Molecular Regulation of Choanoflagellate-Bacteria Signaling Interactions

描述（由申请人提供）：动物在充满微生物的世界中生活和进化;因此，动物-细菌协会，从致病到互利共生，是古老而普遍的。了解真核生物的细菌信号转导机制和进化的进展受到缺乏实验上易处理和遗传学相关研究模型的限制。我们的实验室已经发现，在choanoflagellate Salpingoeca rosetta中多细胞菌落的发育受到来自细菌Algoriphagus sp.的化学信号的调节。阐明这种信号相互作用的分子机制有望为细菌共生体和动物之间的发育信号提供重要的见解，因为（1）choanoflagellates是动物最近的活体亲戚，（2）Bacteroidetes细菌，其中嗜Algoriphagus是一个成员，占主导地位的微生物的动物肠道，在那里他们施加影响的发展，健康和疾病。 我们提出了三个目标，以确定潜在的分子信号的机制Algoriphagus细菌和其调节choanoflagellate菌落发育。首先，与克拉迪实验室（哈佛医学院）合作，我们将从不同的细菌中分离出菌落诱导化合物，确定它们的结构，并结合使用有机化学和生物合成基因的经典遗传操作来进行结构/功能分析。其次，我们将通过标记细菌诱导物和可视化信号传递的动力学来定义细菌和领鞭毛虫之间的信号传导界面。第三，我们将确定choanoflagellate受体（S）的细菌信号分子使用生物化学和候选基因的方法。 这项研究有可能揭示王国间信号传导的实际机制，这将使我们能够研究现代宿主-细菌相互作用的进化。

DESCRIPTION (provided by applicant): Animals live and evolved in a world teeming with microbes; as a result, animal- bacterial associations, ranging from pathogenic to mutualistic, are ancient and ubiquitous. Progress toward understanding mechanisms and evolution of bacterial signaling with eukaryotes has been limited by the paucity of experimentally tractable and phylogenetically relevant research models. Our lab has discovered that the development of multicelled colonies in the choanoflagellate Salpingoeca rosetta is regulated by a chemical signal from the bacterium Algoriphagus sp. Elucidating the molecular mechanisms underlying this signaling interaction promises to provide important insights into developmental signaling between bacterial symbionts and animals because (1) choanoflagellates are the closest living relatives of animals and (2) Bacteroidetes bacteria, of which Algoriphagus is a member, predominate the microbiomes of animal intestines, where they exert influences on development, health, and disease. We propose three aims to determine the mechanisms underlying molecular signaling by Algoriphagus bacteria and its regulation of choanoflagellate colony development. First, in collaboration with the Clardy lab (Harvard Medical School) we will isolate colony-inducing compounds from diverse bacteria, determine their structures and use a combination of organic chemistry and classical genetic manipulations of biosynthetic genes to perform structure/function analyses. Second, we will define the signaling interface between bacteria and choanoflagellates by tagging the bacterial inducer and visualizing dynamics of signal delivery. Third, we will identify the choanoflagellate receptor(s) for bacterial signaling molecules using biochemical and candidate gene approaches. This research has the potential to uncover the actual mechanisms involved in inter-kingdom signaling which will allow us to examine the evolution of modern host- bacterial interactions.