Characterisation of chordal, a candidate gene for the Danforth`s short tail mutation

本项目的长期目标是了解控制脊索发育的基因的作用模式。脊索是近轴中胚层和神经管形成的重要信号中心。因此，脊索发育的紊乱导致中轴骨骼的畸形或发育不全以及脊髓的缺陷。虽然脊索的功能已经得到了很好的确定，但对控制其发育和完整性的基因却知之甚少。分析特异性影响脊索发育和完整性的突变是鉴定这些基因的关键。本研究的重点是对Sd的候选基因chordal进行分子遗传学分析。Danforth的短尾（Sd）突变影响脊索从尾芽形成，并导致脊索沿着其整个长度的完全解体，表明受影响的基因是脊索发育和维持所必需的。本研究的目的是在体外和体内研究chordal及其功能，并验证chordal是受Sd突变影响的基因的假设。这将通过以下方式实现：对chordal基因及其转录本的表征，以及其在正常胚胎发生期间和成体组织中的表达，以及在Sd突变胚胎中的表达，对CHORDAL蛋白的生化性质和相互作用伴侣的表征，以及通过产生chordal功能等位基因的缺失。总之，这项研究的结果可以预期阐明一个新的基因的功能可能是至关重要的脊索的发展，并进一步了解控制脊索的发展和完整性的分子机制。

The long-term objective of this project is to understand the mode of action of genes controlling notochord development. The notochord is an essential signalling centre for patterning of the paraxial mesoderm and neural tube. Consequently, perturbed notochord development leads to malformations or agenesis of the axial skeleton and defects of the spinal cord. Whereas the functions of the notochord are well established, little is known about the genes that control its developmental and integrity. The analysis of mutations specifically affecting notochord development and integrity is the key to identify such genes. This proposal focuses on the molecular genetic analysis of chordal, a candidate gene for Sd, which we isolated in our preliminary studies. The Danforth`s short tail (Sd) mutation affects notochord formation from the tail bud, and leads to the complete desintegration of the notochord along its entire length, indicating that the affected gene is essential for notochord development and maintenance. The goals of this proposal are to characterise chordal and its function in vitro and in vivo, and to test the hypothesis that chordal is the gene affected by the Sd mutation. This will be achieved by characterisation of the chordal gene and its transcripts, and its expression during normal embryogenesis and in adult tissues, and in Sd mutant embryos, characterisation of the CHORDAL protein(s) their biochemical properties and interacting partners, and by generating loss of function alleles of chordal. Together, the results of this study can be expected to elucidate the functions of a novel gene likely to be essential for notochord development and further our understanding of the molecular mechanisms controlling notochord development and integrity.