Dissertation Research: Functional Divergence of Cytochrome C Paralogs

线粒体电子传递链中的蛋白质由必须紧密相互作用的核和线粒体编码的亚基组成。在果蝇中，超过五分之一的核编码亚基有第二个拷贝，只在睾丸中表达。本研究旨在分析其中一个重复基因细胞色素-c近端和远端的功能差异。建议用来测试这一点的实验如下。1)测量在胞体和睾丸中同时表达睾丸或体细胞色素c的转基因果蝇的适合性。对于躯体功能，将测量寿命、繁殖力和幼虫存活率等特征。对于睾丸功能，将测量精子存活率、精子数量和精子竞争能力等指标。2)通过量化组织特异性细胞色素c氧化酶在氧化睾丸或体细胞色素c时的酶活性来测试组织特异性酶复合体的共适应。这项研究综合了1)生殖进化，通过测量以前未被研究的一类生殖蛋白的生殖适合性，2)通过测试强迫非共适应分子相互作用而导致的功能中断，2)通过测试迫使非共适应分子相互作用而导致的功能中断，以及3)通过测量两个基因拷贝的功能差异，整合了基因复制和亚功能化的进化。因此，这些发现将为广泛的研究人员提供信息，并将在其他松散关联的领域之间提供紧密的联系。

Proteins in the mitochondrial electron transport chain are composed of both nuclear and mitochondrially encoded subunits that must tightly interact. In Drosophila, over one fifth of the nuclear encoded subunits have a second copy that is only expressed in the testes. This study aims to dissect the functional differences of one such duplicate gene, cytochrome-c proximal and cytochrome-c distal. The experiments proposed to test this are as follows. 1) Measure fitness correlates of transgenic flies expressing either testis or somatic cytochrome c in both the soma and testes. For somatic function the traits of lifespan, fecundity, and larval viability will be measured. For testis function the traits of sperm viability, sperm count and sperm competitive ability will be measured. 2) Test for coadaptation of tissue specific enzyme complexes by quantifying enzymatic activity of tissue specific cytochrome c oxidase when oxidizing either testis or somatic cytochrome c.This study integrates 1) reproductive evolution, by measuring reproductive fitness traits in a previously uninvestigated class of reproductive proteins, 2) evolution of coadaptation, by testing the functional disruption induced by forcing non-coadapted molecules to interact and 3) evolution of gene duplication and subfunctionalization, by measuring functional divergence of two gene copies. As such, findings will prove informative to a broad range of researchers and will provide tight connections between otherwise loosely affiliated fields.