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剂如何导致 具有显著组织特异性的综合征。我们正在开发新的实验模型， 果蝇强大的遗传工具来解决这个问题。我们将测试是否组织特异性 遗传和化学应激源的发生是因为它们靶向一般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的 无菌，其他方面正常。我们假设这种高度特异性的表型是由于 该等位基因与其它呼吸链蛋白之一的睾丸特异性同种型结合起作用。 事实上，睾丸中细胞色素c的体细胞形式的异位表达抑制了不育性。 表型。拟议中的实验将严格测试这种不育是否是由于特定的缺陷， 突变型细胞色素氧化酶和睾丸特异性细胞色素c亚型的伙伴关系。此外，本发明还 我们将设计蝇眼作为生物传感器，用于破坏线粒体的同种型特异性相互作用， 功能，并将其应用于识别干扰这些相互作用的突变和化学物质。 我们还将探讨由两种缺陷的协同作用产生的组织特异性，其中组织特异性缺陷 使组织对不同的遗传和化学应激物敏感。E2 F的眼特异性敲低受损 生长以产生略微缩小的眼睛。它还使眼睛对线粒体应激敏感。低剂量的 在其他组织中没有显著作用的寡霉素与眼睛中的E2 F：RNAi协同作用， 变形（例如触角长出眼睛）和肥大。我们假设这 发育不全/肥大依赖于具有生物学普遍关系的两种输入。任何能抑制 特定组织的生长创造了有利于细胞的选择性环境， 通过转化为另一种细胞类型（transdetermination）。第二种压力破坏了发展的命运 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。 我们将测试这个模型，并筛选自然突变和环境化学物质， 协同投入。由于哺乳动物表达许多蛋白质作为组织特异性同种型，它们携带许多蛋白质， 这些基因可以通过突变来产生一种选择来进行转决定。如果没有协同输入，这些突变 影响很小，而且可以累积。因此，我们怀疑人类有大量的， 潜在的“多态性”池，产生了多种化学敏感性。对致敏性的认识 基因突变应该使DNA测序能够应用于个性化的医疗保健。

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.