prevailing view that zebrafish blastomeres undergo extensive cell mixing and are unrestricted in their cell fates during early development. Here, we offer a model that resolves apparent contradictions between studies that have examined the origins of cell fate in the zebrafish embryo. The model reconsiders cell movements during epiboly, and how cell mixing, or the lack of it, can affect the predictability of cell fate.
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Affiliation(s)
- E T Wilson
- Department of Human Genetics, Eccles Institute of Genetics, University of Utah, Salt Lake City 84112
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28
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Stachel SE, Grunwald DJ, Myers PZ. Lithium perturbation and goosecoid expression identify a dorsal specification pathway in the pregastrula zebrafish. Development 1993; 117:1261-74. [PMID: 8104775 DOI: 10.1242/dev.117.4.1261] [Citation(s) in RCA: 347] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The zebrafish dorsoventral axis can first be distinguished at gastrulation, upon formation of the embryonic shield, the site of the organizer. We have asked whether the shield is specified before gastrulation. First, we show that brief exposure of premidblastula embryos to lithium, which is known to shut down the phospho-inositol signaling pathway, produces excessive shield formation and extreme hyper-dorsal development. Second, we show that the zebrafish goosecoid homeobox gene is activated at or just after the midblastula in a localized domain of cells that subsequently populate the most anterior region of the incipient shield and axial hypoblast, goosecoid expression is elevated and radialized by early lithium treatment, suggesting that goosecoid plays a role in establishing the organizer and shield. Our results demonstrate that the zebrafish dorsal axis is signaled by a pathway initiated in the cleavage-stage embryo. Furthermore, they provide novel insights into anterior morphogenesis.
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Affiliation(s)
- S E Stachel
- Department of Human Genetics, University of Utah, Salt Lake City 84112
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29
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Abstract
Recessive lethal mutations and mutations at the gol-1 locus were induced in the zebrafish by exposure of mature sperm to the alkylating agent ethyl nitrosourea (ENU). Embryonic lethal phenotypes were recognized among the parthenogenetic progeny of mutagenized animals or among the progeny of daughters of mutagenized animals. Novel specific locus mutations were identified by the failure of mutagenized chromosomes to complement pre-existing mutant alleles at the gol-1 locus. Each mutagenized individual harboured approximately 10 embryonic lethal mutations in its germ line and about 1 in 500 mutagenized animals harboured a new mutation at the gol-1 locus. Three lines of evidence indicate that the majority of mutations that were recovered following treatment of mature sperm with ENU were probably point mutations. First, the soma and germ lines of mutagenized animals were mosaic, as expected following simple alkylation of sperm DNA. Second, mutations induced by ENU at the gol-1 locus affected pigmentation but not viability, unlike the majority of mutations induced at this locus with gamma-irradiation. Third, the ratio of specific locus:recessive lethal mutations induced by ENU was approximately 50-fold lower than the ratio observed following mutagenesis with gamma-rays. Comparison of the incidence with which embryonic recessive lethal mutations were induced with the incidence with which specific locus mutations arose indicates that there are greater than 5000 genes essential to the development and viability of the zebrafish embryo.
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Affiliation(s)
- D J Grunwald
- Institute of Molecular Biology, University of Oregon, Eugene 97403
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30
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Abstract
Recessive lethal germline and specific locus somatic mutations were induced efficiently in the zebrafish by exposure of mature sperm to UV light. Mutagenesis of sperm yielded mosaic individuals: clones bearing novel mutations represented approximately 12-25% of the haploid germ cells and 25-50% of the somatic tissue. Simple methods are described for the reliable identification and propagation of newly arising developmental mutations in zebrafish.
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Affiliation(s)
- D J Grunwald
- Institute of Molecular Biology, University of Oregon, Eugene 97403
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31
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Abstract
Mosaic analysis has been used to study the clonal basis of the development of the pigmented retina of the zebrafish, Brachydanio rerio. Zebrafish embryos heterozygous for a recessive mutation at the gol-1 locus were exposed to gamma-irradiation at various developmental stages to create mosaic individuals consisting of wild-type pigmented cells and a clone of pigmentless (golden) cells in the eye. The contribution of individual embryonic cells to the pigmented retina was measured and the total number of cells in the embryo that contributed descendants to this tissue was determined. Until the 32-cell stage, almost every blastomere has some descendants that participate in the formation of the pigmented retina of the zebrafish. During subsequent cell divisions, up to the several thousand-cell stage, the number of ancestral cells is constant: approximately 40 cells are present that will give rise to progeny in the pigmented retina. Analysis of the size of clones in the pigmented retina indicates that the cells of this tissue do not arise through a rigid series of cell divisions originating in the early embryo. The findings that each cleavage stage cell contributes to the pigmented retina and yet the contribution of such cells is highly variable are consistent with the interpretation that clonal descendants of different blastomeres normally intermix extensively prior to formation of the pigmented retina.
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Affiliation(s)
- G Streisinger
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City 84132
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32
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Abstract
We describe an embryonic lethal mutation in the zebrafish Brachydanio rerio that specifically affects the viability of most cells in the embryonic central nervous system (CNS). The mutation ned-1 (b39rl) was induced with gamma-irradiation and segregates as a single recessive allele closely linked to its centromere. It produces massive cell death in the CNS but a small set of specific neurons, including Rohon-Beard sensory neurons, large hindbrain interneurons, and primary motoneurons, survive embryogenesis and are functional. Synaptic connections between embryonic motoneurons and muscle cells appear physiologically normal, and the normally observed spontaneous flexions are present. Correlated with the presence of sensory neurons and interneurons, mutant embryos display reflexive movements in response to mechanical stimulation. Together, the surviving neurons, called primary neurons, form a class of cells that are prominent in size and arise early during development. Thus, this mutation may define a function that is differentially required by developmentally distinguishable sets of cells in the embryonic CNS.
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Affiliation(s)
- D J Grunwald
- Institute of Molecular Biology, University of Oregon, Eugene 97403
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33
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Abstract
Examination of syngeneic tumor regressor sera prepared by immunization of mice with several different lymphomas revealed a common pattern of reactivity to proteins expressed in these tumors. Antibodies present in these sera immunoprecipitate a triplet of proteins of 115,000 mol wt (p115), 80,000 mol wt (p80), and 32,000 mol wt (p32) from many but not all T cell lymphomas of mice. P80, the predominant molecular species immunoprecipitated with these sera, is a nonglycosylated, phosphoprotein that does not appear to be expressed at the cell surface. Comparison of the tryptic peptides of p32 and p80 indicated that the peptides found in p32 are a subset of those found in p80. Comparison of the tryptic peptides of p80 with those of the p120 gag-fusion protein of Abelson murine leukemia virus demonstrated that p80 and p120 did not share tryptic peptides. Comparison of the partial proteolytic products generated by treatment of p80 molecules from different tumors with V8 protease did not reveal heterogeneity in p80 among tumors of different strains of mice. Direct labeling and competition blocking experiments with lysates from normal cells failed to provide evidence of p80 synthesis in normal thymus, spleen, or bone marrow. Thus, p80 is a biochemically identified tumor-related antigen of mouse lymphomas.
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34
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Grunwald DJ, Dale B, Dudley J, Lamph W, Sugden B, Ozanne B, Risser R. Loss of viral gene expression and retention of tumorigenicity by Abelson lymphoma cells. J Virol 1982; 43:92-103. [PMID: 6287020 PMCID: PMC256100 DOI: 10.1128/jvi.43.1.92-103.1982] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Lymphomas induced by the Abelson murine leukemia virus (A-MuLV) were examined for the expression of biochemical and biological markers associated with A-MuLV transformation before and after in vivo growth in genetically distinguishable host mice. Although all tumors and clonal lines derived from them initially expressed the A-MuLV-encoded gag fusion protein p160, they ceased synthesis of this molecule after several weeks of growth in vivo as ascites tumors. Transplanted clonal lines continued to express the alloantigenic marker H-2b and the isoenzyme marker Gpi-1b of the donor tumor cells, indicating that the cells were of donor and not host origin. Examination of cellular DNA obtained from p160-positive and derivative p160-negative lines indicated that p160-negative clones had lost A-MuLV-specific proviral sequences as detected by hybridization with several probes. Although the clonal lines no longer expressed p160, they retained their malignant phenotype and continued to express the Abelson antigen, a cell surface marker associated with A-MuLV lymphomagenesis. Continued expression of the A-MuLV genome was not required for maintenance of oncogenic potential under these conditions of in vivo tumor growth.
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Abstract
During the course of immunization of hybrid mice (genotype H-2b/k) with a parental Abelson virus-induced lymphoma (genotype H-2b/b), antibodies were produced to the H-2Kb or H-2Db antigens of the immunizing cells. Such 'anti-self H-2' antibodies demonstrate the existence of autoreactive B-cell clones in hybrid mice, and pose intriguing questions for the nature of self-tolerance.
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Blattner FR, Williams BG, Blechl AE, Denniston-Thompson K, Faber HE, Furlong L, Grunwald DJ, Kiefer DO, Moore DD, Schumm JW, Sheldon EL, Smithies O. Charon phages: safer derivatives of bacteriophage lambda for DNA cloning. Science 1977; 196:161-9. [PMID: 847462 DOI: 10.1126/science.847462] [Citation(s) in RCA: 745] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Charon lambda bacteriophages have been developed as vectors for cloning. Their construction incorporates mutations that make them simple to use and also greatly increases their safety for the biological containment of cloned recombinant DNA. Three of the Charon vector phages, 3A, 4A, and 16A, have been certified for use as EK2 vector-host systems, when propagated in bulk in a special bacterial host, DP50SupF. We present here some of the data on which the safety of these systems was evaluated. DNA fragments ranging in size from 0 to 2.2 X 10(4) base pairs can be cloned in these EK2 Charon phages.
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