Transcriptional control of collective cell migration

项目摘要/摘要 关键的生理和病理过程，如伤口愈合、新生血管生成和 癌症转移依赖于定向的集体细胞迁移，由此细胞群变得两极化和 以有序的方式一起行动。细胞组集体迁移的能力部分取决于 特定于组织的转录输入，它定义了它们所表达的基因的补充，从而决定了它们的 移民的能力。这个项目的长期目标是了解组织特异性转录是如何 调节剂控制着基本的细胞过程，这些过程是细胞定向集体迁移的基础。为了实现这一目标， 脊索动物的简化胚胎将被用来研究海鞘动物的迁徙。 心前中胚层细胞，称为“干腹侧细胞”(TVCs)。TVC提供了最简单的可能模式 活体胚胎中定向的集体细胞迁移。在胚胎的两侧，只有两个细胞一起迁移 并显示与迁移方向一致的清晰的引导者-拖车(L-T)极性：引导者TVC显示 宽阔的前缘和比拖车更显眼的突出部分。此前已经确定， MESP、成纤维细胞生长因子信号转导和FoxF转录输入决定血管内皮细胞的能力 迁徙。拟议研究的具体目标是了解转录输入如何有助于 领导者TVC的规格，并影响其突出的活动。在初步研究的基础上 观察到，假设(1)腹侧来源的骨形态发生蛋白(BMP)有助于 L-T使下游靶基因的表达两极化，包括Lef/Tcf转录因子； 这些转录输入决定了Rho GTP酶RhoDF和CDC42的L-T极化活性， 将对形成膜突起所需的物质进行测试。为了解决这些可能性， 为了了解L-T，我们将首先分析Lef/Tcf在TVCs中的表达、顺式调控及其功能 两极化转录输入。第二，将使用定量成像方法记录L-T 野生型条件下和处理后RhoDF、CdC42的极化和突出活动 转录调节因子和其他候选Rho GTP酶对L-T的影响 极化的膜突起。最后，候选调节的集体细胞极化效应因子和 将使用TVC特定的全基因组微阵列分析来鉴定突起活性，然后 通过原位杂交和靶向过表达进行系统表达和功能分析， 分别进行了分析。我们的期望是确定集体细胞迁移的转录控制机制。 通过研究转录调控因子、调控效应因子及其对Rho GTP酶的影响 作为集体细胞极化和膜形成基础的信号和肌动蛋白细丝动力学 突出物。

PROJECT SUMMARY / ABSTRACT Critical physiological and pathological processes, such as wound healing, de novo vessel angiogenesis and cancer metastasis, rely on directed collective cell migrations, whereby groups of cells become polarized and moves together in an orderly fashion. The ability of cell groups to migrate collectively is determined in part by the tissue-specific transcriptional inputs that define the complement of genes that they express and thus their competence to migrate. The long-term goal of this project is to understand how tissue-specific transcription regulators control the basic cellular processes underlying directed collective cell migration. To this aim, the simplified embryos of a chordate species, the ascidian Ciona intestinalis, will be used to study the migration of pre-cardiac mesoderm cells, called "trunk ventral cells" (TVCs). The TVCs provide the simplest possible model of directed collective cell migration in live embryos. On each side of the embryo, only two cells migrate together and display a clear Leader-Trailer (L-T) polarity aligned with the direction of migration: the leader TVC displays a broad leading edge and more conspicuous protrusions than the trailer. It was previously established that Mesp, Fibroblast Growth Factor (FGF) signaling and FoxF transcriptional inputs determine the ability of TVCs to migrate. The specific goal of the proposed research is to understand how transcriptional inputs contribute to the specification of the leader TVC and influence its protrusive activity. On the basis of preliminary observations, the hypotheses that (1) a ventral source of bone morphogenetic proteins (BMP) contributes to the L-T polarized expression of downstream target genes, including the Lef/Tcf transcription factor; and (2) these transcriptional inputs determine the L-T polarized activities of the Rho GTPases RhoDF and Cdc42, which are required for the formation of membrane protrusions will be tested. To address these possibilities, the expression, cis-regulation and function of Lef/Tcf in the TVCs will first be analyzed in order to understand L-T polarized transcriptional inputs. Second, quantitative imaging methods will be used to document the L-T polarization of RhoDF, Cdc42 and protrusive activities in wild-type conditions and after manipulations of transcription regulators and other candidate Rho GTPases in an attempt to characterize their effects on L-T polarized membrane protrusions. Finally, candidate regulated effectors of collective cell polarization and protrusive activity will be identified using TVC-specific whole genome microarray analysis followed by systematic expression and functional analyses by in situ hybridization and targeted over-expression, respectively. The expectation is to determine a mechanism of transcriptional control for collective cell migration by characterizing the transcription regulators, the regulated effectors and their effects on the Rho GTPase signaling and actin filament dynamics that underlie collective cell polarization and the formation of membrane protrusions.