Salivary Gland Genetic Markers

在果蝇胚胎中，唾液腺是由唇节腹侧的细胞增厚形成的。在胎盘形成后，其细胞内陷形成一个简单的管状腺。在三个小时内，腺体的细胞已经分化，并产生丰富的分泌产物。这个器官发生的简单例子提供了机会来研究建立胚胎整体模式的基因和那些指导组织特定发育的基因之间的相互作用。贝肯多夫博士的实验侧重于胚胎模式形成基因在选择唾液安慰剂的位置和启动唾液腺发育方面的作用。目前这项提议的目标是确定在模式形成基因下游起作用的其他基因，以指导腺体的形态发生和分化。将使用三种独立的方法来识别这些新基因：分析增强子陷阱系，筛选唾液缺陷的缺失突变胚胎，以及寻找For Head基因编码的转录因子的下游靶点。这些方法应该会识别一组新的基因，帮助他描述唾液发育的具体步骤。由于最初的确定和分化之间的时间很短，他希望最终能识别出唾液发育中的许多(如果不是全部)干预步骤。

In Drosophila embryos, salivary glands arise from a thickened placode of cells in the ventral part of the labial segment. After the placode forms, its cells are invaginated to form a simple tubular gland. Within three hours the cells of the gland are already differentiated and producing abundant, secreted products. This simple example of organogenesis provides opportunities to examine the interaction between genes that establish the overall pattern of the embryo and those that direct tissue specific development. Dr. Beckendorf's experiments have focussed on the role of embryonic pattern forming genes in choosing the location of the salivary placodes and initiation salivary gland development. The goal of the current proposal is to identify additional genes that act downstream from the pattern forming genes to direct the morphogenesis and differentiation of the glands. Three independent approaches will be used to identify these new genes: analyzing enhancer trap lines, screening deficiency mutant embryos for salivary defects, and searching for downstream targets of the transcription factor encoded by the for head gene. These methods should identify a new set of genes that will help him characterize specific steps in salivary development. Because of the short time between initial determination and differentiation, he hopes eventually to identify many, if not all, of the intervening steps in salivary development.