GENETIC CONTROL OF SYMMETRY IN THE DROSOPHILA EYE

该项目的目标是了解 果蝇复眼背腹模式的建立。 在每个单位眼中，小眼，8个感光细胞排列成一个 不对称梯形图案。背侧眼区呈镜像对称 相对于腹侧场;光感受器簇是 在赤道上以相反的方向极化， 连接着眼的背腹侧背腹镜像是 当感光器簇顺时针旋转90度时建立， 逆时针方向，取决于每个的背腹极性 集群只有少数基因已被确定在规格的 这些机制。 这项研究将使用分子和经典遗传学来表征 增强子捕获菌株B1-12，其显示背特异性白色+基因 和另外两个参与旋转的基因 过程，尼莫和轮盘赌。还将进行系统的突变体筛选 分离出更多的突变体，以剖析遗传途径， 背腹图案的形成和随后的旋转 光感受器簇。 这项建议的具体目的如下：（1）我们将隔离一个 候选背部特异性基因B1-12，表征B1-12的眼睛表型 突变产生的不精确切除事件，（2）我们将确定 另外的基因参与的背腹模式的隔离， 突变破坏B1-12的背特异性模式， 增强子陷阱筛选背侧、腹侧或赤道特异性表达 （3）利用FRT/FLP进行系统的遗传筛选 重组系统来鉴定控制背腹极性的基因 （4）我们将分离roulette，一个下游基因， （5）我们将寻找nemo在旋转途径中的遗传学基础。 nemo突变的修饰符，以确定相互作用的基因，并使用 酵母双杂交系统分离编码相互作用蛋白的基因。 双边对称和非对称极性在以下模式中很常见： 大多数生物体的身体及其部分。问题是背部- 腹极性是建立在分子和细胞的levy， 与内脏反位现象有关， 在哺乳动物中观察到的内脏不对称，这是由于异常的 极性的确定。基本的机制，可能还有基因 在结构和功能上是保守的 果蝇和哺乳动物之间的区别鉴于强大的遗传方法 在果蝇中可用，建议将其用作模式生物， 分析这些基本机制。

The goal of this project is to understand the molecular basis for the establishment of the dorsoventral pattern in the Drosophila compound eye. In each unit eye, the ommatidium, 8 photoreceptor cells are arranged in an asymmetric trapezoidal pattern. The dorsal eye field is in mirror symmetry with respect to the ventral field; the photoreceptor clusters are polarized in opposite directions across the equator, a midline that interfaces the dorso-ventral eye fields. The dorso-ventral mirror image is established as the photoreceptor clusters rotate 90 degrees clockwise or counter-clockwise, depending on the dorso-ventral polarity of each cluster. Only a few genes have been identified in the specification of these mechanisms. This study will use molecular and classical genetics to characterize an enhancer trap strain B1-12 that shows dorsal-specific white+ gene expression in the eye and two other genes involved in the rotation process, nemo and roulette. Systematic mutant screens will also be carried out to isolate additional mutants to dissect the genetic pathway for dorso-ventral pattern formation and the following rotation of photoreceptor clusters. The specific aims of this proposal are as follows: (1) We will isolate a candidate dorsal-specific gene B1-12, characterize eye phenotypes of B1-12 mutations produced by imprecise excision events, (2) We will identify additional genes involved in the dorso-ventral pattern by isolation of mutations that disrupt the dorsal-specific pattern of B1-12 and by enhancer trap screen for dorsal-, ventral-, or equator-specific expression of w+, (3) We will carry out a systematic genetic screen using the FRT/FLP recombination system to identify genes that control dorso-ventral polarity of photoreceptor clusters, (4) We will isolate roulette, a gene downstream of nemo in the rotation pathway, and (5) We will search for genetic modifiers of nemo mutation to identify interacting genes, and use the yeast two-hybrid system to isolate genes encoding interacting proteins. Bilateral symmetry and asymmetric polarity are common in the patterns of the body and its parts in most organisms. The problem of how the dorso- ventral polarity is established at the molecular and cellular levy is relevant to the phenomenon of situs inversus viscerum, the reversal of visceral asymmetry seen in mammals, which occurs as a result of abnormal determination of polarity. The basic mechanisms, and possibly the genes involved in tissue polarity may be structurally and functionally conserved between Drosophila and mammals. Given the powerful genetic methods available in Drosophila, it is proposed to use it as model organism to analyze these basic mechanisms.