STEPS CONTROLLING GENE EXPRESSION

果蝇的胚胎期是一个细胞期 细胞周期和细胞周期的决定和戏剧性转变 抄写。这一阶段与 两栖动物中胚泡的转变表明有一个 一系列涉及细胞周期、转录和 细胞运动是许多早期发育的共同之处 有机体。我们在果蝇身上研究这些事件是因为 将分子分析与遗传分析相结合的潜力 这个系统。我们已经成功地鉴定出四只果蝇 胚胎特异性基因：末端(Ter)、极芽(Pod)、 机缘巧合(Sry)和bsg25A。使用标准的基因筛查 技术以及限制片段长度多态 定位，多线染色体的原位杂交，以及P- 因子介导的转化，我们将鉴定突变的等位基因 每个基因，就像我们对sry基因座的Delta基因所做的那样。 在此过程中，我们将测试ter、Pod和 Bsg25A、HID、斯莱特和施拉夫都是胚胎 接近这些基因的致命性突变并影响 胚胎形态。我们将描述变种人的特征 通过光镜和电子显微镜观察每个基因的表型。TER 该基因编码一个类似TFIIIA的、可能与DNA结合的手指。我们会 使用抗体来询问蛋白质是否存在于细胞核中 并将使用重组DNA方法来设计生产 研究融合蛋白和天然TER蛋白是否与DNA结合 体外培养。如果是这样的话，我们将确定特定的DNA结合序列。我们 将鉴定TER基因的顺式调控序列，并检测 假设基因是自我调节的，并且手指 在这一规定中扮演着重要的角色。我们将测试它的重要性 POD蛋白与FOS的结构相似性结构域 癌基因蛋白的空间表达特征 基因(通过与整个胚胎的原位杂交和抗体 染色)，并询问POD蛋白是核的还是 与细胞骨架有关。我们将准备一种分子 绘制bsg25A基因座的图谱，对其mRNA进行测序，并检查 基因在胚胎中的空间表达。分析了几个问题 这些胚层特异的基因将为深入了解 在调节细胞周期、细胞运动和 发生在胚胎发育早期的细胞承诺。这个 对这些过程的监管与类似事件和 他们的精神错乱，就像他们后来在 在成年生物体中的发育。

The blastoderm stage in Drosophila melanogaster is a time of cell determination and dramatic transitions in the cell cycle and in transcription. The similarities between this stage and the midblastula transition in amphibians suggests that there is a constellation of events involving the cell cycle, transcription and cell movement that is common to the early development of many organisms. We are studying these events in Drosophila because of the potential for integrating molecular with genetic analyses in this system. We have succeeded in identifying four Drosophila blastoderm specific genes: terminus (ter), polebud (pod), serendipity (sry) and bsg25A. Using standard genetic screening techniques, as well as restriction fragment length polymorphism mapping, in situ hybridization to polytene chromosomes, and P- factor mediated transformation, we will identify mutant alleles in each genes, as we have done for the delta gene of the sry locus. In so doing, we will test the relationship between ter, pod and bsg25A, and hid, slater and schlaff, respectively, all embryonic lethal mutations which map close to these genes and affect embryonic morphology. We will characterize the mutant phenotype of each gene by light and electron microscopy. The ter gene encodes a TFIIIA-like, putative DNA-binding finger. We will use antibodies to ask whether the protein is present in the nucleus and will use recombinant DNA methods to engineer the production of fusion and native ter proteins to ask whether it binds DNA in vitro. If so, we will identify specific DNA-binding sequences. We will identify the cis-regulatory sequences of the ter gene, and test the hypothesis that the gene is autoregulatory and that the finger plays a role in this regulation. We will test the significance of domains of structural similarity between the pod protein and fos oncogene protein by characterizing the spatial expression of the gene (by in situ hybridization to whole embryos and antibody staining) and asking whether the pod protein is nuclear or associated with the cytoskeleton. We will prepare a molecular map of the bsg25A locus, sequence its mRNA, and examine the spatial expression of the gene in the embryo. The analysis of these blastoderm-specific genes will provide insight into the unique events in regulation of the cell cycle, cell movement and cell commitment that occurs during early embryogenesis. The regulation of these processes is relevant to similar events and their derangement, as they occur at later times during development and in the adult organism.