The notochord is one of the defining features of chordates. The ascidian notochord is a rod like structure consisting of a single row of 40 cells. The anterior 32 ;primary' notochord cells arise from the A-line (anterior vegetal) blastomeres of the eight-cell stage embryo, whereas the posterior 8 ;secondary' notochord cells arise from the B-line (posterior vegetal) blastomeres of the eight-cell...

The notochord is a defining character of the chordates, and the T-box transcription factor Brachyury has been shown to be required for notochord development in all chordates examined. In the ascidian Ciona intestinalis, at least 44 notochord genes have been identified as bona fide transcriptional targets of Brachyury. We examined the embryonic expression of a subset of murine orthologs of Ciona...

Chordoma is a rare malignant tumor that recapitulates the notochord phenotype and is thought to derive from notochord remnants not correctly regressed during development. Apoptosis is necessary for the proper notochord development in vertebrates, and the apoptotic pathway mediated by Fas and Fasl has been demonstrated to be involved in notochord cells regression. This study was conducted to inv...

The patterning and differentiation of the vertebrate endoderm requires signaling from adjacent tissues. In this report, we demonstrate that signals from the notochord are critical for the development of the hypochord, which is a transient, endodermally derived structure that lies immediately ventral to the notochord in the amphibian and fish embryo. It appears likely that the hypochord is requi...

A main challenge of modern biology is to understand how specific constellations of genes are activated to differentiate cells and give rise to distinct tissues. This study focuses on elucidating how gene expression is initiated in the notochord, an axial structure that provides support and patterning signals to embryos of humans and all other chordates. Although numerous notochord genes have be...

Although cell intercalation driven by non-canonical Wnt/planar cell polarity (PCP) pathway-dependent mediolateral cell polarity is important for notochord morphogenesis, it is likely that multiple mechanisms shape the notochord as it converges and extends. Here we show that the recessive short-tailed Ciona savignyi mutation chongmague (chm) has a novel defect in the formation of a morphological...

The ascidian notochord follows a morphogenetic program that includes convergent extension (C/E), followed by anterior-posterior (A/P) elongation [1-4]. As described here, developing notochord cells show polarity first in the mediolateral (M/L) axis during C/E, and subsequently in the A/P axis during elongation. Previous embryological studies [3] have shown that contact with neighboring tissues ...

Dishevelled signaling plays a critical role in the control of cell intercalation during convergent extension in vertebrates. This study presents evidence that Dishevelled serves a similar function in the Ciona notochord. Embryos transgenic for mutant Dishevelled fail to elongate their tails, and notochord cells fail to intercalate, though notochord cell fates are unaffected. Analysis of mosaic ...

The notochord is the defining structure of the chordates, and has essential roles in vertebrate development. It serves as a source of midline signals that pattern surrounding tissues and as a major skeletal element of the developing embryo. Genetic and embryological studies over the past decade have informed us about the development and function of the notochord. In this review, I discuss the e...

introduction: the aim of this study was evaluate the ability of notochord to induce neural induction and/or differentiation of mouse embryonic stem cell to neuron and motor neuron, respectively. methods: in order to produce embryoid bodies, es cells line royan b1 were grown in suspension in the absence of lif for 4 days. ebs were divided into 4 groups. ebs in group 1 & 2 were further cultured i...