Functional analysis of MEN1 in Drosophila model

描述(由申请人提供)：分析导致遗传性癌症易感性的基因及其作用途径，对于洞察细胞生长和分化的正常调控至关重要。MEN1是一种遗传性疾病，以甲状旁腺、胰岛和脑下垂体肿瘤为特征。负责基因编码一种功能未知的核蛋白--“薄荷素”。 最近，伯克利基因组计划发现了一种与MEN1同源的果蝇。在我的实验室的初步研究中，该基因在各种发育中的组织中表达，包括苍蝇的主要内分泌器官。我们创造了过表达果蝇MEN1的转基因果蝇，发现在外胚层Td中的表达与果蝇Jun和Fos的突变引起的表型相似。遗传修饰物研究表明MEN1与Jun和Fos之间存在相互作用。除了转基因果蝇外，我们现在还创造了果蝇MEN1的功能突变。我结合其他报告的初步结果表明，薄荷素在几种不同的信号转导途径以及许多不同的细胞和发育过程中发挥作用。生化研究表明，Menin与Jund、Smad3、NF-kB、NM23和Pem之间存在相互作用。Menin与多种转录因子形成复合物，但本身并不与DNA结合，这一事实表明，它可能是一种转录共调节因子。在果蝇模型中可能进行的进一步遗传操作将使我能够研究薄荷素在任何发育阶段控制细胞分化和增殖的功能。在这种无脊椎动物有机体中筛选遗传修饰物，并利用微阵列进行有益的表达，将有助于确定薄荷素发挥作用的遗传途径，以及在其中每一种相互作用都很重要的生理背景。这项提案中概述的实验将确定果蝇脑膜素是否作为辅助抑制分子发挥作用，密切研究脑膜素在体细胞组织和生殖系发育中的作用，并确定脑膜素的丢失是否会导致细胞过度增殖。我预计，在果蝇模型中发现的许多或所有脑膜素的细胞功能将与哺乳动物的对应。我未来的计划包括基于在苍蝇中发现的相互作用，在老鼠身上进行有针对性的遗传相互作用研究。确定哪些遗传途径在脑膜相关肿瘤萎缩症中起重要作用，为合理的药物治疗奠定了基础。

DESCRIPTION (provided by applicant): Analysis of the genes responsible for hereditary cancer predisposition and the pathways in which they act has been critically important in providing insight into the normal regulation of cell growth and differentiation. MEN1 is a hereditary disorder characterized by tumors of the parathyroids, pancreatic islets, and pituitary gland. The responsible gene encodes a nuclear protein, "menin", of unknown function. A Drosophila homolog of MEN1 was recently identified by the Berkeley Genome Project. In preliminary studies my laboratory showed that the gene is expressed in a variety of developing tissues including the major endocrine organs of the fly. We created transgenic flies with overexpression of Drosophila MEN1 and found that expression in the ectoderm Td a phenotype similar to that caused by mutations of Drosophila Jun. Genetic modifier studies showed an interaction between MEN1 and both Jun and Fos. In addition to the transgenic flies, we have now created a toss-of-function mutant of Drosophila MEN1. My preliminary results in conjunction with other reports indicate that menin acts in several different signal transduction pathways and in many different cellular and developmental processes. Biochemical studies have shown an interaction between menin and JunD, SMAD3, NF-kB, NM23 and Pem The fact that menin complexes with several transcription factors but does not itself bind DNA suggests that it may be a transcriptional co-modulator. Further genetic manipulations possible in a Drosophila model will allow me to study the function of menin in control of cellular differentiation and proliferation at any developmental stage. Genetic modifier screens in this invertebrate organism and expression profiting with microarrays wilt help identify the genetic pathways in which menin functions and the physiologic context in which each interaction is important. The experiments outlined in this proposal will determine if Drosophila menin functions as a co-repressor molecule, shed tight on the role of menin in development of somatic tissues and the germline and determine whether loss of menin leads to a hyperproliferative cellular phenotype I anticipate that many or all of the cellular functions of menin found in the Drosophila model will have counterparts in mammals. My future plans include targeted genetic interaction studies in the mouse, based on interactions discovered in the fly. Determining which genetic pathways are important in menin-related neoplasia wilt lay the groundwork for rational medical therapy.