Immunity to a Parasitoid Wasp in Drosophila melanogaster

描述（由申请人提供）：果蝇已经成为先天免疫研究的重要模型系统，特别是对细菌和真菌感染的体液（无细胞）反应。果蝇也会受到拟寄生蜂的攻击，寄生蜂会在果蝇幼虫中产卵。蝇幼虫产生一种免疫反应，其中血淋巴细胞附着并包裹黄蜂卵，在卵周围沉积一层黑色素，并在黑色素化的胶囊内释放细胞毒性分子来杀死卵。这种反应的分子基础，以及一般的细胞免疫反应，人们知之甚少。先天免疫系统如何将宿主组织与密切相关的寄生虫组织区分开来，也尚不清楚。我将使用遗传作图、mRNA基因表达和其他方法来确定D. melanogaster对一种拟寄生蜂的抗性和抗性变异的遗传基础。此外，我将测量进化上保守的酚氧化酶途径（负责黑色素的产生）的DNA序列变化和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.