Chondrogenesis; chondromodulin-1 (chm1); Angiogenesis inhibitor; Cartilage; Notochord; Zebra®sh; type II collagen (col2a1); Craniofacial; Otic vesicle; Pectoral ®n; Pharyngeal arch; Maternal transcript; Trabecula; Ethmoid plate; Genetic locus 105 157 chondromodulin-1 (chm1); Angiogenesis inhibitor; Cartilage; Notochord; Zebra®sh; type II collagen (col2a1); Craniofacial; Chondrogenesis; Otic ves...

Programmed cell death (PCD) has been discounted in the ascidian embryo because the descendants of every embryonic cell appear to be present in the tadpole larva. Here we show that apoptotic PCD is initiated in the epidermis and central nervous system (CNS) but not in the endoderm, mesenchyme, muscle, and notochord cells during embryogenesis in molgulid ascidians. However, the affected cells do ...

In ascidian embryos, Brachyury is expressed exclusively in blastomeres of the notochord lineage and play an essential role in the notochord cell differentiation. The genetic cascade leading to the transcriptional activation of Brachyury in A-line notochord cells of Ciona embryos begins with maternally provided beta-catenin, which is essential for endodermal cell specification. beta-catenin dire...

The murine Brachyury (T) gene is required in mesoderm formation. Mutants carrying different T alleles show a graded severity of defects correlated with gene dosage along the body axis. The phenotypes range from shortening of the tail to the malformation of sacral vertebrae in heterozygotes, and to disruption of trunk development and embryonic death in homozygotes. Defects include a severe distu...

The mouse homeobox gene Noto represents the homologue of zebrafish floating head (flh) and is expressed in the organizer node and in the nascent notochord. Previous analyses suggested that Noto is required exclusively for the formation of the caudal part of the notochord. Here, we show that Noto is also essential for node morphogenesis, controlling ciliogenesis in the posterior notochord, and t...

Microsurgical, tissue grafting and in situ hybridization techniques have been used to investigate the role of the neural tube and notochord in the control of the myogenic bHLH genes, QmyoD, Qmyf5, Qmyogenin and the cardiac alpha-actin gene, during somite formation in stage 12 quail embryos. Our results reveal that signals from the axial neural tube/notochord complex control both the activation ...

Transcriptional enhancers are short segments of DNA that switch genes on and off in response to a variety of intrinsic and extrinsic signals. Despite the discovery of the first enhancer more than 30 y ago, the relationship between primary DNA sequence and enhancer activity remains obscure. In particular, the importance of "syntax" (the order, orientation, and spacing of binding sites) is unclea...

As a result of previous research, Ranzi & Tamini (1939) pointed out that the notochord of Amphibian embryos of several species treated with sodium thiocyanate (NaSCN) solutions is larger than the notochord of control embryos. Later, several substances were identified which cause enlargement of the notochord: full data and a complete review of the literature on this subject are given by Ranzi & ...

By using the quail-chicken chimera system, we have previously shown that during development of the spinal cord, floor plate cells are inserted between neural progenitors giving rise to the alar plates. These cells are derived from the regressing Hensen's node or cordoneural hinge (HN-CNH). This common population of HN-CNH cells gives rise to three types of midline descendants: notochord, floor ...

A key issue for understanding the early development of the chordate body plan is how the endoderm induces notochord formation. In the ascidian Ciona, nuclear accumulation of beta-catenin is the first step in the process of endoderm specification. We show that nuclear accumulation of beta-catenin directly activates the gene (Cs-FoxD) for a winged helix/forkhead transcription factor and that this...