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Mutation and expression studies have implicated the Wnt gene family in early developmental decision making in vertebrates and flies. In a detailed comparative analysis, we have used in situ hybridization of 8.0- to 9.5-day mouse embryos to characterize expression of all ten published Wnt genes in the central nervous system (CNS) and limb buds. Seven of the(More)
Formation of the vertebrate limb requires specification of cell position along three axes. Proximal-distal identity is regulated by the apical ectodermal ridge (AER) at the distal tip of the growing limb. Anterior-posterior identity is controlled by signals from the zone of polarizing activity (ZPA) within the posterior limb mesenchyme. Dorsal-ventral(More)
Changes in intermediate filament gene expression occur at key steps in the differentiation of cell types in the mammalian CNS. Neuroepithelial stem cells express the intermediate filament protein nestin and down-regulate it sharply at the transition from proliferating stem cell to postmitotic neuron. Nestin is also expressed in muscle precursors but not in(More)
An important feature of mammalian development is the generation of sexually dimorphic reproductive tracts from the Müllerian and Wolffian ducts. In females, Müllerian ducts develop into the oviduct, uterus, cervix and upper vagina, whereas Wolffian ducts regress. In males, testosterone promotes differentiation of Wolffian ducts into the epididymis, vas(More)
A variety of experimental approaches have underscored the critical role played by secreted polypeptide factors, such as those encoded by members of the Wnt gene family, in many aspects of vertebrate embryogenesis. Recent papers have revealed restricted patterns of Wnt gene expression that delineate important subdivisions within the early forebrain and(More)
The early fate specification of primary mesenchyme cells in sea urchin embryos makes them an attractive system for studying alterations in gene expression and protein synthesis during cell lineage determination and differentiation. To analyze the developmental regulation of gene expression in Strongylocentrotus purpuratus, we have isolated and sequenced(More)
Secreted Wnt proteins regulate many developmental processes in multicellular organisms. We have generated a targeted mutation in the mouse Wnt7b gene. Homozygous Wnt7b mutant mice die at midgestation stages as a result of placental abnormalities. Wnt7b expression in the chorion is required for fusion of the chorion and allantois during placental(More)
The study of spontaneous mutations has aided the understanding of developmental processes. A large collection of spontaneous or "classical" mouse mutations has been accumulated over many decades. One of the mutations causes the postaxial hemimelia (px) phenotype, which consists of limb patterning defects accompanied by Müllerian duct-associated sterility in(More)
The mammalian Wnt gene family consists of at least ten members, all of which share a common structure. The N-terminus encodes a putative signal peptide sequence, suggesting that Wnt proteins are secreted. A number of absolutely conserved cysteine residues imply that inter- or intramolecular disulphide bonding is important to Wnt protein function. Wnt RNAs(More)
In our ever-globalizing world, the amount of interaction between natives of various tongues and multilinguals has grown exponentially. Thus, it logically follows that the amount of code switching, or language alternation, between these multilinguals has likewise increased. This paper explores code switching between individuals involved in multilingual,(More)
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