Spinal motoneurons of the larval zebrafish

Myers, Paul Z.

doi:10.1002/cne.902360411

Cited by 196 publications

(150 citation statements)

References 14 publications

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“…Spinal motor neurons of zebrafish consist of 3 populations: primary motor neurons, secondary motor neurons, and pectoral fin motor neurons ( Fig. 2E-G, filled arrowheads) (Myers, 1985). In llb embryos, axons of all classes of motor neurons were not observed, while cell bodies reactive with the antibodies that would normally recognize secondary motor neurons (zn-5 antibody for secondary and pectral fin motor neurons) were still located in the ventral part of the spinal cord (Fig.…”

Section: Llb Mutation Causes Defects In the Axonal Outgrowth Of All Cmentioning

confidence: 97%

Islet1 selectively promotes peripheral axon outgrowth in Rohon‐Beard primary sensory neurons

Tanaka

Nojima

Watanabe

et al. 2010

Developmental Dynamics

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We isolated a novel zebrafish mutant, lullaby (llb), and showed that the llb locus encodes the zebrafish orthologue of isl1. Rohon-Beard (RB) primary sensory neurons are multipolar neurons that extend their central axons longitudinally within the spinal cord and also extend their peripheral axons under the skin. In llb embryos, the outgrowth of the peripheral axons of RB neurons was selectively impaired, which correlated with down-regulation of the expression of dihydropyrimidinase-like 3 (dpysl3, also known as collapsin response mediator protein 4, crmp4). Antisense morpholino oligonucleotide (AMO)-mediated knockdown of dpysl3 inhibited the outgrowth of the peripheral axons of RB neurons, and semaphorin 3d (sema3d) AMO enhanced this effect. These data indicate that Dpysl3 is cooperating with Sema3d in the peripheral axon outgrowth, and Isl1 is required for the selective outgrowth of the peripheral axons of RB neurons by maintaining the expression of dpysl3. Developmental Dynamics 240:9-22,

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Section: Llb Mutation Causes Defects In the Axonal Outgrowth Of All Cmentioning

confidence: 97%

Islet1 selectively promotes peripheral axon outgrowth in Rohon‐Beard primary sensory neurons

Tanaka

Nojima

Watanabe

et al. 2010

Developmental Dynamics

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“…Locomotor activity was induced by electrical stimulation of descending axons and monitored by recording from peripheral motor nerves while identified primary (pMN) and secondary (sMN) motoneurons 17 , pre-labeled with Rhodamine dextran, were recorded using the wholecell patch-clamp technique (Fig. 1a).…”

Section: Incremental Recruitment Of Motoneuron Poolsmentioning

confidence: 99%

“…The recruitment of interneurons at faster speeds is accompanied by the silencing of those driving movements at slower speeds [13][14][15] . In zebrafish, motoneurons develop along the dorso-ventral axis with the early born, large primary motoneurons located dorsally and later born, small secondary motoneurons located ventrally [16][17][18][19] . At early developmental stages, zebrafish larvae swim in bursts and only embryonic muscle fibers are developed [20][21][22] .…”

Section: Introductionmentioning

confidence: 99%

Principles governing recruitment of motoneurons during swimming in zebrafish

et al. 2010

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Locomotor movements are coordinated by a network of neurons that produces sequential muscle activation. Different motoneurons need to be recruited in an orderly manner to generate movement with appropriate speed and force. However, the mechanisms governing the recruitment order have not been fully clarified. Here we show, using an in vitro juvenile/adult zebrafish brainstem-spinal cord preparation, that motoneurons are organized in four pools with specific topographic locations and are incrementally recruited to produce swimming at different frequencies. The threshold of recruitment is not dictated by the input resistance of motoneurons but is rather set by a combination of specific biophysical properties and the strength of the synaptic currents. Thus, our results provide insights into the cellular and synaptic computations governing recruitment of motoneurons during locomotion.3

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“…Interestingly, development of secondary motor neurons, which more closely resemble mammalian motor neurons (60), was severely impaired in the COX-deficient zebrafish. Secondary motor neuron axons extend later than primary motor neurons (61) and some innervate more than one hemisegment (58,62). In most cases the majority of secondary motor neuron axons in the rostral two-thirds of the COX-deficient fish were absent (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Axonal outgrowth of secondary motor neurons, which are most similar to mammalian and avian motor neurons (60), occurs later than primary motor neurons (61). They are also more numerous, and some innervate more than one hemisegment (58,62). To assess the effects of COX deficiency on secondary motor neuron development, cox5aa-MO, cox5ab-MO, and surf1-MO were injected into embryos of Tg(gata2:GFP), a transgenic line of zebrafish that express GFP in a subset of secondary motor neurons and occasionally in descending interneurons and Rohon-Beard cells (63).…”

Section: Reduction Of Either Coxva or Surf1mentioning

confidence: 99%

Early Developmental Pathology Due to Cytochrome c Oxidase Deficiency Is Revealed by a New Zebrafish Model

Baden

Murray²,

Capaldi

et al. 2007

Journal of Biological Chemistry

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Deficiency of cytochrome c oxidase (COX) is associated with significant pathology in humans. However, the consequences for organogenesis and early development are not well understood. We have investigated these issues using a zebrafish model. COX deficiency was induced using morpholinos to reduce expression of CoxVa, a structural subunit, and Surf1, an assembly factor, both of which impaired COX assembly. Reduction of COX activity to 50% resulted in developmental defects in endodermal tissue, cardiac function, and swimming behavior. Cellular investigations revealed different underlying mechanisms. Apoptosis was dramatically increased in the hindbrain and neural tube, and secondary motor neurons were absent or abnormal, explaining the motility defect. In contrast, the heart lacked apoptotic cells but showed increasingly poor performance over time, consistent with energy deficiency. The zebrafish model has revealed tissue-specific responses to COX deficiency and holds promise for discovery of new therapies to treat mitochondrial diseases in humans.Cytochrome c oxidase (COX) 2 is the terminal enzyme in the mitochondrial respiratory chain. Embedded in the inner mitochondrial membrane, COX couples the vectoral movement of protons across the inner membrane to the transfer of electrons from reduced cytochrome c to molecular oxygen. Mammalian COX consists of 13 subunits, 10 of which (COXIV-COXVIII) are encoded by nuclear DNA. The other three subunits (COXI, COXII, and COXIII) are encoded by the mitochondrial DNA (mtDNA) and constitute the hydrophobic/catalytic core of the enzyme. Assembly of COX is a complicated process involving multiple assembly factors and chaperones, including COX10 -11, COX15-20, COX23, SCO1, SCO2, and SURF1 (1). Deficiency in COX activity is associated with significant pathology usually affecting highly metabolic tissues, including brain, muscle, and eyes (2, 3). For example, COX deficiency is commonly associated with Leigh syndrome, an early-onset disorder resulting in progressive central nervous system degeneration and early lethality (4, 5). The majority of cases of COX-deficient Leigh syndrome are a result of mutations in SURF1, which encodes a COX assembly factor (6, 7). Mutations in SURF1 impair the incorporation of subunit II, resulting in a buildup of an early COX assembly intermediate, decrease in other COX subunits, and a decrease in COX activity (8 -11). COX deficiency may also be complicated by cardiac pathology, including hypertrophic and dilated cardiomyopathies (12, 13), and conduction defects (14).COX deficiency is detrimental during the prenatal period as well. The incidence of this disorder has prompted the application of COX activity assays to prenatal samples obtained by chorionic villus biopsy and amniocentesis in specific cases (15,16). Prenatal diagnostics of this type have preparatory value for parents and physicians and may also be used to explain previous pregnancy losses (17). However, our incomplete understanding of the metabolic requirements of different tissues and ...

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Spinal motoneurons of the larval zebrafish

Cited by 196 publications

References 14 publications

Islet1 selectively promotes peripheral axon outgrowth in Rohon‐Beard primary sensory neurons

Islet1 selectively promotes peripheral axon outgrowth in Rohon‐Beard primary sensory neurons

Principles governing recruitment of motoneurons during swimming in zebrafish

Early Developmental Pathology Due to Cytochrome c Oxidase Deficiency Is Revealed by a New Zebrafish Model

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