The activin signaling pathway promotes differentiation of dI3 interneurons in the spinal neural tube.

The generation of the appropriate types and numbers of mature neurons during the development of the spinal cord requires the careful coordination of patterning, proliferation, and differentiation. In the dorsal neural tube, this coordination is achieved by the combined action of multiple ligands of both the Wnt and TGF-beta families, and their effectors, such as the bHLH proteins. TGF-beta signaling acting through the BMP receptors is necessary for the generation of several dorsal interneuron types.

Coordinate regulation of neural tube patterning and proliferation by TGFbeta and WNT activity.

Pattern formation and growth must be tightly coupled during embryonic development. In vertebrates, however, little is known of the molecules that serve to link these two processes. Here we show that bone morphogenetic proteins (BMP) coordinate the acquisition of pattern information and the stimulation of proliferation in the embryonic spinal neural tube.

Plasmid-based short-hairpin RNA interference in the chicken embryo.

The chicken neural tube serves as an ideal model for new techniques to alter gene expression. We show that short-hairpin RNA delivered by a plasmid vector can effectively knock down expression of both exogenous and endogenous genes in the chicken neural tube. We also assay the effects of short-hairpin RNA on the interferon response and find no difference between electroporation of a control plasmid and a short-hairpin RNA plasmid.

Cell polarity pathways converge and extend to regulate neural tube closure.

Neural tube defects, such as spinabifida, craniorachischisis and anencephaly, are some of the most common birth defects in humans. Recent studies in mouse model systems suggest that craniorachischisis is associated with mutations in genes that regulate cell polarity. Using Xenopus as a model system, Wallingford and Harland have now shed light on the mechanism by which these pathways affect neural tube closure.