RUI: The role of mitotic trafficking in cell fate specification

非技术段落：在胚胎发育过程中，细胞形成的组织类型主要由每个细胞从其邻居那里收到的信号决定。这些相同的信号也调节成人组织中功能齐全的细胞的行为。细胞信号的缺陷是许多先天缺陷的原因，也可能导致癌细胞的形成。尽管在理解细胞信号的分子基础方面取得了很大进展，但大多数工作都是在没有分裂的细胞中进行的。细胞分裂对细胞对信号反应的影响仍然知之甚少。这个项目将通过研究细胞分裂和信号之间的相互作用来帮助填补这一关键空白。这项拟议的实验将研究从相邻细胞接收信号的蛋白质如何在分裂细胞内四处移动。由于癌细胞和胚胎细胞都经常分裂，这些信号受体蛋白在细胞分裂过程中的分布很可能在创造胚胎细胞特性和促进癌细胞行为方面发挥关键作用。这项建议还将促进对不同的本科生研究人员进行集中培训，以设计和实施独立的研究项目。该项目还将通过与费城地区许多成熟的外展项目的互动来促进公共教育。技术段落：细胞命运诱导受到信号组件贩运的影响。最近的研究推翻了长期以来的假设，即膜运输在有丝分裂期间被关闭。因此，有丝分裂信号成分的运输可能在细胞命运决定中扮演着深刻的、在很大程度上未被认识的角色。PI的长期目标是了解细胞分裂如何影响感应信号处理。这个问题是通过检查心脏前体细胞在基础脊索中的诱导来解决的。PI利用Ciona胚胎的极端细胞简单性对诱导信号机制进行高分辨率的体内分析，并专注于依赖成纤维细胞生长因子(FGF)对心脏祖细胞谱系的诱导。成纤维细胞生长因子受体(FGFRs)的有丝分裂再分布可促进分化心脏祖细胞的诱导。PI假设有丝分裂蛋白调节富含FGFR的粘附域的运输，并将通过以下具体目标来检验这一假说：1)通过对活的完整胚胎中标记蛋白的图像分析来表征富含FGFR的信号域的有丝分裂运输；2)通过使用途径特异性标记物的共定位分析和有针对性地破坏途径特异性成分来描述特定的内吞途径在信号域重新分布中的作用；3)确定有丝分裂酶如何通过靶向干扰激酶活性来影响富含FGFR的信号域的胞内转运。拟议研究的完成将为胚胎和干细胞中分裂和信号之间的相互作用提供基本的见解。

Non-Technical Paragraph:In developing embryos, the type of tissue that a cell becomes is primarily determined by signals each cell receives from its neighbors. These same signals also regulate the behavior of fully functional cells in adult tissues. Defects in cell signaling are the cause of many birth defects and can also cause cancer cells to form. Although great strides have been made in understanding the molecular basis of cell signaling, most of this work has been conducted in cells that are not dividing. The effect of cell division on cell response to signals remains poorly understood. This project will help fill this crucial gap by examining the interplay between cell division and signaling. The proposed experiments will examine how proteins that receive signals from neighboring cells are moved around inside dividing cells. Because both cancer cells and embryonic cells frequently divide, the distribution of these signal-receiver proteins during cell division is likely to play a crucial role in creating embryonic cell identity and in promoting cancerous cell behaviors. This proposal will also promote intensive training of diverse undergraduate researchers in designing and carrying out independent research projects. The project will also promote public education through interactions with many well-established outreach programs in the Philadelphia area.Technical Paragraph:Cell fate induction is affected by trafficking of signal components. Recent studies have overturned the long-held assumption that membrane trafficking is shut down during mitosis. Thus, mitotic trafficking of signaling components may play a profound, largely unrecognized role in cell fate specification. The long-term goal of the PI is to understand how cell division affects inductive signal processing. This question is addressed by examining heart progenitor induction in the basal chordate, Ciona intestinalis. The PI has exploited the extreme cellular simplicity of Ciona embryos to perform high-resolution, in vivo analysis of inductive signaling mechanisms, and focuses on Fibroblast Growth Factor (FGF)-dependent induction of the heart progenitor lineage. Mitotic redistribution of FGF receptors (FGFRs) was found to promote differential heart progenitor induction. The PI hypothesizes that mitotic kinases regulate trafficking of FGFR-enriched adherent domains, and will test this hypothesis through the following specific aims: 1) Characterization of mitotic trafficking of FGFR-enriched signaling domains through image analysis of tagged proteins in live, intact embryos; 2) Delineation of the role of specific endocytic pathways in signaling domain redistribution through co-localization analysis using pathway-specific markers and targeted disruption of pathway-specific components; 3) Determination of how mitotic kinases affect endocytic trafficking of FGFR-enriched domains through targeted disruption of kinase activity. Completion of the proposed studies will provide fundamental insights regarding the interplay between division and signaling in both embryonic and stem cells.