GENETICS OF EPIDERMAL PATTERNING IN C ELEGANS EMBRYOS

这项研究的主要目标是了解单个上皮细胞如何 薄片在胚胎发育过程中形成图案，变成离散的 不同细胞类型的结构域。线虫的表皮 秀丽隐杆线虫，将其作为一种简单的模型上皮进行研究。 在此过程中，这种上皮细胞细分为三种主要细胞亚型 胚胎发生。将特别强调以下机制： 指定了这些子类型中的哪一个，即Seam单元格。 因为这里研究的突变会导致胚胎的严重缺陷 发展，这些研究应该成为人类生育的模式 缺陷。此外，通过检测导致细胞增殖的基因， 胚胎细胞选择特定的分化路径，这项工作 应该有助于我们理解正常的 在恶性肿瘤中，生长和分化的控制被废除 转化的细胞，导致癌症。 合子表达的基因zen-3对正常的表皮是必不可少的。 胚胎发育过程中缝隙细胞的图案化和分化。 6个zen-3突变体的花纹和缝隙分化缺陷将是 用表皮特异性抗体进行免疫荧光研究 描述由活动中的变化引起的缺陷范围 禅宗3号的。银杏叶上皮细胞的发育 具有代表性的ZEN-3突变体之后将进行细胞谱系分析 使用视频系统记录整个过程中所有单元的位置 胚胎发生。为了评估ZEN-3功能的作用时间， Tzen-3突变体的温度敏感期将是 下定决心。一种携带ZEN-3(+)的酵母人工染色体 函数将被标识并融合到携带 细胞自主标记。这种融合的复制将用于定义 通过执行遗传镶嵌而需要ZEN-3的细胞 分析。启动与Seam相关的其他基因的研究 规格和表皮图案，现有的55个集合 将对表皮发育有缺陷的突变株进行筛选 免疫荧光和时间推移。此屏幕将用于缩小范围 关于一个或几个基因的研究，以供未来的详细研究。最后，激光 早期卵裂球的切除将在野生型胚胎上进行 鉴定Seam细胞分化所需的细胞。这些实验 将最终导致对表皮图案的阐明 分子分辨率。

The broad goal of this research is to learn how a single epithelial cell sheet becomes patterned during embryonic development into discrete domains of different cell types. The epidermis of the nematode Caenorhabditis elegans, will be studied as a simple model epithelium. This epithelium becomes subdivided into three major cell subtypes during embryogenesis. Particular emphasis will be placed on the mechanisms by which one of these subtypes, the seam cells, are specified. Because the mutations studied here lead to severe defects in embryonic development, these studies should serve as models for human birth defects. In addition, by examining genes that cause proliferating embryonic cells to select particular paths of differentiation, this work should contribute to our understanding of mechanisms by which normal controls of growth and differentiation are abrogated in malignantly transformed cells, resulting in cancer. The zygotically expressed gene, zen-3, is essential for normal epidermal patterning and differentiation of seam cells during embryogenesis. Patterning and seam differentiation defects in six zen-3 mutants will be studied by immunofluorescence with epidermis-specific antibodies to characterize the range of defects resulting from changes in the activity of zen-3. The development of individual epidermal cells in a representative zen-3 mutant will be followed by cell lineage analysis using a video system that records the position of all cells throughout embryogenesis. To assess the time of action of zen-3 function, the temperature-sensitive (ts) period of a ts zen-3 mutant will be determined. A yeast artificial chromosome that carries zen-3 (+) function will be identified and fused to a duplication carrying a cell-autonomous marker. This fused duplication will be used to define the cells in which zen-3 is required by performing genetic mosaic analysis. To initiate studies of other genes involved in seam specification and epidermal patterning, an existing collection of 55 mutants defective in epidermal development will be screened by immunofluorescence and time-lapse. This screen will be used to narrow in on one or a few genes for future detailed investigations. Finally, laser ablations of early blastomeres will be performed on wild-type embryos to identify cells required for seam cell differentiation. These experiments will ultimately lead to the elucidation of epidermal patterning at molecular resolution.