Analysis of Ascidian Axis Development

海鞘轴发育分析

• 批准号: 9724094
• 负责人: William Smith
• 金额: $ 20.5万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9724094&HistoricalAwards=false
• 关键词: Analysis; Ascidian; Axis; Development

Smith 9724094 The development of a complex organism, such as a vertebrate, from a fertilized egg is a multi-step process involving the coordinated actions of thousands of genes. In elaboration of the adult form from the egg, mechanisms involving both the segregation of cell fate determinants to specific regions of the developing embryo, and inductive interactions, in which cells communicate to determine the developmental fates of neighboring cells, are found. In this project Dr. Smith will seek to isolate genes that act early in chordate development and which are involved in determining the fates of specific tissues. As a model chordate in these studies, he will use the ascidian Ciona intestinalis. Ciona, which is one of the most primitive of the chordates, has many advantages for study of early chordate development. While ascidians retain the basic body plan common to chordates, they have a fixed lineage in early development, they have very few cells at the larvae stage ((2,300), and they have a genome that is only about 5% the size of a vertebrate. To identify genes which are important for early development in Ciona, an expression cloning strategy will be used. Plasmid cDNA libraries will be made from Ciona gastrula stage embryos. In vitro transcripts from the libraries will be microinjected as pools into 4-cell stage Xenopus embryos. Pools with activity will be identified as those that bring about developmental changes to the Xenopus embryos. Single cDNAs with activity will be isolated by sub-dividing the libraries into progressively smaller pools. The identity of genes isolated by this method will be determined by nucleotide sequencing, and the expression patterns will be determined by in situ hybridization to staged Ciona embryos.

Smith 9724094 从受精卵发育成复杂的生物体（例如脊椎动物）是一个多步骤的过程，涉及数千个基因的协调作用。 在从卵子中发育成成体的过程中，发现了涉及细胞命运决定因素与发育胚胎特定区域的分离以及诱导相互作用（其中细胞进行通信以确定邻近细胞的发育命运）的机制。 在这个项目中，史密斯博士将寻求分离在脊索动物发育早期起作用的基因，这些基因参与决定特定组织的命运。 作为这些研究中的脊索动物模型，他将使用海鞘海鞘。 海鞘是最原始的脊索动物之一，对于研究早期脊索动物的发育具有许多优势。 虽然海鞘保留了脊索动物常见的基本身体结构，但它们在早期发育中具有固定的谱系，它们在幼虫阶段的细胞非常少（（2,300），并且它们的基因组大小仅为脊椎动物的 5% 左右。为了鉴定对 Ciona 早期发育重要的基因，将使用表达克隆策略。将从 Ciona 原肠阶段胚胎中制备质粒 cDNA 文库。 来自文库的转录本将作为池显微注射到 4 细胞阶段爪蟾胚胎中。 具有活性的池将被确定为那些给非洲爪蟾胚胎带来发育变化的池。 通过将文库细分为逐渐更小的库，可以分离出具有活性的单个 cDNA。 通过该方法分离的基因的身份将通过核苷酸测序确定，并且表达模式将通过原位确定 与阶段性玻璃海鞘胚胎杂交。