Cellular and Genetic Analysis of Lysosome and Lysosome-Related Organelle Biogenesis in C. Elegans

溶酶体是一种几乎存在于所有动物细胞中的膜结合室，在细胞内外衍生物质的降解中具有很好的特性。虽然关于溶酶体在细胞中执行的不同和重要的过程已经了解了很多，但在复杂的多细胞动物中溶酶体组装的潜在机制，特别是在胚胎发生期间的发育，相对来说还没有被研究过。为了帮助理解这些过程，赫尔曼博士正在识别和表征在模式多细胞生物体秀丽线虫的胚胎肠道中组装溶酶体所需的基因。赫尔曼实验室已经确定肠道颗粒是一种特定的细胞类型，与溶酶体相关的细胞器，具有储存脂肪的功能。为了详细了解控制肠道颗粒形成的机制，赫尔曼实验室分离了一组在肠道颗粒生物发生中存在缺陷的glo突变体，并对其进行了鉴定。到目前为止，大多数在溶酶体相关细胞器的生物发生中起作用的基因并不是胚胎存活所必需的。赫尔曼实验室已经确定了22个胚胎致命的Glo突变体，这些突变体在细胞外错位肠道颗粒内容物。这些菌株中活性被破坏的肠道颗粒形成所需的基因将被分子鉴定。对这些基因的研究可能会为多细胞生物体中溶酶体生物发生所必需的途径提供新的见解。最近对线虫的研究表明，肠道原基中含有LMP-1：：GFP的卵黄血小板和LMP-1：：GFP也代表溶酶体相关的细胞器。含有细胞器、卵黄小板和肠道颗粒的LMP-1：：GFP是否具有传统溶酶体、其他内体隔室的特征，或者彼此之间的特征，将用显微镜和遗传学的方法进行研究。如果这三个隔室代表不同的溶酶体相关细胞器，胚胎肠道将提供一个强大的遗传系统，以研究如何在同一细胞中形成结构和功能不同的溶酶体隔室。该项目每年将有25到30名本科生参与独立的、动手的、原创的研究。在PI实验室和高级细胞生物学课程(招生24人)工作的本科生将进行这些研究。这项工作将提供对溶酶体组装的分子洞察力，这些溶酶体组装可能在所有多细胞动物的溶酶体组装/维持中保守。

Lysosomes are membrane bound compartments found in nearly all animal cells that have well characterized roles in the degradation of intra and extra-cellular derived material. While much has been learned regarding the diverse and important processes that lysosomes carry out in cells, the mechanisms underlying the assembly of lysosomes in complex multicellular animals, especially as they develop during embryogenesis, are relatively unstudied. To aid in understanding of these processes, Dr. Hermann is identifying and characterizing genes necessary for the assembly of lysosomes in the embryonic intestine of the model multicellular organism C. elegans. The Hermann lab has identified gut granules as a cell type specific, lysosome-related organelle that functions in the storage of fat. To gain detailed insight into the mechanisms controlling the formation of gut granules the Hermann lab has isolated and is characterizing a collection of glo mutants that are defective in gut granule biogenesis. Most genes identified to date that function in the biogenesis of lysosome-related organelles are not required for embryonic viability. The Hermann lab has identified 22 embryonic lethal glo mutants that extracellularly mislocalize gut granule contents. The genes necessary for the formation of gut granules whose activity is disrupted in these strains will be molecularly identified. Studies of these genes are likely to provide novel insights into the pathways necessary for lysosome biogenesis in multicellular organisms. Recent studies in C. elegans suggest that yolk platelets and LMP-1::GFP containing compartments in the intestinal primordium also represent lysosome-related organelles. Whether LMP-1::GFP containing organelles, yolk platelets, and gut granules have characteristics of conventional lysosomes, other endosomal compartments, or each other will be investigated using microscopic and genetic approaches. If these three compartments represent distinct lysosome-related organelles, the embryonic intestine would provide a powerful genetic system to investigate how structurally and functionally distinct lysosomal compartments are formed in the same cell.The project will involve 25 to 30 undergraduates a year in independent, hands-on, original research. Undergraduate students working in the PI's lab and upper division Cell Biology course (enrollment 24) will carry out the studies. The work will provide molecular insights into the assembly of lysosomes likely to be conserved in the assembly/maintenance of lysosomes in all multicellular animals.