Knockdown of zebrafish Nav1.6 sodium channel impairs embryonic locomotor activities

Chen, Yau Hung; Huang, Fong Lee; Yi, Cheng; Wu, Chia Jung; Yang, Cheng; Tsay, Huey Jen

doi:10.1007/s11373-007-9200-4

Cited by 12 publications

(17 citation statements)

References 27 publications

(39 reference statements)

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“…As mentioned above, mutation of single genes can also lead to severe muscle phenotypes, so it is possible that splicing mis-regulation of only a few key targets could lead to paralysis and heart dysfunction. Proteins identified so far that are regulated by the Rbfox network include Syne1a, a Nesprin-related protein sometimes involved in pathogenesis of Emery–Dreifuss muscular dystrophy in humans (Zhang et al, 2007); Svil, a plasma membrane protein for which a muscle-specific isoform has been shown to interact with F-actin in skeletal muscle (Oh et al, 2003; Pope et al, 1998); the membrane transporters Gabrg2 and Scn8aa (Baulac et al, 2001; Chen et al, 2008); and the RNA binding protein Fxr1, which regulates somite formation in frogs (Huot et al, 2005). Interestingly, recent work showed that the completely immotile zebrafish relaxed / cacnb1 null mutant (Granato et al, 1996) is fully rescued by injection of the muscle-specific cacnb1 isoform and not other closely related isoforms (Schredelseker et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions

Gallagher

Arribere

Geurts

et al. 2011

Developmental Biology

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Rbfox RNA binding proteins are implicated as regulators of phylogenetically-conserved alternative splicing events important for muscle function. To investigate the function of rbfox genes, we used morpholino-mediated knockdown of muscle-expressed rbfox1l and rbfox2 in zebrafish embryos. Single and double morphant embryos exhibited changes in splicing of overlapping sets of bioinformatically-predicted rbfox target exons, many of which exhibit a muscle-enriched splicing pattern that is conserved in vertebrates. Thus, conservation of intronic Rbfox binding motifs is a good predictor of Rbfox-regulated alternative splicing. Morphology and development of single morphant embryos was strikingly normal; however, muscle development in double morphants was severely disrupted. Defects in cardiac muscle were marked by reduced heart rate and in skeletal muscle by complete paralysis. The predominance of wavy myofibers and abnormal thick and thin filaments in skeletal muscle revealed that myofibril assembly is defective and disorganized in double morphants. Ultra-structural analysis revealed that although sarcomeres with electron dense M- and Z-bands are present in muscle fibers of rbfox1l/rbox2 morphants, they are substantially reduced in number and alignment. Importantly, splicing changes and morphological defects were rescued by expression of morpholino-resistant rbfox cDNA. Additionally, a target-blocking MO complementary to a single UGCAUG motif adjacent to an rbfox target exon of fxr1 inhibited inclusion in a similar manner to rbfox knockdown, providing evidence that Rbfox regulates the splicing of target exons via direct binding to intronic regulatory motifs. We conclude that Rbfox proteins regulate an alternative splicing program essential for vertebrate heart and skeletal muscle function.

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Section: Discussionmentioning

confidence: 99%

Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions

Gallagher

Arribere

Geurts

et al. 2011

Developmental Biology

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“…The common trace metal Cu potently disrupts olfaction in salmonids (Baldwin et al , 2003; Sandahl et al , 2004; McIntyre et al , 2008), and we have shown in a microarray study using zebrafish that Cu-olfactory impairment may be largely attributed to a transcriptional repression of conserved signal transduction genes in the zebrafish olfactory system (Tilton et al , 2008). The pesticide chlorpyrifos (CPF) is an organophosphate pesticide that alters neuronal development, synaptic stability and growth in rat and human neuronal cells (Garcia et al , 2002; Howard et al , 2005; Chen et al , 2008; Roegge et al , 2008) and is highly toxic to the fish olfactory system (Sandahl et al , 2004; Tierney et al , 2007a). In the current study, we investigated gene expression patterns underlying olfactory injury caused by exposure to CPF alone, or as a binary mixture in combination with Cu.…”

Section: Introductionmentioning

confidence: 99%

Transcriptional impact of organophosphate and metal mixtures on olfaction: Copper dominates the chlorpyrifos-induced response in adult zebrafish

Tilton

Bammler

et al. 2011

Aquatic Toxicology

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Chemical exposures in fish have been linked to loss of olfaction leading to an inability to detect predators and prey and decreased survival. However, the mechanisms underlying olfactory neurotoxicity are not well characterized, especially in environmental exposures which involve chemical mixtures. We used zebrafish to characterize olfactory transcriptional responses by two model olfactory inhibitors, the pesticide chlorpyrifos (CPF) and mixtures of CPF with the neurotoxic metal copper (Cu). Microarray analysis was performed on RNA from olfactory tissues of zebrafish exposed to CPF alone or to a mixture of CPF and Cu. Gene expression profiles were analyzed using Principal Component Analysis and hierarchical clustering, whereas gene set analysis was used to identify biological themes in the microarray data. Microarray results were confirmed by real-time PCR on genes serving as potential biomarkers of olfactory injury. In addition, we mined our previously published Cu-induced zebrafish olfactory transcriptional response database (Tilton et al., 2008) for the purposes of discriminating pathways of olfaction impacted by either the individual agents or the CPF-Cu mixture transcriptional signatures. CPF exposure altered the expression of gene pathways associated with cellular morphogenesis and odorant binding, but not olfactory signal transduction, a known olfactory pathway for Cu. The mixture profiles shared genes from the Cu and CPF datasets, whereas some genes were altered only by the mixtures. The transcriptional signature of the mixtures was more similar to that in zebrafish exposed to Cu alone then for CPF. In conclusion, exposure to a mixture containing a common environmental metal and pesticide causes a unique transcriptional signature that is heavily influenced by the metal, even when organophosphate predominates. Our findings support using zebrafish microarray analysis to elucidate mechanisms of olfactory loss and to identify the components of mixtures which most strongly contribute to olfactory injury.

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“…One possibility is that such muscle malformation in D-serine-injected zebrafish embryos might result from D-serine affecting the NMDA receptors of the pre-synapse and disturbing the release of neurotransmitters from the axon terminals. Previous studies have shown that knockdown of neuronal activity led to impairment of muscle development 28 , 38 . In this regard, D-serine-induced muscle defects might be the consequences of excitotoxicity of NMDA receptors.…”

Section: Discussionmentioning

confidence: 99%

“…The spontaneous in-chorion contraction of zebrafish embryos was analyzed as previously described 28 , 29 . Briefly, zebrafish embryos at 24 hpf without or with injection of different concentrations (100, 500 and 1000 ppm) of D-serine were collected and recorded.…”

Section: Methodsmentioning

confidence: 99%

Overdose of D-serine Induces Movement Disorder and Neuromuscular Changes of Zebrafish Larvae

et al. 2014

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D-serine is a well-known activator of N-methyl-D-aspartate receptors; however, little is known about the teratogenic effects of D-serine overdose during early embryonic development. Here, we used zebrafish as a model to test toxicity and teratogenicity, since they have transparent eggs, making the organogenesis of zebrafish embryos easier to be observed. After D-serine injection (100–1000 ppm), the most evident defective phenotypes were bent trunk phenotypes, including malformed somite boundary, twisted body axis and shorter body length. As the injection dosages increased, the rates of embryos with bent trunk phenotypes decreased (0% for 0 ppm, n=573; 59.9~84.3% for 100–1000 ppm of D-serine, n=383–451). In addition, D-serine-injected embryos exhibited significantly reduced the frequencies of spontaneous in-chorion contraction (21.7 for 0 ppm vs. 18.3–0.9 for 100–1000 ppm D-serine, n=30) in comparison with mock-treated controls (0 ppm). Subtle changes are easily observed by staining with specific monoclonal antibodies F59, Znp1, Zn5 and α-bungarotoxin to detect morphological changes in muscle fibers, primary motor axons, secondary motor axon projections and neuromuscular junctions, respectively. Our data show that overdose of D-serine leads to misalignment of muscle fibers and motor neuron defects, especially secondary motor neuron axonal growth defects.

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Knockdown of zebrafish Nav1.6 sodium channel impairs embryonic locomotor activities

Cited by 12 publications

References 27 publications

Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions

Rbfox-regulated alternative splicing is critical for zebrafish cardiac and skeletal muscle functions

Transcriptional impact of organophosphate and metal mixtures on olfaction: Copper dominates the chlorpyrifos-induced response in adult zebrafish

Overdose of D-serine Induces Movement Disorder and Neuromuscular Changes of Zebrafish Larvae

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