SEARCH · PubMed Health

Results for “Zebrafish development”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources

PubMed2005

Tenascin-C is involved in motor axon outgrowth in the trunk of developing zebrafish.

Motor axons in the trunk of the developing zebrafish exit from the ventral spinal cord in one ventral root per hemisegment and grow on a common path toward the region of the horizontal myoseptum, where they select their specific pathways. Tenascin-C, a component of the extracellular matrix, is concentrated in this choice region. Adaxial cells and other myotomal cells express tenascin-C mRNA, suggesting that these cells are the source of tenascin-C protein. Overexpressing an axon repellent fragment containing the cysteine-rich region and the epidermal growth factor-like repeats of tenascin-C led to retarded growth of ventral motor nerves between their spinal exit point and the horizontal myoseptum. Injection of a protein fragment containing the same part of tenascin-C also induced slower growth of motor nerves. Conversely, knock down of tenascin-C protein resulted in abnormal lateral branching of ventral motor nerves. In the zebrafish unplugged mutant, in which axons display pathfinding defects in the region of the horizontal myoseptum, tenascin-C immunoreactivity was not detectable in this region, indicating an abnormal extracellular matrix in unplugged. We conclude that tenascin-C is part of a specialized extracellular matrix in the region of the horizontal myoseptum that influences the growth of motor axons.

Amino Acid Sequence↗

PubMed2003

Synaptic plasticity and functionality at the cone terminal of the developing zebrafish retina.

Previous studies have analyzed photoreceptor development, some inner retina cell types, and specific neurotransmitters in the zebrafish retina. However, only minor attention has been paid to the morphology of the synaptic connection between photoreceptors and second order neurons even though it represents the transition from the light sensitive receptor to the neuronal network of the visual system. Here, we describe the appearance and differentiation of pre- and postsynaptic elements at cone synapses in the developing zebrafish retina together with the maturation of the directly connecting second order neurons and a dopaminergic third order feedback-neuron from the inner retina. Zebrafish larvae were examined at developmental stages from 2 to 7dpf (days postfertilization) and in the adult. Synaptic maturation at the photoreceptor terminals was examined with antibodies against synapse associated proteins. The appearance of synaptic plasticity at the so-called spinule-type synapses between cones and horizontal cells was assessed by electron microscopy, and the maturation of photoreceptor downstream connection was identified by immunocytochemistry for GluR4 (AMPA-type glutamate receptor subunit), protein kinase beta(1) (mixed rod-cone bipolar cells), and tyrosine hydroxylase (dopaminergic interplexiform cells). We found that developing zebrafish retinas possess first synaptic structures at the cone terminal as early as 3.5dpf. Morphological maturation of these synapses at 3.5-4dpf, together with the presence of synapse associated proteins at 2.5dpf and the maturation of second order neurons by 5dpf, indicate functional synaptic connectivity and plasticity between the cones and their second order neurons already at 5dpf. However, the mere number of spinules and ribbons at 7dpf still remains below the adult values, indicating that synaptic functionality of the zebrafish retina is not entirely completed at this stage of development.

Animals↗

PubMed2006

The effects of the members of growth hormone family knockdown in zebrafish development.

Growth hormone (GH), prolactin (PRL), and somatolactin (SL) are members of GH/PRL superfamily. These hormones are involved in the regulation of an array of physiological processes, including growth, lactation, and osmoregulation. While recent evidence has shown the GH, PRL, and SL gene transcripts and protein products are expressed during early zebrafish development, their functions at this time of embryogenesis remain unknown. In the current study, antisense morpholino oligonucleotide (MO) inhibition of gh, prl, and sl gene translation was used to examine the effects of gene knockdown on hormone function in zebrafish development. We observed that PRL, SLalpha and SLbeta MO treatment all affected development. PRL MO-treated embryos showed defects in gas bladder inflation, reduced head and eye size, shorter body length and fewer melanophores than untreated controls, whereas SLalpha and SLbeta MO-treated embryos were only defective in gas bladder inflation, GH MO-inhibition of GH specific translation did not lead to any discernable morphological changes within 10 days post fertilization (dpf). The effects of PRL knockdown were further verified using a second PRL morpholino antisense and by a rescue experiment with in vitro transcribed prl mRNA containing 5 nucleotide mismatch within the PRL-MO binding region. These results provide the first evidence that members of the GH/PRL superfamily play a role in proper development of various structures including the head, eyes, melanophores and the gas bladder in zebrafish.

Air Sacs↗

PubMed2000

Structure and function of the developing zebrafish heart.

The combination of optical clarity and large scale of mutants makes the zebrafish vital for developmental biologists. However, there is no comprehensive reference of morphology and function for this animal. Since study of gene expression must be integrated with structure and function, we undertook a longitudinal study to define the cardiac morphology and physiology of the developing zebrafish. Our studies included 48-hr, 5-day, 2-week, 4-week, and 3-month post-fertilization zebrafish. We measured ventricular and body wet weights, and performed morphologic analysis on the heart with H&E and MF-20 antibody sections. Ventricular and dorsal aortic pressures were measured with a servonull system. Ventricular and body weight increased geometrically with development, but at different rates. Ventricle-to-body ratio decreased from 0.11 at 48-hr to 0.02 in adult. The heart is partitioned into sinus venosus, atrium, ventricle, and bulbus arteriosus as identified by the constriction between the segments at 48-hr. Valves were formed at 5-day post-fertilization. Until maturity, the atrium showed extensive pectinate muscles, and the atrial wall increased to two to three cell layers. The ventricular wall and the compact layer increased to three to four cell layers, while the extent and complexity in trabeculation continued. Further thickening of the heart wall was mainly by increase in cell size. The bulbus arteriosus had similar characteristics to the myocardium in early stages, but lost the MF-20 positive staining, and transitioned to smooth muscle layer. All pressures increased geometrically with development, and were linearly related to stage-specific values for body weight (P < 0.05). These data define the parameters of normal cardiac morphology and ventricular function in the developing zebrafish.

Animals↗

PubMed2006

Retinal neuronal cell is a toxicological target of tributyltin in developing zebrafish.

Organotins are among the most common marine pollutants in the world, as they are widely used as antifouling paint on ships and fishing nets. It has been reported that organotin preferentially accumulates in the central nervous system, especially in the retinal neurons of marine organisms including fish. In this study, we investigated the effects of waterborne tributyltin (TBT) on early-stage developing zebrafish (Danio rerio). Below the lethal concentrations, TBT specifically increased the number of apoptotic cells in the retina as well as some cells near trigeminal neurons, detected by terminal transferase-mediated nick-end-labeling staining. Apoptosis peaked at 60 hpf and decreased by 72 hpf, which was associated with macrophage accumulation. Furthermore, the effect of TBT was markedly inhibited by antioxidants, ascorbic acid or trolox. These results suggest that TBT preferentially induces apoptosis in the retinal neuron of developing zebrafish. Oxidative stress may be involved in this toxicological response.

Animals↗

PubMed2005

Epithelial Ca(2+) channel expression and Ca(2+) uptake in developing zebrafish.

The purpose of the present work was to study the possible role of the epithelial Ca(2+) channel (ECaC) in the Ca(2+) uptake mechanism in developing zebrafish (Danio rerio). With rapid amplification of cDNA ends, full-length cDNA encoding the ECaC of zebrafish (zECaC) was cloned and sequenced. The cloned zECaC was 2,578 bp in length and encoded a protein of 709 amino acids that showed up to 73% identity with previously described vertebrate ECaCs. The zECaC was found to be expressed in all tissues examined and began to be expressed in the skin covering the yolk sac of embryos at 24 h postfertilization (hpf). zECaC-expressing cells expanded to cover the skin of the entire yolk sac after embryonic development and began to occur in the gill filaments at 96 hpf, and thereafter zECaC-expressing cells rapidly increased in both gills and yolk sac skin. Corresponding to ECaC expression profile, the Ca(2+) influx and content began to increase at 36-72 hpf. Incubating zebrafish embryos in low-Ca(2+) (0.02 mM) freshwater caused upregulation of the whole body Ca(2+) influx and zECaC expression in both gills and skin. Colocalization of zECaC mRNA and the Na(+)-K(+)-ATPase alpha-subunit (a marker for mitochondria-rich cells) indicated that only a portion of the mitochondria-rich cells expressed zECaC mRNA. These results suggest that the zECaC plays a key role in Ca(2+) absorption in developing zebrafish.

Amino Acid Sequence↗

PubMed2004

Identification and expression pattern of mago nashi during zebrafish development.

In a search for zebrafish genes expressed during early stages of development, we have identified two ESTs encoding proteins related to Drosophila mago nashi. Zebrafish mago nashi codes for a small protein with no clearly identified functional domains, and which is highly conserved during evolution. This paper describes the identification and a detailed gene expression analysis of zebrafish mago nashi during development. Our results demonstrate that mago nashi encodes a maternal transcript detected in both blastomeres and yolk cell at the 1-2 cell stages, and in the blastoderm during segmentation. We show that a putative microtubule-mediated transport of mago nashi mRNA from the vegetal hemisphere into animal blastomeres determines the localization of the transcript in the animal pole, immediately after fertilization. Furthermore, the microtubule array contained into the yolk cell seems to be responsible for the high level of mago nashi transcript detected in the central blastomeres at the 8-16 cell stages. Zygotic mago nashi is expressed into the dorsal-marginal region during gastrulation, and starting from somitogenesis to 24 hpf, the expression domain becomes progressively restricted to the developing neural tube and paraxial structures, and ventrally to the pronephric ducts.

Amino Acid Sequence↗

PubMed2001

Dopamine transporter expression distinguishes dopaminergic neurons from other catecholaminergic neurons in the developing zebrafish embryo.

To characterize the formation of the dopaminergic system in the developing zebrafish CNS, we cloned cDNAs encoding tyrosine hydroxylase (th), an enzyme in dopamine synthesis, and the dopamine transporter (dat), a membrane transport protein which terminates dopamine action by re-uptake. Dopaminergic neurons are first detected between 18 and 19 h post-fertilization in a cluster of cells in the ventral diencephalon. Subsequently, th and dat detection identifies dopaminergic neurons in the olfactory bulb, the pretectum, the retina and the locus coeruleus. Neurons expressing th but not dat are adrenergic or noradrenergic, and are found in the locus coeruleus, the medulla, the likely analog of the carotid body, and precursors of the enteric and sympathetic nervous system.

Amino Acid Sequence↗

PubMed2003

Differential expression of Na,K-ATPase alpha and beta subunit genes in the developing zebrafish inner ear.

We have used whole-mount in situ hybridization to analyze Na,K-ATPase alpha and beta subunit gene expression in the developing zebrafish ear. Four alpha1-like (alpha1a.1, alpha1a.2, alpha1a.4, and alpha1a.5) and two beta (beta1a and beta2b) subunit genes are expressed in ear beginning at mid-somitogenesis. Each gene exhibits a distinct spatial and temporal expression pattern. The alpha1a.1 gene was ubiquitously expressed in the otic epithelium from mid-somitogenesis to 24 hr postfertilization (hpf). Expression of this gene was gradually reduced and by 48 hpf, alpha1a.1 transcripts were no longer detectable in the ear. The alpha1a.2 and alpha1a.5 genes were expressed in regions that correspond to the anterior macula, lateral crista, and semicircular canal projections up to 48 hpf. At later stages, expression of these genes was limited to cells in the dorsolateral septum and semicircular canal projections. alpha1a.4 and beta1a transcripts were ubiquitously expressed during ear development and were present in most otic tissues at 5 days postfertilization (dpf). Expression of the beta2b gene, on the other hand, was restricted to subsets of cells that form sensory epithelia. These results strongly suggest different functional roles for individual Na,K-ATPase genes in zebrafish ear development. Na,K-ATPase genes are likely to represent useful markers for the analysis of zebrafish otogenesis.

Animals↗

PubMed2004

Temporal and spatial expression of gonadotropin releasing hormone (GnRH) in the brain of developing zebrafish (Danio rerio).

Gonadotropin releasing hormone (GnRH) is a neuroendocrine decapeptide found in all vertebrate animals. The best understood function of GnRH is its endocrine function as a releasing hormone acting on the pituitary. But GnRH also functions as a neuromodulator within the nervous system. In a given species, GnRH occurs in a variety of forms that fall into three general categories based on pattern of protein/gene expression in the brain and amino acid sequence. The salmon GnRH (sGnRH), is found in the terminal nerve, where it has a neuromodulatory function. The sGnRH form is also the hypothalamic form in many fishes, although some fishes have a species specific form in the hypothalamus. Finally, chicken-GnRH-II (cGnRH-II), the most highly conserved form, is found in the midbrain where its function remains unclear. Here we have cloned the sGnRH and cGnRH-II cDNAs from zebrafish. By conducting stage specific in situ hybridization in developing zebrafish embryos, we provide a description of the spatial and temporal expression patterns of these genes. The location of sGnRH and cGnRH-II expressing cells is in agreement with previous reports of GnRH in the brains of adult fishes. Our results provide the first developmental description of GnRH gene expression where cGnRH-II and sGnRH are initially expressed at the onset of the first day after fertilization. Unlike what has been reported in many adult fishes, we did not find sGnRH expressed in the hypothalamic population during development.

Animals↗

PubMed2005

The pesticide malathion reduces survival and growth in developing zebrafish.

Malathion is an organophosphorous pesticide widely used to control mosquitoes in urban areas and pests, such as boll weevils, in agricultural areas. Zebrafish, Danio rerio, are model organisms for developmental toxicology research because they are readily available, produce large numbers of clear embryos, and are sensitive to environmental changes. The nonlethal effects of malathion on developing zebrafish embryos, however, previously have not been analyzed quantitatively. We exposed zebrafish embryos to sublethal malathion concentrations to determine malathion's effects on a developing vertebrate. Zebrafish exposed to 0.5, 1.0, or 1.5 mg/L of malathion consistently elicited more rapid hatching from the chorion than zebrafish exposed to 2.0-, 2.5-, or 3.0-mg/L malathion concentrations. In addition, exposure to 2.0, 2.5, or 3.0 mg/L of malathion resulted in significantly shorter body length and eye diameters, indicating that malathion had teratogenic effects on zebrafish embryos. Malathion's action as an acetylcholinesterase inhibitor and the toxicity of the metabolites of malathion may be responsible for malathion's teratogenic effects on fish development.

Animals↗

PubMed2005

Restricted expression of reggie genes and proteins during early zebrafish development.

Reggies are plasma membrane-associated proteins and characteristic markers of lipid-raft microdomains. They are highly conserved from flies to humans and have been implicated in axon regeneration and cell process and contact formation, possibly providing functional platforms for cell-signaling in neurons and other cell types. We analyzed reggie mRNA and protein expression patterns during early zebrafish development. All three zebrafish genes, re-1a, -2a, and -2b, span a considerably diverse set of expression patterns, and their proteins are induced maternally, showing ubiquitous expression at early stages. Although re-2a mRNA can be observed in differentiating neurons in the brain, spinal cord, and neurogenic placodes, re-2b is transcribed mainly in head mesoderm, in neural crest derivates, and along somite boundaries. re-1a mRNA is present at high levels in expression domains that overlap with the combined expression pattern of both re-2 genes except at the somites, where it complements the pattern of re-2b. Immunostaining on embryos reveals reggie protein localization at the cell membrane, at cell-cell contacts, and along all early axon tracts. The early phase of reggie expression suggests a basic and ubiquitous function during the first stages of embryogenesis and into the gastrula period. Upon segmentation, a second phase of expression shows distinctly localized expression patterns, indicating tissue-specific roles and an involvement of re-1a/re-2a in neural development.

Animals↗

PubMed2004

Expression of the winged helix/forkhead gene, foxn4, during zebrafish development.

The winged-helix/forkhead transcription factor gene, foxn4, is expressed in the nervous system of developing and adult zebrafish. Prominent expression sites include the olfactory placode, the basal layer of the olfactory epithelium, the neuroepithelium of the developing retina, the germinal zone of the differentiated eye, regions of motoneuron development in the neural tube and periventricular regions of the brain. The adult thymus is the only major site of foxn4 expression outside of the nervous system.

Amino Acid Sequence↗

PubMed2003

Syndecan-2 is essential for angiogenic sprouting during zebrafish development.

We used a morpholino-based gene-targeting screen to identify a novel protein essential for vascular development using the zebrafish, Danio rerio. We show that syndecan-2, a cell-surface heparan sulfate proteoglycan, is essential for angiogenic sprouting during embryogenesis. The vascular function of syndecan-2 is likely conserved, as zebrafish and mouse syndecan-2 show similar expression patterns around major trunk vessels, and human syndecan-2 can restore angiogenic sprouting in syndecan-2 morphants. In contrast, forced expression of a truncated form of syndecan-2 results in embryos with defects in angiogenesis, indicating that the highly conserved cytoplasmic tail is important for the vascular function of syndecan-2. We further show that vascular endothelial growth factor (VEGF) and syndecan-2 genetically interact in vivo using both gain-of-function and loss-of-function studies in zebrafish. VEGF-mediated ectopic signaling is compromised in syndecan-2 morphants, and ectopic syndecan-2 potentiates ectopic VEGF signaling. Syndecan-2 as a novel angiogenic factor is a potential candidate for use in the development of angiogenesis-based therapies.

5' Untranslated Regions↗

PubMed2006

Gene expression patterns of the ALP family during zebrafish development.

The actinin-associated LIM protein (ALP) genes belong to the PDZ/LIM protein family which is characterized by the presence of both a PDZ and a LIM domain. The ALP subfamily in mammals has four members: ALP, Elfin, Mystique and RIL. In this study, we have annotated and cloned the zebrafish ALP gene family and identified a zebrafish-specific fifth member of the family, the alp-like gene. We compared the zebrafish sequences to their human and mouse orthologues. A phylogenetic analysis based on the amino acid sequences showed the overall high degree of conservation within the family. We describe here the expression patterns for all five ALP family genes during zebrafish development. Whole mount in situ hybridization results revealed common and distinct expression patterns for the five genes. With the exception of elfin, all genes were expressed as maternal RNAs at early developmental stages. Gene expression for all of them appeared regulated and localized in specific regions at the eight different developmental stages studied. Expression for all five genes was observed in the central nervous system (CNS), which led us to further investigate brain-specific expression in sections of embryos at 2 days of development. In summary, we identified the zebrafish orthologues of the ALP family and determined their gene expression patterns during zebrafish embryogenesis. Finally, we compare our results to the limited expression data available for this gene family during mammalian development.

Amino Acid Sequence↗

PubMed2001

Function of Neurolin (DM-GRASP/SC-1) in guidance of motor axons during zebrafish development.

Neurolin (zf DM-GRASP), a transmembrane protein with five extracellular immunoglobulin domains, is expressed by secondary but not primary motoneurons during zebrafish development. The spatiotemporally restricted expression pattern suggests that Neurolin plays a role in motor axon growth and guidance. To test this hypothesis, we injected zebrafish embryos with function-blocking Neurolin antibodies. In injected embryos, secondary motor axons form a broadened bundle along the common path and ectopic branches leave the common path at right angles. Moreover, the formation of the ventral and the rostral projection of secondary motor axons is inhibited during the second day of development. Pathfinding errors, resulting in secondary motor axons growing through ectopic regions of the somites, occur along the common path and in the dorsal and rostral projection. Our data are compatible with the view that Neurolin is involved in the recognition of guidance cues and acts as a receptor on secondary motor axons. Consistent with this idea is the binding pattern of a soluble Neurolin-Fc construct showing that putative ligands are distributed along the common path, the ventral projection, and in the area where the rostral projection develops.

Activated-Leukocyte Cell Adhesion Molecule↗

PubMed2001

Expression of the chaperonin 10 gene during zebrafish development.

We have isolated a cDNA encoding chaperonin 10 (cpn10) from the zebrafish. Using northern, western, and in situ hybridization analysis, we observed that the cpn10 gene is expressed uniformly and ubiquitously throughout embryonic development of the zebrafish. Upregulation of cpn10 expression was observed following exposure of zebrafish embryos to a heat shock of 1 hour at 37 degrees C compared to control embryos raised at 27 degrees C. The extracellular form of Cpn10 called early pregnancy factor (EPF), found in the serum of pregnant mammals, was not detected in the serum of either male or female zebrafish. These expression studies suggest that Cpn10 plays a general role in zebrafish development as well as being consistent with the hypothesis that EPF is involved in the embryo implantation process in mammals.

Animals↗

PubMed2002

Cadherin-17 is required to maintain pronephric duct integrity during zebrafish development.

We have isolated a zebrafish cadherin that is orthologous to human LI-cadherin (CDH17). Zebrafish cdh17 is expressed exclusively in the pronephric ducts during embryogenesis, and in the mesonephros during larval development and adulthood. Like its mammalian ortholog, cdh17 is also expressed in liver and intestine in adult zebrafish. We show that cdh17-positive mesodermal cells do not contribute to the hematopoietic system. Consistent with a cell adhesion role for Cdh17, depletion of Cdh17 function using antisense morpholino oligonucleotides compromised cell cohesion during pronephric duct formation. Our results indicate that Cdh17 is necessary for maintaining the integrity of the pronephric ducts during zebrafish embryogenesis. This finding contrasts with the role of mammalian CDH17, which does not appear to be involved in nephric development.

Amino Acid Sequence↗