MOLECULAR GENETICS OF DEVELOPMENT IN DICTYOSTELIUM

该项目的长期目标是分子生物学的应用。 基因工具来理解细胞机制， 分化所必需的过程， 形态发生 目标是识别、分离和 表征基因是必不可少的发展， 盘状网柄菌。 这种真核变形虫生物 为研究细胞功能提供了一个独特的模型系统 参与到发展中来。 在开发过程中， 一群阿米巴细胞分化成多细胞的 由两种细胞类型组成的有机体， 空间组织。 动力，信号传导，粘附， 形态发生信号和细胞类型特异性基因调控 是这种生物体用来 完成其发展计划。 获得的信息 关于这些功能是如何在网骨藻中完成的 为其他生物的类似功能提供了线索。 一种间接的遗传学方法来理解细胞 将采取与发展有关的措施。 的突变体 对发展至关重要的影响进程将是 鉴定，然后分离出突变的基因。 通过这种方式，可以直接处理关键功能元件， 获得。 影响发育的突变体并不是什么新鲜事， 但是分离突变基因的方法 从来都没有。 DNA介导的转化系统 将提供突变和分离这些 基因. 实现这一目标的两种方法是 并行进行。 反义RNA的合成 转化载体将用于抑制 必需的发育基因，或插入到细胞中的载体， 染色体将用于中断基因表达。 无论是 在这种情况下，将筛选大量的转化体， 由转化载体引起的形态发生缺陷。 然后，载体序列将提供用于分离所述载体的手段。 失活基因 这个项目的目的不仅仅是 克隆更多的基因来研究它们的调控。 而是利用 分离重要基因的功能标准， 最终研究基因产物的功能。

The long range goal of this project is the application of molecular genetic tools to understanding the cellular mechanisms and processes that are necessary for differentiation and morphogenesis. The objective is to identify, isolate and characterize genes that are essential for development of Dictoyostelium discoideum. This eucaryotic amoebal organism provides a unique model system for the study of cellular functions that are involved in development. During development, a uniform population of amoebal cells differentiates into a multicellular organism consisting of two cell types with a highly regulated spatial organization. Motility, signal transduction, adhesion, morphogenetic signalling and cell type specific gene regulation are among the fundamental processes utilized by this organism to accomplish its developmental program. The information gained about how these functions are accomplished in Dictyostelium will provide clues to similar functions in other organisms. An indirect genetic approach to understanding the cellular processes related to development will be taken. Mutants that affect processes that are essential for development will be identified, and then the genes that were mutated will be isolated. In this way, a direct handle on critical functional elements can be gained. Mutants that affect development are not new in Dictyostelium, but the means to isolate the mutated genes has never been available. The DNA mediated transformation system will provide the means for both mutating and isolating these genes. Two approaches to accomplishing this goal will be undertaken in parallel. Antisense RNA synthesized from a transformation vector will be used to inhibit expression of essential developmental genes, or a vector that inserts into the chromosome will be used to interrupt gene expression. In both cases, large numbers of transformants will be screened for defects in morphogenesis caused by the transformation vector. The vector sequence will then provide the means for isolating the inactivated gene. The purpose of this project is not simply to clone more genes to study their regulation. Rather it is to use functional criteria to isolate important genes as a means to eventually studying the function of the gene products.