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Zebrafish embryos and larvae have stage-specific patterns of motility or locomotion. Two embryonic structures accomplish this behavior: the central nervous system (CNS) and skeletal muscles. To identify genes that are functionally involved in mediating and controlling different patterns of embryonic and larval motility, we included a simple touch response(More)
Somitogenesis is the basis of segmentation of the mesoderm in the trunk and tail of vertebrate embryos. Two groups of mutants with defects in this patterning process have been isolated in our screen for zygotic mutations affecting the embryonic development of the zebrafish (Danio rerio). In mutants of the first group, boundaries between individual somites(More)
A significant proportion of neurons in the brain undergo programmed cell death. In order to prevent the diffusion of damaging degradation products, dying neurons are quickly digested by microglia. Despite the importance of microglia in several neuronal pathologies, the mechanism underlying their degradation of neurons remains elusive. Here, we exploit a(More)
Zebrafish have become a popular organism for the study of vertebrate gene function. The virtually transparent embryos of this species, and the ability to accelerate genetic studies by gene knockdown or overexpression, have led to the widespread use of zebrafish in the detailed investigation of vertebrate gene function and increasingly, the study of human(More)
We have analyzed the contributions made by maternal and zygotic genes to the establishment of the expression patterns of four zygotic patterning genes: decapentaplegic (dpp), zerknüllt (zen), twist (twi), and snail (sna). All of these genes are initially expressed either dorsally or ventrally in the segmented region of the embryo, and at the poles. In the(More)
The dorsoventral axis of the Drosophila embryo is determined by a morphogen gradient established by the action of 12 maternal-effect genes: the dorsal group genes and cactus. One of the dorsal group genes, dorsal (dl), encodes the putative morphogen. Although no overall asymmetry in the distribution of dorsal protein is observed, a gradient of nuclear(More)
goosecoid is an immediate early gene expressed at the dorsal blastoporal lip of the Xenopus gastrula. Microinjection experiments have suggested a direct role for goosecoid in organizing the dorsoventral axis of the frog embryo. Here we characterize the zebrafish homologue of goosecoid (gsc) and compare its expression to that of Brachyury or no tail (ntl),(More)
The mouse T (Brachyury) gene is required for normal mesoderm development and the extension of the body axis. Recently, two mutant alleles of a zebrafish gene, no tail (ntl), have been isolated (Halpern, M. E., Ho., R. K., Walker, C. and Kimmel, C. B. (1993) Cell 75, 99-111). ntl mutant embryos resemble mouse T/T mutant embryos in that they lack a(More)
The bicoid (bcd) protein in a Drosophila embryo is derived from an anteriorly localized mRNA and comes to be distributed in an exponential concentration gradient along the anteroposterior axis. To determine whether the levels of bcd protein are directly related to certain cell fates, we manipulated the density and distribution of bcd mRNA by genetic means,(More)