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The dorsal blastopore lip of the early Xenopus laevis gastrula can organize a complete secondary body axis when transplanted to another embryo. A search for potential gene regulatory components specifically expressed in the organizer was undertaken that resulted in the identification of four types of complementary DNAs from homeobox-containing genes that(More)
XIHbox 6 is an early spatially restricted marker for molecular studies of neural induction. The sequence of the full-length XIHbox 6 protein is reported. An antibody raised against a beta-galactosidase/XIHbox 6 fusion protein was used to analyze the expression of XIHbox 6 proteins during frog embryogenesis. The anterior border of XIHbox 6 expression lies(More)
The dorsal ectoderm of the vertebrate gastrula was proposed by Nieuwkoop to be specified towards an anterior neural fate by an activation signal, with its subsequent regionalization along the anteroposterior (AP) axis regulated by a graded transforming activity, leading to a properly patterned forebrain, midbrain, hindbrain and spinal cord. The activation(More)
A third member of the murine caudal-like gene family, Cdx-4, has been isolated. In situ hybridization and immunohistochemistry have been used to study the localization of mRNA and protein during murine embryogenesis. Cdx-4 is expressed transiently from 7.0 d.p.c. (days post coitum) until 10 d.p.c., starting at the beginning of gastrulation (7.0-7.5 d.p.c.)(More)
The skeletal muscles of the limbs develop from myogenic progenitors that originate in the paraxial mesoderm and migrate into the limb-bud mesenchyme. Among the genes known to be important for muscle development in mammalian embryos are those encoding the basic helix-loop-helix (bHLH) myogenic regulatory factors (MRFs; MyoD, Myf5, myogenin and MRF4) and(More)
Injection of RNA encoding BMP-4 into the early Xenopus embryo suppresses formation of dorsal and anterior cell types. To understand this phenomenon, it is necessary to know the stage at which BMP-4 acts. In this paper, we present three lines of evidence showing that BMP-4 misexpression has no effect on the initial steps of mesoderm induction, either dorsal(More)
Vertebrates have characteristic and conserved left-right (L-R) visceral asymmetries, for example the left-sided heart. In humans, alterations of L-R development can have serious clinical implications, including cardiac defects. Although little is known about how the embryonic L-R axis is established, a recent study in the chick embryo revealed L-R(More)
Definition of cell fates along the dorso-ventral axis depends on an antagonistic relationship between ventralizing transforming growth factor-beta superfamily members, the bone morphogenetic proteins and factors secreted from the dorsal organizer, such as Noggin and Chordin. The extracellular binding of the last group to the bone morphogenetic proteins(More)
An association has been noted previously in chick, mouse and frog embryos between asymmetric nodal-related gene expression and embryonic situs, implying an evolutionarily conserved role in left-right specification. Of the four Xenopus nodal-related genes expressed during gastrulation, only Xnr-1 is re-expressed unilaterally in the left lateral plate(More)
cDNAs encoded by the mouse homolog (Lim-1) of the Xenopus LIM-class homeobox gene Xlim-1 have been isolated from an 8.5-day mouse embryo cDNA library. Nucleotide and deduced amino acid sequences show a high degree of identity with Xlim-1 in the LIM and homeodomains, and 85% identity over the whole protein. An interspecific back-cross has been used to show(More)