The genetic basis for tissue specific sensitivities to mitochondrial stress

摘要 我们的目标是了解破坏一般线粒体功能的突变和抑制物是如何导致 具有明显组织特异性的综合征。我们正在开发新的实验模型，在这些模型中我们可以 果蝇中强大的遗传工具来解决这个问题。我们将测试是否具有组织特异性 遗传和化学应激源的发生是因为它们针对的是普通线粒体之间的相互作用 功能和组织特异性基因。果蝇细胞色素氧化酶亚基1的一个特殊突变体是雄性 无菌，其他方面正常。我们假设这种高度特异的表型是由于 这种等位基因与其他呼吸链蛋白之一的睾丸特定亚型一起工作。 事实上，在睾丸中异位表达体细胞色素c可以抑制不育症。 表型。拟议中的实验将严格测试这种不孕不育是否是由于大脑中的特定缺陷。 突变的细胞色素氧化酶与睾丸特异性细胞色素c亚型的配对。此外， 我们将设计苍蝇眼作为生物传感器来破坏线粒体的异构体特异性相互作用。 功能，并将应用它来识别干扰这些相互作用的突变和化学物质。 我们还将探索由两个缺陷协同产生的组织特异性，其中一个组织特异性缺陷 使组织对不同的遗传和化学应激源敏感。E2F的眼睛特异性击倒受到损害 生长所产生的眼睛略有缩小。它还使眼睛对线粒体压力敏感。低剂量的 在其他组织中没有明显作用的寡霉素，在眼睛中与E2F：RNAi协同作用产生组织 变形(例如，触角从眼睛里长出来)和肥大。我们假设这是 发育不全/肥大依赖于两个具有生物学普遍关系的输入。任何能抑制 特定组织的生长创造了一个选择性的环境，有利于细胞逃脱生长限制 通过转化为另一种细胞类型(转定)。第二个破坏发展命运稳定的压力 会为这次选择提供素材。线粒体压力似乎提供了这种不稳定的输入。 我们将测试这一模型，并筛选自然突变和环境化学物质 协同投入物。由于哺乳动物以组织特异性异构体的形式表达大量蛋白质，因此它们携带许多 基因可以发生突变，从而产生转化决定的选择。如果没有协同输入，这些突变 不会有什么影响，可能会累积起来。因此，我们怀疑人类人口中有大量的 潜伏的“多态”池，造成化学敏感性的多样性。对敏化的认识 突变应该会使DNA测序在个性化医疗保健中得到应用。

ABSTRACT Our goal is to understand how mutations and inhibitors that disrupt general mitochondrial functions can cause syndromes with marked tissue specificity. We are developing new experimental models in which we can bring the powerful genetic tools in Drosophila to bear on this question. We will test whether the tissue specificity of genetic and chemical stressors occurs because they target interactions between general mitochondrial functions and tissue specific genes. A particular mutant of Drosophila Cytochrome oxidase subunit 1 is male sterile, and otherwise normal. We hypothesize that this highly specific phenotype is the result of a failure of this allele to work conjunction with a testis specific isoform of one of the other respiratory chain proteins. Indeed, ectopic expression of the somatic version of Cytochrome c in the testis suppresses the sterility phenotype. The proposed experiments will rigorously test whether this sterility is due to a specific deficit in the partnership of the mutant Cytochrome oxidase and the testis specific isoform of Cytochrome c. Additionally, we will engineer the fly eye as a biosensor for disruption of isoform-specific interactions of mitochondrial functions, and will apply it to identify mutations and chemicals interfering with these interactions. We will also explore tissue specificity resulting from a synergy of two defects, where a tissue specific defect sensitizes a tissue to diverse genetic and chemical stressors. Eye specific knockdown of E2F compromised growth to produce a slightly reduced eye. It also sensitized the eye to mitochondrial stress. A low dose of oligomycin that is without notable effect in other tissues, synergizes with E2F:RNAi in the eye to produce tissue transformations (e.g. antennae growing out of the eye) and hypertrophy. We hypothesize that this dysgenesis/hypertrophy relies on two inputs with a biologically universal relationship. Any mutation that inhibits growth of a specific tissue creates a selective environment favoring cells that can escape the growth limitation by transforming to another cell type (transdetermination). A second stress that destabilizes developmental fate would produce the fodder for this selection. Mitochondrial stress appears to provide this destabilizing input. We will test this model and screen for natural mutations and environmental chemicals contributing to the synergizing inputs. Since mammals express numerous proteins as tissue-specific isoforms, they carry many genes that can mutate to create a selection for transdetermination. Without synergizing input, these mutations would have little impact and could accumulate. Thus, we suspect that the human population has a large and insidious pool of "polymorphisms" that creates a diversity of chemical sensitivities. Recognition of sensitizing mutations should empower application of DNA sequencing to personalized health-care.