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Systematic genome-wide mutagenesis screens for embryonic phenotypes have been instrumental in the understanding of invertebrate and plant development. Here, we report the results from the first application of such a large-scale genetic screening to vertebrate development. Male zebrafish were mutagenized with N-ethyl N-nitrosourea to induce mutations in(More)
In a large scale mutagenesis screen for embryonic mutants in zebrafish, we have identified 63 mutations in 24 loci affecting the morphogenesis of the zebrafish brain. The expression of marker genes and the integrity of the axonal scaffold have been studied to investigate abnormalities in regionalization, neurogenesis and axonogenesis in the brain. Mutants(More)
One of the major challenges of developmental biology is understanding the inductive and morphogenetic processes that shape the vertebrate embryo. In a large-scale genetic screen for zygotic effect, embryonic lethal mutations in zebrafish we have identified 25 mutations that affect specification of cell fates and/or cellular rearrangements during(More)
A layered organization of cells is a common architectural feature of many neuronal formations. Mutations of the zebrafish gene nagie oko (nok) produce a severe disruption of retinal architecture, indicating a key role for this locus in neuronal patterning. We show that nok encodes a membrane-associated guanylate kinase-family scaffolding protein. Nok(More)
Cilia play diverse roles in vertebrate and invertebrate sensory neurons. We show that a mutation of the zebrafish oval (ovl) locus affects a component of the ciliary transport (IFT) mechanism, the IFT88 polypeptide. In mutant retina, cilia are generated but not maintained, producing the absence of photoreceptor outer segments. A loss of cilia also occurs in(More)
The seven major cell classes of the vertebrate retina are organized with remarkable precision into distinct layers. The appearance of this architecture during embryogenesis raises two questions of general importance. How do individual cell classes acquire their specialized structures and functions if they all originate from a morphologically uniform cell(More)
BACKGROUND Polarity is an essential attribute of most eukaryotic cells. One of the most prominent features of cell polarity in many tissues is the subdivision of cell membrane into apical and basolateral compartments by a belt of cell junctions. The proper formation of this subdivision is of key importance. In sensory cells, for example, the apical membrane(More)
Embryos from mutagenized zebrafish were screened for disruptions in retinal lamination to identify factors involved in vertebrate retinal cell specification and differentiation. Two alleles of a recessive mutation, young, were isolated in which final differentiation and normal lamination of retinal cells were blocked. Early aspects of retinogenesis(More)
Although the zebrafish has become an important model for genetic analysis of the vertebrate auditory system, a comprehensive description of the zebrafish ear has been provided for embryonic and larval development only (Haddon and Lewis [1996] J. Comp. Neurol. 365:113). Here we describe the development of sensory maculae in juvenile fish and the morphology(More)
In a large scale screen for genetic defects in zebrafish embryogenesis we identified 49 mutations affecting development of the retina. Based on analysis of living embryos as well as histological sections, we grouped the isolated mutations into six phenotypic categories. (1) Mutations in three loci result in a loss of wild-type laminar pattern of the neural(More)