The transcription factor cMyb has well known functions in vertebrate hematopoiesis, but little was known about its distribution or function at early developmental stages. Here, we show that cMyb transcripts are present at the neural plate during gastrulation in chick embryos. cMyb expression then resolves to the cranial neural folds and is maintained in early migrating cranial neural crest cell...

We have identified in Xenopus and in the mouse two highly related genes, Xiro3 and Irx3 respectively, that encode a Drosophila Iroquois-related homeobox transcription factor. Xiro3 in Xenopus and Irx3 in the mouse are expressed early in the prospective neural plate in a subset of neural precursor cells. In Xenopus, injection of Xiro3 mRNA expands the neural tube and induces ectopic neural tissu...

Although Rho-GTPases are well-known regulators of cytoskeletal reorganization, their in vivo distribution and physiological functions have remained elusive. In this study, we found marked apical accumulation of Rho in developing chick embryos undergoing folding of the neural plate during neural tube formation, with similar accumulation of activated myosin II. The timing of accumulation and bioc...

Pax-3 is a paired-type homeobox gene that is specifically expressed in the dorsal and posterior neural tube. We have investigated inductive interactions that initiate Pax-3 transcript expression in the early neural plate. We present several lines of evidence that support a model where Pax-3 expression is initiated by signals that posteriorize the neuraxis, and then secondarily restricted dorsal...

introduction: the native inability of nervous system to regenerate, encourage researchers to consider neural tissue engineering as a potential treatment for spinal cord injuries. considering the suitable characteristics of induced pluripotent stem cells (ipscs) for tissue regeneration applications, in this study we investigated the adhesion, viability and proliferation of neural progenitors (de...

The ascidian neural plate has a grid-like organisation, with six rows and eight columns of aligned cells, generated by a series of stereotypical cell divisions. We have defined unique molecular signatures for each of the eight cells in the posterior-most two rows of the neural plate - rows I and II. Using a combination of morpholino gene knockdown, dominant-negative forms and pharmacological in...

Early in the development of the central nervous system, progenitor cells undergo a shape change, called apical constriction, that triggers the neural plate to form a tubular structure. How apical constriction in the neural plate is controlled and how it contributes to tissue morphogenesis are not fully understood. In this study, we show that intracellular calcium ions (Ca2+) are required for Xe...

We performed in vivo experiments in chick embryos that examined whether application of an exogenous source of Shh protein mimics the ability of the notochord to induce ectopic floor plate cells in the neural tube. Shh cannot act alone to induce a floor plate. However, coapplication of Shh and chordin, a BMP antagonist normally coexpressed with Shh in the notochord, results in a marked switch fr...

Development of the vertebrate eye is dependent on multiple tissue interactions and distinct sets of transcription factors and signalling molecules. The latter are thought to be FGF8 and BMP4, proteins secreted from the neural plate to induce lens formation in the overlying ectoderm. Here we show that the Pbx transcription factor plays a crucial role in this process, as it is required for FGF8 e...

The apical (juxtaluminal) ends of the neural epithelial cells of rat embryos were examined using light and electron microscopy during varying stages of neural tube formation. At the neural-plate stage the apical surfaces exhibit numerous microvilli. At the presomite neurula stage the microvilli are longer and more irregular. Filaments of approximately 40-60 A diameter appear in the apical cytop...