GENETIC CONTROL OF SYMMETRY IN THE DROSOPHILA EYE

这个项目的目标是了解分子基础 果蝇复眼背腹模式的建立 在每个单位眼中，小眼由8个感光细胞排列成一个 不对称的梯形图案。背侧眼球视野呈镜面对称 关于腹侧视野；光感受器簇是 赤道两极在相反的方向上，中线 连接背侧-腹侧眼区。背部腹侧镜像为 建立为光感受器簇顺时针旋转90度或 逆时针方向，取决于每一个的背腹极 集群。只有几个基因在规范中被发现 这些机制。 这项研究将使用分子和经典遗传学来表征一种 显示背部特异性白色+基因的增强子陷阱菌株B1-12 在眼睛和其他两个参与旋转的基因中的表达 进程，尼莫和轮盘赌。还将进行系统的突变筛选 分离出更多的突变体来剖析其遗传途径 背腹模式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)我们将分离出一名 候选背部特异基因B1-12，表征B1-12的眼部表型 由不精确的切除事件产生的突变，(2)我们将确定 通过分离与背腹模式有关的其他基因 破坏B1-12背部特异模式的突变和通过 用于背侧、腹侧或赤道特异性表达的增强子陷阱筛选 (3)我们将使用FRT/FLP进行系统的遗传筛查 重组系统用于识别控制背腹侧极性的基因 (4)我们将分离轮盘赌下游的基因 以及(5)我们将寻找基因 NEMO突变的修饰物来识别相互作用的基因，并使用 酵母双杂交系统分离编码相互作用蛋白的基因。 两侧对称和不对称的两极是常见的 大多数生物体中的身体及其部分。问题是宿舍生如何- 腹极是在分子和细胞水平上建立的 与内脏内翻现象有关，翻转内脏 哺乳动物的内脏不对称，这是异常的结果 极性的测定。基本的机制，可能还有基因 参与组织极性可能在结构和功能上是保守的 在果蝇和哺乳动物之间。考虑到强大的遗传方法 在果蝇中可用，有人建议将其作为模式生物 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.