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HOX genes specify cell fate in the anterior-posterior axis of animal embryos. Invertebrate chordates have one HOX cluster, but mammals have four, suggesting that cluster duplication facilitated the evolution of vertebrate body plans. This report shows that zebrafish have seven hox clusters. Phylogenetic analysis and genetic mapping suggest a chromosome(More)
Dorsal mesoderm is thought to provide important signals for axis formation and neural differentiation in vertebrate embryos. We have examined induction and patterning in a zebrafish mutant, no tail, that lacks a derivative of dorsal mesoderm, the notochord. Despite the absence of a differentiated notochord, development of the central nervous system(More)
The floor plate is a set of epithelial cells present in the ventral midline of the neural tube in vertebrates that seems to have an important role in the developmental patterning of central nervous system fibre pathways, and arrangements of specific neurons. The floor plate arises from dorsal ectodermal cells closely associated with the mesoderm that forms(More)
The animal/vegetal axis of the zebrafish egg is established during oogenesis, but the molecular factors responsible for its specification are unknown. As a first step towards the identification of such factors, we present here the first demonstration of asymmetrically distributed maternal mRNAs in the zebrafish oocyte. To date, we have distinguished three(More)
BACKGROUND In amphibians, the Nieuwkoop center--a primary inducing region--has a central role in the induction of dorsal mesodermal cells to form the Spemann organizer. In teleosts, such as the zebrafish, Danio rerio, the functional equivalent of the amphibian Spemann organizer is the dorsal shield. Historically, a small region of the teleost yolk syncytial(More)
Transcription factors of the STAT family are required for cellular responses to multiple signaling molecules. After ligand binding-induced activation of cognate receptors, STAT proteins are phosphorylated, hetero- or homodimerize, and translocate to the nucleus. Subsequent STAT binding to specific DNA elements in the promoters of signal-responsive genes(More)
During embryonic development, muscles differentiate in the appropriate places and motoneurone growth cones find the appropriate muscles; both events occur concurrently and with remarkable specificity. What are the cellular interactions that orchestrate this coordinated development of nerve and muscle? In the development of vertebrate skeletal muscles,(More)