ROLE OF XHOX HOMEOBOX GENES IN XENOPUS DEVELOPMENT

XHOX 同源盒基因在爪蟾发育中的作用

• 批准号: 3327364
• 负责人: RICHARD A HARVEY
• 金额: $ 6.86万
• 依托单位: WALTER AND ELIZA HALL INST MEDICAL RES
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-09-01 至 1992-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3327364
• 关键词: DNA binding protein; Xenopus; chimeric proteins; developmental genetics; early embryonic stage; ectoderm; gene expression; genetic manipulation; genetic promoter element; homeobox genes; immunocytochemistry; laboratory rabbit; mutant; myogenesis; nonmammalian vertebrate embryology; transcription factor

A recent focus of development biology has been to isolate and study genes through to make critical decisions of cell fate and patterning in embryogenesis. Genetic studies in Drosophila indicate that genes containing the homeobox DNA-binding motif participate in such decisions.Other genes such as the vertebrate Myo-D gene, also have the compelling properties of developmental regulators. We propose to study regional specification and pattern formation in Xenopus embryos using as a focus the Xhox-1 homeobox genes and the Myo-D gene. In previous work we devised an overexpression assay to address the function of the Xhox-1A gene and demonstrated that it is likely to be involved in somite formation. Somitogenesis is a primary segmentation event which shapes the vertebrate body play. This finding is significant because it is the very first indication of a function for a vertebrate homeobox gene and it fulfills the broad expectation that homeobox genes will participate in critical developmental events. We propose to study further the role of Xhox-1A and a linked gene. Xhox-1B, in somite formation. We will use antibodies to investigate at cellular resolution the normal expression pattern of these genes. Furthermore, we will design dominant-acting mutants of the Xhox-1 genes which will be used to antagonize the action of the endogenous genes and thus perturb somitogenesis in new ways. We will also approach homeobox gene function at the biochemical level by studying the binding of Xhox-1A protein to DNA. We believe that in the long term this biochemical approach will reveal how stable developmental changes are affected. In Xenopus, most of the somite tissue becomes muscle. Nothing is known about how the patterning of muscle tissue (somitogenesis) meshes with commitment to the muscle lineage. Evidence suggests that the Myo-D gene is instructive in this commitment step. We will characterize the expression of the Xenopus Myo-D during early development and attempt to devise functional assays to test whether Myo-D gene expression can commit multipotent, embryonic ectoderm directly into the muscle lineage. These experiments are designed to investigate specific examples of cell commitment and patterning in vertebrate development. In addition, we will take a more general approach to the fundamental problem of how regional specification occurs in embryos. We will screen a pre-gastrulation cDNA library with probes for developmentally interesting genes such as other homeobox genes, believing that many of them will show restricted spatial expression and will indicate zones of cell commitment at early stages. The strength of this proposal lies in the fact that we already have a functional assay for the homeobox genes that we study and in the fact that we can relate these studies to the wealth of cellular and developmental information available for Xenopus embryos.

发育生物学最近的一个焦点是分离和研究基因 通过对细胞命运和模式做出关键决定 胚胎发生。果蝇的遗传学研究表明，基因 含有同源盒 DNA 结合基序参与这样的 其他基因，例如脊椎动物的 Myo-D 基因，也具有 发育调节因子的引人注目的特性。我们建议学习 非洲爪蟾胚胎的区域规范和模式形成 重点关注 Xhox-1 同源盒基因和 Myo-D 基因。 在之前的工作中，我们设计了一种过表达测定法来解决 Xhox-1A 基因的功能并证明它可能是 参与体节形成。体节发生是主要的分割 塑造脊椎动物身体活动的事件。这一发现意义重大 因为这是脊椎动物功能的第一个迹象 同源盒基因，它满足了同源盒基因的广泛期望 将参与关键的发展事件。我们建议学习 进一步研究 Xhox-1A 和连锁基因的作用。 Xhox-1B，位于体节 形成。我们将使用抗体以细胞分辨率进行研究 这些基因的正常表达模式。此外，我们还将设计 Xhox-1 基因的显性突变体将用于 拮抗内源基因的作用，从而扰乱 以新的方式进行体节发生。我们还将研究同源框基因功能 通过研究 Xhox-1A 蛋白与 脱氧核糖核酸。我们相信，从长远来看，这种生化方法将 揭示稳定的发育变化是如何受到影响的。 在爪蟾中，大部分体节组织变成肌肉。什么都不知道 关于肌肉组织的模式（体节发生）如何与 对肌肉谱系的承诺。有证据表明 Myo-D 基因 在这一承诺步骤中具有指导意义。我们将表征 Xenopus Myo-D 在早期发育过程中的表达并尝试 设计功能测定法来测试 Myo-D 基因表达是否可以发挥作用 多能的胚胎外胚层直接进入肌肉谱系。 这些实验旨在研究细胞的具体例子 脊椎动物发育的承诺和模式。此外，我们将 对区域如何发展这一根本问题采取更普遍的方法 规范发生在胚胎中。我们将筛选原肠胚形成前 cDNA 带有针对发育感兴趣的基因（例如其他基因）的探针的文库 同源框基因，相信其中许多将显示出受限的空间 表达并将指示早期阶段的细胞定向区域。 该提案的优点在于我们已经有了一个 我们研究的同源框基因的功能分析，事实上 我们可以将这些研究与丰富的细胞和 非洲爪蟾胚胎的发育信息。