Molecular genetic analysis of reproductive system development in nematodes C. elegans and C. briggsae

后生动物组织和器官的形成涉及许多基因表达的动态变化。这些基因是如何调控的，以及它们的表达变化对生物体有什么影响，目前还不清楚。秀丽隐杆线虫（Caenorhabditis elegans）及其近亲C. briggsae为研究发育过程中的基因调控和功能提供了许多优势。这两种模式生物具有许多方便的特征，并为探索所有真核生物中发生的生物现象提供了强大的分子和遗传工具。*秀丽隐杆线虫和秀丽隐杆线虫虽然表面上形态相似，但在编码区和非编码区均存在显著差异。这提供了一个独特的机会来研究基因和途径随时间的变化而没有明显的结构变化。这个过程被称为发育系统漂移（DSD），是遗传机制的进化变化，是关键和不变表型的基础。*为了研究器官形成和DSD的机制，我的实验室正在对这两种线虫的生殖系统发育，特别是外阴进行比较分析。外阴是雌性蠕虫（雌雄同体）的交配结构，通常由22个细胞组成。尽管它很简单，但该系统显示出功能的复杂性，在许多方面可以与人体器官相媲美。我们分离了大量具有异常表型的C. briggsae外阴突变体，包括Vul（无外阴，细胞少）、Muv（多外阴，细胞多）和Pvl（外阴突出，异常内翻）。秀丽隐杆线虫中相似的表型类别导致了对保守信号通路（例如Ras）和控制器官形成的转录网络的全面理解。我们发表的研究表明，秀丽隐杆线虫的一些外阴基因，如Cbr-lin-11/LIM-HOX和Cbr-pry-1/Axin的作用与秀丽隐杆线虫不同（见[1,2]）。最近我们发现muv类基因也显示出有趣的差异。在某些情况下，动物表现出在任何已知的秀丽隐杆线虫Muv突变体中都没有观察到的外阴诱导模式，这表明秀丽隐杆线虫的外阴发育是由不同的机制协调的。*为了对外阴发育进行比较研究，我们将运用经典遗传学、分子生物学、生物信息学等多种方法，并将其与包括snp芯片多态性定位和下一代测序在内的尖端技术相结合。我们的研究结果有望揭示动物形态和发育多样性基因网络的一些变化。这些发现将促进我们在发育和进化生物学领域的知识。*拟议的研究项目将培养在遗传学、细胞生物学、计算生物学、成像和转基因方面接受广泛培训的高素质人才。这些技能是支持加拿大生物医学科学所必需的，所获得的经验将使HQP适合学术界、工业界和政府工作。

Formation of tissues and organs in metazoans involve dynamic changes in the expression of many genes. How these genes are regulated and what impact changes in their expression have on the organism are not well understood. The nematode (worm) Caenorhabditis elegans and its close relative C. briggsae offer many advantages to study gene regulation and function during development. These two model organisms possess many convenient features and provide powerful molecular and genetic tools to explore biological phenomena that occur in all eukaryotes. * In spite of their superficially similar morphology, the genomes of C. elegans and C. briggsae show significant differences in both coding and non-coding regions. This provides a unique opportunity to investigate alterations in genes and pathways over time without obvious changes in structure. This process, termed developmental system drift (DSD), is the evolutionary change in genetic mechanisms that underlie crucial and invariant phenotypes. * To study the mechanisms of organ formation and DSD my laboratory is conducting a comparative analysis of reproductive system development, specifically the vulva, in these two nematodes. The vulva is a mating structure in female worms (hermaphrodites) that is normally composed of 22 cells. Notwithstanding its simplicity, the system exhibits functional complexities that are, in many ways, comparable to human organs. We have isolated a large number of C. briggsae vulva mutants with aberrant phenotypes including Vul (vulvaless, fewer cells), Muv (multivulva, more cells), and Pvl (protruding vulva, abnormal invagination). Similar phenotypic classes in C. elegans have led to a comprehensive understanding of conserved signaling pathways (e.g., Ras) and transcriptional networks that control organ formation. Our published work has shown that the roles of some of the C. briggsae vulva genes, such as Cbr-lin-11/LIM-HOX and Cbr-pry-1/Axin, have diverged from C. elegans (see [1, 2]). Recently we have found that Muv-class genes also show interesting differences. In some cases animals exhibit a vulval induction pattern that is not observed in any of the known C. elegans Muv mutants, demonstrating that vulval development in C. briggsae is orchestrated by diverged mechanisms. * To pursue comparative study of vulva development we will use a range of approaches in classical genetics, molecular biology, bioinformatics, and combine them with cutting-edge technologies including SNP-chip polymorphism mapping and next-generation sequencing. Our results promise to uncover some of the changes in gene networks that specify morphological and developmental diversity in animals. The findings will advance our knowledge in areas of developmental and evolutionary biology. * The proposed research projects will generate highly-qualified personnel (HQP) with a broad range of training in genetics, cell biology, computational biology, imaging and transgenics. These skills are needed to support Canadian biomedical science and the acquired experience will make HQP suitable in academia, industry and government jobs.