About the Authors: Didier Y. R. Stainier * E-mail: didier.stainier@mpi-bn.mpg.de (DYRS); cmoens@fredhutch.org (CBM) Affiliation: Department of Developmental Genetics, Max Planck Institute for Heart ...and Lung Research, Bad Nauheim, Germany ORCID http://orcid.org/0000-0002-0382-0026 Erez Raz Affiliation: Institute of Cell Biology, ZBME, University of Münster, Münster, Germany ORCID http://orcid.org/0000-0002-6347-3302 Nathan D. Lawson Affiliation: Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America Stephen C. Ekker Affiliation: Mayo Clinic, Rochester, Minnesota, United States of America Rebecca D. Burdine Affiliation: Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America Judith S. Eisen Affiliation: Institute of Neuroscience, University of Oregon, Eugene, Oregon, United States of America ORCID http://orcid.org/0000-0003-1229-1696 Philip W. Ingham Affiliations Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, The Living Systems Institute, University of Exeter, Exeter, United Kingdom Stefan Schulte-Merker Affiliation: Institute of Cardiovascular Organogenesis and Regeneration, WWU Münster, Faculty of Medicine, Münster, Germany Deborah Yelon Affiliation: Division of Biological Sciences, University of California, San Diego, La Jolla, California, United States of America Brant M. Weinstein Affiliation: Division of Developmental Biology, NICHD, NIH, Bethesda, Maryland, United States of America Mary C. Mullins Affiliation: Department of Cell and Developmental Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America ORCID http://orcid.org/0000-0002-9979-1564 Stephen W. Wilson Affiliation: Department of Cell and Developmental Biology, University College London, London, United Kingdom ORCID http://orcid.org/0000-0002-8557-5940 Lalita Ramakrishnan Affiliation: Molecular Immunity Unit, Department of Medicine, University of Cambridge, MRC Laboratory of Molecular Biology, Cambridge, United Kingdom Sharon L. Amacher Affiliation: Departments of Molecular Genetics and Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio, United States of America Stephan C. F. Neuhauss Affiliation: Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland ORCID http://orcid.org/0000-0002-9615-480X Anming Meng Affiliation: School of Life Sciences, Tsinghua University, Beijing, China Naoki Mochizuki Affiliation: National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan ORCID http://orcid.org/0000-0002-3938-9602 Pertti Panula Affiliation: Department of Anatomy and Neuroscience Center, University of Helsinki, Helsinki, Finland Cecilia B. Moens * E-mail: didier.stainier@mpi-bn.mpg.de (DYRS); cmoens@fredhutch.org (CBM) Affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of AmericaCitation: Stainier DYR, Raz E, Lawson ND, Ekker SC, Burdine RD, Eisen JS, et al. Additionally, mutant alleles for many genes are now readily available through zebrafish community resource centers. ...MOs should be used alongside mutant(s) for the corresponding gene. ...a word of caution that previous publication of MOs is not a guarantee of their fidelity, particularly if a new phenotype is being described. ...we hope that these brief and mostly conceptual guidelines will assist scientists working with zebrafish as well as those assessing manuscripts and grant proposals based on experiments using zebrafish.
Adult zebrafish are robustly social animals whereas larva is not. We designed an assay to determine at what stage of development zebrafish begin to interact with and prefer other fish. One week old ...zebrafish do not show significant social preference whereas most 3 weeks old zebrafish strongly prefer to remain in a compartment where they can view conspecifics. However, for some individuals, the presence of conspecifics drives avoidance instead of attraction. Social preference is dependent on vision and requires viewing fish of a similar age/size. In addition, over the same 1-3 weeks period larval zebrafish increasingly tend to coordinate their movements, a simple form of social interaction. Finally, social preference and coupled interactions are differentially modified by an NMDAR antagonist and acute exposure to ethanol, both of which are known to alter social behavior in adult zebrafish.
Left-right asymmetries are most likely a universal feature of bilaterian nervous systems and may serve to increase neural capacity by specializing equivalent structures on left and right sides for ...distinct roles 1. However, little is known about how asymmetries are encoded within vertebrate neural circuits and how lateralization influences processing of information in the brain. Consequently, it remains unclear the extent to which lateralization of the nervous system is important for normal cognitive and other brain functions and whether defects in lateralization contribute to neurological deficits 2. Here we show that sensory responses to light and odor are lateralized in larval zebrafish habenulae and that loss of brain asymmetry leads to concomitant loss of responsiveness to either visual or olfactory stimuli. We find that in wild-type zebrafish, most habenular neurons responding to light are present on the left, whereas neurons responding to odor are more frequent on the right. Manipulations that reverse the direction of brain asymmetry reverse the functional properties of habenular neurons, whereas manipulations that generate either double-left- or double-right-sided brains lead to loss of habenular responsiveness to either odor or light, respectively. Our results indicate that loss of brain lateralization has significant consequences upon sensory processing and circuit function.
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•Habenular neuron responses to light and odor stimuli are lateralized•Lateralized habenular light responses depend upon the eyes•Loss of brain asymmetry leads to a loss of either light or odor responses
Dreosti et al. show that sensory responses to light and odor are lateralized in the larval zebrafish habenula and that loss of brain asymmetry leads to a loss of responses to visual or olfactory stimuli, suggesting that brain lateralization may play a significant role in sensory processing and circuit function.
Using high-resolution live imaging in zebrafish, we show that presumptive eye cells acquire apicobasal polarity and adopt neuroepithelial character prior to other regions of the neural plate. ...Neuroepithelial organization is first apparent at the margin of the eye field, whereas cells at its core have mesenchymal morphology. These core cells subsequently intercalate between the marginal cells contributing to the bilateral expansion of the optic vesicles. During later evagination, optic vesicle cells shorten, drawing their apical surfaces laterally relative to the basal lamina, resulting in further laterally directed evagination. The early neuroepithelial organization of the eye field requires Laminin1, and ectopic Laminin1 can redirect the apicobasal orientation of eye field cells. Furthermore, disrupting cell polarity through combined abrogation of the polarity protein Pard6γb and Laminin1 severely compromises optic vesicle evagination. Our studies elucidate the cellular events underlying early eye morphogenesis and provide a framework for understanding epithelialization and complex tissue formation.
•Live imaging reveals cellular behaviors during optic vesicle evagination•Eye field cells acquire apicobasal polarization prior to other neural cells•Laminin1 is required for the epithelial organization of basal eye field cells•Mesenchymal-like core eye field cells intercalate into the basal epithelium
By performing high-resolution live-imaging experiments in zebrafish, Ivanovitch et al. resolve the dynamic cell behaviors underlying optic vesicle formation. The first event in this process is Laminin1-dependent epithelialization of cells at the margin of the eye field. Subsequent epithelial remodeling and cell intercalation events shape the evaginating optic vesicles.
High-altitude hypoxia (reduced inspired oxygen tension due to decreased barometric pressure) exerts severe physiological stress on the human body. Two high-altitude regions where humans have lived ...for millennia are the Andean Altiplano and the Tibetan Plateau. Populations living in these regions exhibit unique circulatory, respiratory, and hematological adaptations to life at high altitude. Although these responses have been well characterized physiologically, their underlying genetic basis remains unknown. We performed a genome scan to identify genes showing evidence of adaptation to hypoxia. We looked across each chromosome to identify genomic regions with previously unknown function with respect to altitude phenotypes. In addition, groups of genes functioning in oxygen metabolism and sensing were examined to test the hypothesis that particular pathways have been involved in genetic adaptation to altitude. Applying four population genetic statistics commonly used for detecting signatures of natural selection, we identified selection-nominated candidate genes and gene regions in these two populations (Andeans and Tibetans) separately. The Tibetan and Andean patterns of genetic adaptation are largely distinct from one another, with both populations showing evidence of positive natural selection in different genes or gene regions. Interestingly, one gene previously known to be important in cellular oxygen sensing, EGLN1 (also known as PHD2), shows evidence of positive selection in both Tibetans and Andeans. However, the pattern of variation for this gene differs between the two populations. Our results indicate that several key HIF-regulatory and targeted genes are responsible for adaptation to high altitude in Andeans and Tibetans, and several different chromosomal regions are implicated in the putative response to selection. These data suggest a genetic role in high-altitude adaption and provide a basis for future genotype/phenotype association studies necessary to confirm the role of selection-nominated candidate genes and gene regions in adaptation to altitude.
The dorsal diencephalon, or epithalamus, contains the bilaterally paired habenular nuclei and the pineal complex. The habenulae form part of the dorsal diencephalic conduction (DDC) system, a highly ...conserved pathway found in all vertebrates. In this review, we shall describe the neuroanatomy of the DDC, consider its physiology and behavioural involvement, and discuss examples of neural asymmetries within both habenular circuitry and the pineal complex. We will discuss studies in zebrafish, which have examined the organization and development of this circuit, uncovered how asymmetry is represented at the level of individual neurons and determined how such left-right differences arise during development.
Summary Background Surgery is a foundational component of health-care systems. However, previous efforts to integrate surgical services into global health initiatives do not reflect the scope of ...surgical need and many health systems do not provide essential interventions. We estimate the minimum global volume of surgical need to address prevalent diseases in 21 epidemiological regions from the Global Burden of Disease Study 2010 (GBD). Methods Prevalence data were obtained from GBD 2010 and organised into 119 disease states according to the WHO's Global Health Estimate (GHE). These data, representing 187 countries, were then apportioned into the 21 GBD epidemiological regions. Using previously defined values for the incident need for surgery for each of the 119 GHE disease states, we calculate minimum global need for surgery based on the prevalence of each condition in each region. Findings We estimate that at least 321·5 million surgical procedures would be needed to address the burden of disease for a global population of 6·9 billion in 2010. Minimum rates of surgical need vary across regions, ranging from 3383 operations per 100 000 in central Latin America to 6495 operations per 100 000 in western sub-Saharan Africa. Global surgical need also varied across subcategories of disease, ranging from 131 412 procedures for nutritional deficiencies to 45·8 million procedures for unintentional injuries. Interpretation The estimated need for surgical procedures worldwide is large and addresses a broad spectrum of disease states. Surgical need varies between regions of the world according to disease prevalence and many countries do not meet the basic needs of their populations. These estimates could be useful for policy makers, funders, and ministries of health as they consider how to incorporate surgical capacity into health systems. Funding US National Institutes of Health.
Blood vessel networks expand in a 2-step process that begins with vessel sprouting and is followed by vessel anastomosis. Vessel sprouting is induced by chemotactic gradients of the vascular ...endothelial growth factor (VEGF), which stimulates tip cell protrusion. Yet it is not known which factors promote the fusion of neighboring tip cells to add new circuits to the existing vessel network. By combining the analysis of mouse mutants defective in macrophage development or VEGF signaling with live imaging in zebrafish, we now show that macrophages promote tip cell fusion downstream of VEGF-mediated tip cell induction. Macrophages therefore play a hitherto unidentified and unexpected role as vascular fusion cells. Moreover, we show that there are striking molecular similarities between the pro-angiogenic tissue macrophages essential for vascular development and those that promote the angiogenic switch in cancer, including the expression of the cell-surface proteins TIE2 and NRP1. Our findings suggest that tissue macrophages are a target for antiangiogenic therapies, but that they could equally well be exploited to stimulate tissue vascularization in ischemic disease.
How action potentials regulate myelination by oligodendrocytes is uncertain. We show that neuronal activity raises Ca
in developing oligodendrocytes in vivo and that myelin sheath elongation is ...promoted by a high frequency of Ca
transients and prevented by Ca
buffering. Sheath elongation occurs ~1 h after Ca
elevation. Sheath shortening is associated with a low frequency of Ca
transients but with longer duration Ca
bursts. Thus, Ca
controls myelin sheath development.
Hundreds of human genes are associated with neurological diseases, but translation into tractable biological mechanisms is lagging. Larval zebrafish are an attractive model to investigate genetic ...contributions to neurological diseases. However, current CRISPR-Cas9 methods are difficult to apply to large genetic screens studying behavioural phenotypes. To facilitate rapid genetic screening, we developed a simple sequencing-free tool to validate gRNAs and a highly effective CRISPR-Cas9 method capable of converting >90% of injected embryos directly into F0 biallelic knockouts. We demonstrate that F0 knockouts reliably recapitulate complex mutant phenotypes, such as altered molecular rhythms of the circadian clock, escape responses to irritants, and multi-parameter day-night locomotor behaviours. The technique is sufficiently robust to knockout multiple genes in the same animal, for example to create the transparent triple knockout
fish for imaging. Our F0 knockout method cuts the experimental time from gene to behavioural phenotype in zebrafish from months to one week.
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