Identifying the mechanistic role of the Wunens during germ cell migration

描述(申请人提供)：细胞迁移描述细胞定向移动到体内的特定位置。这一过程是组织形成和多细胞生物体发展的关键步骤。此外，细胞迁移是维持人体免疫系统和伤口愈合所必需的。细胞迁移中断可能会导致血管疾病和癌症进展等医疗问题。果蝇的生殖细胞经历了一个刻板的和受基因调控的迁移过程，因此为研究细胞迁移提供了一个理想的模型系统。遗传学研究发现，果蝇胚胎中一个保守的脂质磷酸酶(LPP)家族Wunen是生殖细胞迁移的重要调节因子。Wunens的功能是作为生殖细胞排斥剂，并需要引导生殖细胞沿着正确的路线到达胚胎性腺。在中肠和中枢神经系统等体细胞缺乏Wunen功能的情况下，生殖细胞迁移异常，生殖细胞散布在胚胎各处。此外，生殖细胞内的武能功能是生存和正常迁移所必需的。与其他LPP类似，Wunen被认为是通过细胞外磷脂底物去磷酸化发挥作用的。然而，Wunens调节生殖细胞迁移的机制尚不清楚。这项提案的目标是确定和描述这些机制的特点。我们推测，Wunens可以分解和摄取一种分泌的磷脂，这种磷脂是生殖细胞迁移和存活所需的化学诱导剂和膜动力学的调节器。体细胞中局部的Wunen活动产生磷脂梯度，引导生殖细胞适当地迁移到发育中的性腺。为了解决这个模型，生殖细胞将首先通过细胞分离技术从胚胎中分离出来，使我们能够在简化的环境中研究它们。分离的生殖细胞将用于体外迁移试验，使我们能够概括Wunen的趋化活性，并鉴定Wunen调节的具有趋化活性的磷脂。Wunen在生殖细胞膜动力学中的作用将通过对缺乏Wunen功能的分选细胞进行详细的表型分析来确定。最后，乌嫩介导的脂质摄取的机制将通过基于细胞的筛选这一过程的其他介体来阐明。进一步的研究将集中在那些被预测在膜动力学调节中发挥作用的基因。综上所述，这些数据将为脂质调节促进必要的细胞迁移过程的机制提供洞察力。

DESCRIPTION (provided by applicant): Cell migration describes the directed movement of cells to a particular location in the body. This process is an essential step in tissue formation and the development of multicellular organisms. Furthermore, cell migration is required for maintenance of the body's immune system and wound healing. Disruptions in cell migration can lead to medical problems such as vascular disease and the progression of cancer. The germ cells of the fruit fly, Drosophila melanogastor, undergo a stereotypic and genetically regulated migration process and thus provide an ideal model system to study cell migration. Genetic studies have identified a conserved family of lipid phosphate phosphatases (LPPs), the Wunens, as important regulators of germ cell migration in the Drosophila embryo. The Wunens function as germ cell repellents and are required for directing germ cells along a proper route to the embryonic gonad. In the absence of Wunen function in somatic cells such as the midgut and central nervous system, germ cell migration is abnormal with germ cells found scattered throughout the embryo. Furthermore, Wunen function is required within the germ cells for survival and proper migration. Similar to other LPPs, the Wunens are thought to function by dephosphorylation of extracellular phospholipid substrates. However, the mechanisms by which Wunens regulate germ cell migration are not well understood. The goal of this proposal is to identify and characterize these mechanisms. We hypothesize that Wunens hydrolyze and uptake a secreted phospholipid which acts as a chemoattractant and regulator of membrane dynamics required for germ cell migration and survival. Localized Wunen activity in somatic cells creates a phospholipid gradient, directing the proper migration of germ cells to the developing gonad. To address this model, germ cells will first be isolated from the embryo by cell sorting techniques, allowing us to study them in a simplified environment. Sorted germ cells will utilized in an ex vivo migration assay, allowing us to recapitulate Wunen chemorepellent activity and identify Wunen-regulated phospholipids with chemoattractant activity. The role of Wunen in germ cell membrane dynamics will be determined by a detailed phenotypic analysis of sorted cells lacking Wunen function. Finally, the mechanism of Wunen-mediated lipid uptake will be clarified by a cell-based screen for additional mediators of this process. Further studies will be focused on those genes predicted to have roles in the regulation of membrane dynamics. Taken together, these data will provide insight to the mechanisms by which lipid regulation promotes an essential cell migration process.