In vertebrate embryos, signaling via the beta-catenin protein is known to play an essential role in the induction of the dorsal axis. In its signaling capacity, beta-catenin acts directly to affect target gene transcription, in concert with transcription factors of the TCF/LEF family. We have developed a cell-free in vitro assay for beta-catenin signaling activity that utilizes transcriptionall...

''Chacun d'eux portait sur son dos une e ´norme Chimère'' [Each one of them carried on his back an enormous Chimera] —Baudelaire, Le Spleen de Paris, bk. VI Until the end of the seventeenth century, the monstrous body had a mythological function: A sign from irate gods, the monster (Kapler 1980) is not malformed like Oedipus's twisted foot/fate, it is a prodigious creature whose corporeal forma...

The earliest event in Xenopus development is the dorsal accumulation of nuclear β-catenin under the influence of cytoplasmic determinants displaced by fertilization. In this study, a genome-wide approach was used to examine transcription of the 43,673 genes annotated in the Xenopus laevis genome under a variety of conditions that inhibit or promote formation of the Spemann organizer signaling c...

To address the patterning function of the Bmp2, Bmp4 and Bmp7 growth factors, we designed antisense morpholino oligomers (MO) that block their activity in Xenopus laevis. Bmp4 knockdown was sufficient to rescue the ventralizing effects caused by loss of Chordin activity. Double Bmp4 and Bmp7 knockdown inhibited tail development. Triple Bmp2/Bmp4/Bmp7 depletion further compromised trunk developm...

The appearance of bottle cells at the dorsal vegetal/marginal boundary of Xenopus embryos marks the onset of blastopore formation. The conditions leading to this epithelial activity were investigated by inducing bottle cells ectopically in the animal region with VegT or different members of the transforming growth factor (TGF)-beta family. Morphological studies on the ectopic bottle cells indic...

The intermediate mesoderm (IM) is the embryonic source of all kidney tissue in vertebrates. The factors that regulate the formation of the IM are not yet well understood. Through investigations in the chick embryo, the current study identifies and characterizes Vg1/Nodal signaling (henceforth referred to as 'Nodal-like signaling') as a novel regulator of IM formation. Excess Nodal-like signalin...

The advantages and disadvantages of the use of direct geometry spectrometers for molecular spectroscopy and catalysis studies are described. We show that both direct and indirect geometry INS spectrometers are important tools for the study of industrially relevant areas such as catalysis, proton conductors and gas separation. We propose a novel hybrid instrument, Cerberus, that would offer high...

Avian embryos have a remarkable capacity to regulate: when a pre-primitive streak stage embryo is cut into fragments, each fragment can spontaneously initiate formation of a complete embryonic axis. We investigate the signalling pathways that initiate primitive streak formation and the mechanisms that ensure that only a single axis normally forms. As reported previously, an ectopic primitive st...