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

该项目的长期目标是了解控制脊索发育的基因的作用模式。脊索是形成旁轴中胚层和神经管的重要信号中心。因此，脊索发育受扰会导致轴骨畸形或发育不全以及脊髓缺陷。虽然脊索的功能已经确定，但人们对控制其发育和完整性的基因知之甚少。对特定影响脊索发育和完整性的突变的分析是识别此类基因的关键。本研究的重点是对我们在前期研究中分离到的SD候选基因Chordal进行分子遗传学分析。丹佛的短尾(SD)突变影响尾芽形成脊索，并导致脊索沿其全长完全解体，表明受影响的基因对脊索的发育和维持是必不可少的。这项建议的目标是在体外和体内表征脊索及其功能，并检验脊索是受SD突变影响的基因的假设。这将通过鉴定脊索基因及其转录本及其在正常胚胎发育和成年组织中的表达，以及在SD突变胚胎中的表达，鉴定脊索蛋白(S)及其生化特性和相互作用伙伴，以及通过产生脊索功能等位基因的丧失来实现。总之，这项研究的结果有望阐明一个新基因的功能，该基因可能对脊索发育至关重要，并进一步了解控制脊索发育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.