Role of Viruses in the Life Cycle and Endosymbiosis of a Sea Slug

海蛞蝓（Elysia chlorotica）的消化细胞与藻类（Vaucheria litorea）的叶绿体具有内共生关系。这些从摄入的沃切菌中获得的叶绿体在海蛞蝓体内保持活力和功能长达数月。pi先前已经证明，捕获的功能性质体可以合成蛋白质，包括那些似乎在鼻涕虫基因组中编码的蛋白质。他们最近确定了其中一些蛋白质属于光收集复合体I (LHCI)，并初步发现了LCHI基因存在于蛞蝓基因组DNA中的分子证据。为了这个概念验证奖，pi将进行旨在识别宿主细胞基因组中的质体蛋白基因的实验。这种从共生体到宿主细胞核的基因转移肯定与广泛接受的胞内细胞器（如线粒体和叶绿体）的内共生起源机制有关。如果能够在绿藻中证明由内源性病毒介导的藻类和蛞蝓之间成功的种间基因转移，那么将为这一过程提供一个示范机制。

The digestive cells of the sea slug, Elysia chlorotica, have an endosymbiotic association with chloroplasts from the alga, Vaucheria litorea. These chloroplasts, obtained from ingested Vaucheria, remain viable and functioning within the sea slug for months. The PIs have previously demonstrated that the captive, functional plastids synthesize proteins, including those that seem to be coded for in the slug genome. They have recently identified some of those proteins as belonging to the light harvesting complex I (LHCI) and have developed preliminary molecular evidence for the presence of the LCHI gene in the slug genomic DNA. For this proof-of-concept award, the PIs will conduct experiments designed to identify plastid protein genes in the host cell genome. Such transfers of genes from the symbiont into the host cell nucleus must certainly have been associated with the mechanism of the widely accepted endosymbiotic origin of intracellular organelles, such as mitochondria and chloroplasts. If a successful interspecies gene transfer between an alga and a slug mediated by an endogenous virus can be demonstrated in the case of E. chlorotica, then an exemplary mechanism for this process will have been provided.