Control of organ formation and morphogenesis during development

我的研究计划的长期目标是了解细胞群如何发育成专门的成人器官。这样的过程需要生长、形态发生和分化的调节。我的团队主要关注果蝇的眼睛，以研究驱动组织规格的细胞信号的许多方面。我们现在将注意力转向细胞信号传导和基因表达调控发生后发生的事件。具体来说，我们感兴趣的是导致最终三维器官形成的机械和结构变化。我们获得的见解很可能广泛适用于了解未分化的上皮细胞如何发育成一个专门的成人器官。我的实验室使用特征良好的，遗传上易处理的果蝇作为模型生物，以了解细胞事件在眼睛形成过程中是如何调节的。成虫组织在幼虫阶段形成称为成虫盘的上皮细胞的离散囊。成年人的眼睛起源于眼盘，包括一个有序的单位眼阵列。眼睛的发育起始于椎间盘的后缘，并以一种称为形态发生沟（MF）的虚拟分化“波”向前移动。MF被视为一条狭窄的细胞带，在顶部和顶部-基底部收缩，这使得它们在上皮中表现为物理凹槽。MF之前的细胞以未分化的增殖状态存在，而MF之后的细胞经历形态发生和分化。因此，MF代表细胞分裂和随后的视网膜分化之间的过渡点。MF的速度受到严格调节，以确保这两种相反的细胞状态之间的适当平衡。迄今为止，很少有研究已经解决了MF进展过程中发生的深刻的细胞形状变化的作用，并且很少有人知道形态发生如何影响分化，尽管它们被认为是紧密相连的。我们将在未来5年内通过研究以下短期目标来解决这些问题：目标1。确定Ste 20激酶家族成员Misshapen（Msn）在调节MF进展中的作用和机制。最近，我们发现了一个新的作用，Ste 20激酶Msn作为一个负调节MF进展。msn的缺失导致细胞形态改变。Ste 20激酶有不同的作用，我们建议，MSN的公认的作用，作为一个调节整合素是中央的能力，调节MF。我们将通过免疫荧光、遗传相互作用研究和生化测定来确定Msn如何调节整合素的稳定性、定位和活性。此外，我们将调查的微管，肌球蛋白和肌动蛋白的Msn的调节，使用类似的多方面的approaches.Objective2：表征细胞-细胞外基质（ECM）粘附相关成分的表达，定位和功能在幼虫的眼睛发育。迄今为止，我们对眼部MF进展的理解主要限于顶端细胞表面和细胞-细胞粘附。我们的目的是确定在基底细胞表面的细胞骨架球员的作用和细胞-ECM粘附在这个动态过程中的相对贡献。鉴于在其他形态发生背景下确定的粘附和细胞骨架重塑的关键作用，我们假设一个类似的，但尚未认识到的MF进展的贡献。我们将对眼形态发生过程中细胞外基质和细胞骨架成分的表达和定位进行深入分析。我们将使用遗传分析来确定整合素亚基在招募ECM因子以及促进细胞分化中的相对功能要求。

The long-term goal of my research program is to understand how groups of cells develop into specialized adult organs. Such a process requires regulation of growth, morphogenesis and differentiation. My group has focused primarily on the fruit fly eye to investigate numerous aspects of cell signaling that drive tissue specification. We now turn our attention to the events that occur after cell signaling and regulation of gene expression has occurred. Specifically, we are interested in the mechanical and structural changes that lead to the formation of the final three-dimensional organ. The insights we gain are likely to be broadly applicable to understanding how an undifferentiated epithelium develops into a specialized adult organ.My lab uses the well-characterized, genetically-tractable fruit fly Drosophila as a model organism to understand how cellular events are regulated during eye formation. Adult tissues are patterned during larval stages in discrete sacs of epithelial cells called imaginal discs. The adult eye arises from the eye disc and comprises an ordered array of unit eyes. Eye development initiates at the posterior edge of the disc and moves anteriorly in a virtual "wave" of differentiation known as the morphogenetic furrow (MF). The MF is seen as a narrow band of cells constricting both apically and apico-basally which causes them to appear as a physical groove in the epithelium. Cells anterior to the MF exist in an undifferentiated proliferative state, while those behind the MF undergo morphogenesis and differentiation. Thus the MF represents the transition point between cell division and subsequent retinal differentiation. The pace of the MF is tightly regulated to ensure the proper balance between these two opposing cellular states. To date, few studies have addressed the role of the profound cellular shape changes that occur during MF progression, and little is known about how morphogenesis influences differentiation, although they have been proposed to be tightly linked. We will address these issues through researching the following short-term objectives over the next 5 years:Objective 1. Determine the role and mechanism of the Ste20 kinase family member Misshapen (Msn) in regulating MF progression. Recently we found a novel role for the Ste20 kinase Msn as a negative regulator of MF progression. Loss of msn leads to altered cell morphology. Ste20 kinases have diverse roles, and we propose that Msn’s putative role as a regulator of integrins is central to its ability to regulate the MF. We will determine how Msn regulates integrin stability, localization and activity through immunofluorescence, genetic interactions studies and biochemical assays. Further, we will investigate regulation of microtubules, myosin and actin by Msn, using similar multi-facetted approaches.Objective 2: Characterize the expression, localization and function of cell-extracellular matrix (ECM) adhesion associated components during larval eye development. To date, our understanding of MF progression in the eye has been largely restricted to apical cell surfaces and to cell-cell adhesion. We aim to determine the role of cytoskeletal players at the basal cell surface and the relative contribution of cell-ECM adhesion during this dynamic process. Given the critical roles identified for adhesion and cytoskeletal remodeling in other morphogenetic contexts, we hypothesize a similar but as yet unrecognized contribution to MF progression. We will perform an in depth analysis of the expression and localization of ECM and cytoskeletal components during eye morphogenesis. We will use genetic analyses to determine the relative functional requirements for integrin subunits in recruiting ECM factors, as well as in promoting cell differentiation.