In a large scale screen for mutants with defects in the embryonic development of the zebrafish we identified mutations in four genes,floating head (flh), momo (mom), no tail (ntl), and doc, that are required for early notochord formation. Mutations in flh and ntl have been described previously, while mom and doc are newly identified genes. Mutant mom embryos lack a notochord in the trunk, and t...

The LIM class homeodomain protein Xlim-1 is specifically expressed in the organizer and later in the notochord in Xenopus. By seeking genes which are activated by Xlim-1 in animal caps, we isolated a gene which encodes a protein highly homologous to human PA26-T2, a p53-inducible nuclear factor, which we refer to as XPA26. Northern blot analysis showed that maternal transcripts of XPA26 are det...

Hensen's node in the chick embryo contains prospective notochord cells in a V-shaped midline region of the mesoderm, and prospective medial half somite cells in the lateral portions of the node mesoderm, whilst lateral somite cells are derived from the rostral part of the primitive streak (Selleck and Stern, Development 112, 615-626, 1991). In the present study, we have investigated the commitm...

The orientation of developing myoblasts extending a bipolar axis in the presence of explanted myoblasts or whole notochord has been studied in vitro. Myoblasts tended to elongate perpendicular to the lines of diffusion of substances from these tissues. A slow-release source of agar impregnated with medium conditioned by segmented somitic myoblast or notochord also caused myoblasts to elongate p...

In the developing embryo, cell-cell signalling is necessary for tissue patterning and structural organization. During midline development, the notochord plays roles in the patterning of its surrounding tissues while forming the axial structure; however, how these patterning and structural roles are coordinated remains elusive. Here, we identify a mechanism by which Notch signalling regulates th...

The embryonic vertebral column is derived from the unsegmented axial mesenchyme surrounding the notochord, and its development and differentiation are influenced by the notochord. The role of cartilage in determining the ultimate pattern of the segmental skeleton has been well documented, but a gene whose segmental expression corresponds to the pattern of the developing skeleton has yet to be i...

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 cultur...

Previous studies have demonstrated that the neural tube/notochord complex is required for skeletal muscle development within somites. In order to explore the localization of myogenic inducing signals within the neural tube, dorsal or ventral neural tube halves were cultured in contact with single somites or pieces of segmental plate mesoderm. Somites and segmental plates cultured with the dorsa...

Back pain related to intervertebral disc degeneration is the most common musculoskeletal problem, with a lifetime prevalence of 82%. The lack of effective treatment for this widespread problem is directly related to our limited understanding of disc development, maintenance and degeneration. The aim of this study was to determine the developmental origins of nucleus pulposus cells within the in...

The origin of chordates has been debated for more than a century, with one key issue being the emergence of the notochord. In vertebrates, the notochord develops by convergence and extension of the chordamesoderm, a population of midline cells of unique molecular identity. We identify a population of mesodermal cells in a developing invertebrate, the marine annelid Platynereis dumerilii, that c...