PATTERNING AND MORPHOGENESIS OF KUPFFER'S VESICLE

脊椎动物体内的器官通常是由大量的细胞形成的，这些细胞来源于多种细胞， 胚胎组织，具有多种生理和结构功能。这种复杂性使得 很难解开控制器官发生的分子机制的网络。与此相反， Kupffer囊泡（KV）是一种高度组织化的胚胎结构，由大约四个 十几个细胞。这些细胞来源于在原肠胚形成过程中迁移的背侧先行细胞（DFC 然后进入尾芽形成KV。虽然KV是在1868年描述的， KV在硬骨鱼中是保守的，直到我们的研究才知道KV的功能。我们发现KV上皮层 具有活动纤毛，其投射到KV腔中并产生左右不对称的流体流动。利用变种人， 通过吗啡注射和激光消融，我们发现了DFC和KV的功能： LR在大脑、心脏和肠道原基中的模式。我们已经证明了两个T-box转录因子 基因，无尾（ntl）和spadelite（spt），在KV纤毛基因表达，器官发生， 模式和功能。其中一些角色是不同的，有些是重叠的，这表明， 是由NTL、SPT或NTL、SPT和其它之间的组合相互作用控制的基因的多个群组 途径。我们的初步结果表明，转录因子基因rfx 2和hfh 4与 这些T-box依赖的途径;这些基因的变形不改变KV的形成，但改变了 cilia纤毛to function功能properly正常.该项目的目标是阐明复杂的监管相互作用，基于 四个转录因子基因ntl，spt，rfx 2和hfh 4，它们协调纤毛的形成，纤毛的发育和功能， 这个简单但必不可少的胚胎器官。

Organs in the vertebrate body are usually formed by large numbers of cells that are derived from multiple embryonic tissues and that have diverse physiological and structural functions. This complexity makes it difficult to unravel the networks that control the molecular mechanisms of organogenesis. In contrast, Kupffer's Vesicle (KV) is a'^highly organized embryonic structurethat is comprised of approximately four dozen cells. These cells are derived from Dorsal Forerunner Cells (DFCs) that migrate during gastrulation and then ingress into the tailbud to form the KV. Although the KV was described in 1868 and is highly conserved in teleosts, until our studies the function of KV was unknown. We found that KV epithelial lining has motile cilia that project into the lumen of KV and generate right-left asymmetric fluid flow. Using mutants, morpholino injections and laser ablations, we have discovered the function of the DFCs and KV: regulation of LR patterning in the brain, heart and gut primordia. We have shown that two T-box transcription factor genes, no tail (ntl) and spadetail (spt), have multiple roles in KV cilia gene expression, organogenesis, patterning and function. Some of these roles are distinct, and some are overlapping, suggesting that there are multiple cohorts of genes controlled by ntl, spt or combinatorial interactions between ntl, spt and other pathways. Our preliminary results indicate that the transcription factor genes rfx2 and hfh4 intersect with these T-box-dependent pathways; morphants of these genes do not alter KV formation, but alter the ability of cilia to function properly. The goal of this project is to elucidate the complex regulatory interactions, based on four transcription factor genes, ntl, spt, rfx2 and hfh4, that coordinate the formation, ciliagenesis and function of this simple but essential embryonic organ.