Role of Drosophila Bunched Protein Isoforms in Regulating Notch Signaling at Cell Fate Boundaries

B。果蝇成束蛋白异构体在调节Notch信号在细胞命运边界中的作用智力价值在多细胞动物的发育过程中，细胞增殖必须与细胞分化协调，以形成适当的组织。 细胞通过分离成单独的区域（或隔室）并在其边界建立减少细胞混合的区域来协调其活动。 细胞命运边界组织了广泛组织的图案和形态发生，包括果蝇的眼赤道和翅缘，以及脊椎动物的顶端外胚层脊，体节和后脑菱形节。果蝇聚束基因是高度保守的TSC-22/GILZ转录因子家族的成员，在卵子发生过程中建立上皮细胞的命运边界。 bunched编码三种不同的蛋白质同种型，其结构特征对应于小鼠TSC-22基因的三种同种型，其受长距离形态发生素调节以设定细胞命运边界的位置。 Bunched 1亚型在细胞命运边界调节细胞亲和力和短距离Notch信号，该边界与蝇卵壳的关键结构特征一致，即鳃盖领。以及（2）表征三种Bunched同种型之间的相互作用如何影响细胞命运。 这个建议的长期目标是阐明复杂的，保守的机制，细胞的命运boundaries是established.Broader ImpactA发育中的一个基本问题是如何组织细分发生的基因，最初表达在广泛的，重叠的域，调节下游基因的表达，建立一个明确的模式。 TSC-22蛋白家族在动物中广泛保守，但广泛的哺乳动物组织培养研究尚未阐明其发育功能。 提出的实验将提供基本的见解成束蛋白异构体如何相互作用，以调节基因转录在形成细胞命运的边界，并照亮类似的调节过程中的四肢，神经系统和其他脊椎动物和无脊椎动物组织。 建议的实验旨在将研究与本科生和研究生的教学和培训计划相结合。对果蝇基因的关注类似于人类TSC-22，一个与几种人类癌症和糖尿病神经病变相关的基因，将向学生传达模型生物的潜力，以阐明发育机制作为理解人类疾病的基础。在这些目标中详细描述的逻辑系列实验可分为适合研究生的较大项目和适合本科生的较小项目。 这里概述的工作将补充本科生的研究，包括扩展研究和夏季研究的学者计划（Sapere和Sapere Vedere奖学金）和博士学位。培训计划。本计画将加强以下教学：（1）本科生之发育生物学及研究生程度之进阶细胞生物学，强调以果蝇、C.和酵母作为基因组工具。 这项工作将进一步发展发育生物学实验室课程，部分基于这里计划的遗传实验。

B. PROJECT SUMMARYRole of Drosophila Bunched protein isoforms in regulating Notch signaling at cell fate boundaries Intellectual meritDuring development of a multicellular animal, cell proliferation must be orchestrated with cell differentiation for proper tissue formation. Cells coordinate their activities by segregating into separate domains - or compartments - and establishing regions of reduced cell mixing at their boundaries. Cell fate boundaries organize patterning and morphogenesis of a wide range of tissues, including the eye equator and wing margin in Drosophila, and the apical ectodermal ridge, somite and hindbrain rhombomeres in vertebrates. Little is known about the mechanisms that generate cell fate boundaries and translate compartment boundaries into the structural features of mature tissue.The Drosophila bunched gene, a member of the highly conserved TSC-22/GILZ family of transcription factors, establishes an epithelial cell fate boundary during oogenesis. bunched, which encodes three distinct protein isoforms whose structural features correspond to three isoforms of the mouse TSC-22 gene, is regulated by long-range morphogens to set the position of a cell fate boundary. The Bunched1 isoform regulates cell affinities and short-range Notch signaling at a cell fate boundary that coincides with a key structural feature of the fly eggshell, the collar of the operculum.Using a simple model tissue and applying powerful molecular and genetic approaches, the goals of this proposal are to: (1) determine how long-range morphogen signaling is refined to short-range Notch activation via Bunched1; and (2) characterize how interactions among the three Bunched isoforms pattern cell fates. The long term goal of this proposal is to elucidate the complex, conserved mechanism by which cell fate boundaries are established.Broader ImpactA fundamental question in development is how tissue subdivision occurs by genes, initially expressed in broad, overlapping domains, which regulate the expression of downstream genes to establish a defined pattern. The TSC-22 family of proteins is widely conserved in animals but extensive mammalian tissue culture studies have shed no light on their developmental function. Experiments proposed will give basic insights into how Bunched protein isoforms interact to regulate gene transcription at forming cell fate boundaries and illuminate similar regulatory processes in limbs, nervous system and other vertebrate and invertebrate tissues. Experiments proposed are designed to integrate research with a program of teaching and training undergraduate and graduate students. The focus on a Drosophila gene similar to human TSC-22, a gene associated with several human cancers and diabetic neuropathy, will convey to students the potential of model organisms to elucidate developmental mechanisms as a basis to understand human disease. The logical series of experiments detailed in these Aims are divisible into larger projects suitable for graduate students and smaller projects appropriate for undergraduates. Work outlined here will complement undergraduate research, including scholars programs for extended research and summer research (SEARCH and Sapere Vedere scholarships) and the Ph.D. training program. This project will enhance teaching: (1) Developmental Biology for undergraduates and Advanced Cell Biology, a graduate level course emphasizing the use of animal model systems like Drosophila, C. elegans, and yeast as genomic tools. This work will further development of a lab course for Developmental Biology, based in part on the genetic experiments planned here.