REGULATION OF GENE ACTIVITY IN XENOPUS EARLY DEVELOPMENT

这项工作的长期目标是了解 早期脊椎动物胚胎的基因调控。 胚胎基因表达所必需的顺式作用序列将是 通过将克隆基因显微注射到受精的青蛙卵中来确定。 在鉴定顺式作用元件之后，凝胶阻滞和 DNA酶足迹技术将用于检测和表征 与调节元件相互作用的DNA结合蛋白。 青蛙 系统是这些研究的理想选择，不仅是因为易于 显微注射，但也因为大量的可用性， 胚胎将为DNA的分离提供充足的材料来源， 结合因子 使用这种方法，本文中概述的实验 该提案将在两个重要阶段研究基因调控， 胚胎发育。 首先，从合子中表达的第一个基因的调控 基因组将被检查。 调节这些的反式作用因子 基因被认为是母性的，这项提议中的实验寻求 来分离和鉴定这些母体调节因子。 是 了解母体因素如何调节合子基因很重要 转录，因为这一步是至关重要的成功， 随后的胚胎发育。 第二，在神经发生过程中表达的基因的调节将是 考察 神经诱导是发展心理学的经典问题之一 生物学，但几乎没有人知道它的机制。 中的实验 这一建议将确定负责的顺式和反式作用因素 用于神经细胞粘附的时间和组织特异性调节 分子，（N-CAM），这是第一个基因被转录在 对神经诱导的反应 这些研究将有助于更好地理解转录 在脊椎动物胚胎中的调节。 特别是， 神经基因的调控将有助于全面了解 神经发生，这反过来将是重要的理解， 导致无脑儿和脊柱裂的神经源性缺陷。

The long term aim of this work is to understand the molecular mechanisms of gene regulation in the early vertebrate embryo. The cis-acting sequences essential for embryonic gene expression will be determined by microinjection of cloned genes into fertilized frog eggs. Following identification of the cis-acting elements, gel retardation and DNase footprinting techniques will be used to detect and characterize the DNA-binding proteins that interact with the regulatory elements. The frog system is ideal for these studies, not only because of the ease of microinjection, but also because the availability of very large numbers of embryos will provide an ample source of material for the isolation of DNA- binding factors. Using this approach, the experiments outlined in this proposal will investigate gene regulation at two important stages in embryonic development. Firstly, the regulation of the first genes to be expressed from the zygotic genome will be examined. The trans-acting factors that regulate these genes are expected to be maternal and the experiments in this proposal seek to isolate and characterize these maternal regulatory factors. It is important to understand how maternal factors regulate zygotic gene transcription because this step is critical for the success of all subsequent embryonic development. Secondly, the regulation of genes expressed during neurogenesis will be examined. Neural induction is one of the classic problems of developmental biology but almost nothing is known of its mechanism. The experiments in this proposal will identify the cis and trans-acting factors responsible for the temporal and tissue-specific regulation of the neural cell adhesion molecule, (N-CAM), which is one of the first genes to be transcribed in response to neural induction. These studies will lead to a better understanding of transcriptional regulation in vertebrate embryos. In particular, basic information on the regulation of neural genes will contribute to a complete picture of neurogenesis, and this in turn will be important for understanding the neurogenic defects that result in anencephaly and spina bifida.