Immunity to a Parasitoid Wasp in Drosophila melanogaster

描述(申请人提供)：果蝇已成为研究先天性免疫，特别是对细菌和真菌感染的体液(无细胞)反应的重要模型系统。果蝇也会受到寄生蜂的攻击，这些寄生蜂在苍蝇幼虫身上产卵。苍蝇幼虫进行免疫反应，血淋巴(血液)细胞附着并包裹在黄蜂卵上，在黄蜂卵周围沉积一层黑色素，并在黑化的被膜内释放细胞毒性分子以杀死黄蜂卵。这种反应的分子基础，以及一般的细胞免疫反应，目前还知之甚少。也不知道先天免疫系统如何区分宿主组织和密切相关的寄生虫组织。我将使用遗传作图、信使核糖核酸基因表达和其他方法来确定对黑腹小蜂寄生蜂的抗性的遗传基础和抗性的变异。此外，我将测量DNA序列的变异和进化上保守的酚氧化酶途径已知基因的转录水平对果蝇黑色素沉积效率的影响。

DESCRIPTION (provided by applicant): Drosophila has become an important model system for the study of innate immunity, in particular the humoral (cell-free) response to bacterial and fungal infections. Drosophila is also attacked by parasitoid wasps, which lay their eggs in fly larvae. Fly larvae mount an immune response in which hemolymph (blood) cells attach to and encapsulate the wasp egg, deposit a layer of melanin around the egg, and release cytotoxic molecules within the melanized capsule to kill the egg. The molecular basis for this response, and for the cellular immune response in general, is poorly understood. Nor is it understood how the innate immune system distinguishes host tissue from that of closely related parasites. I will use genetic mapping, mRNA gene expression, and other methods to determine the genetic basis for resistance, and variation in resistance, against a parasitoid wasp in D. melanogaster. Furthermore, I will measure the effect of variation in DNA sequence and transcription levels of known genes of the evolutionarily conserved phenoloxidase pathway, responsible for the generation of melanin, on the efficiency of melanin deposition in Drosophila.