Functional respiratory chain analyses in murid xenomitochondrial cybrids expose coevolutionary constraints of cytochrome b and nuclear subunits of complex III
Functional respiratory chain analyses in murid xenomitochondrial cybrids expose coevolutionary constraints of cytochrome b and nuclear subunits of complex III
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DOI：
10.1093/molbev/msg132
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发表时间：
2003-07-01
影响因子：
10.7
通讯作者：
Trounce, IA
中科院分区：
文献类型：
--
作者：
McKenzie, M;Chiotis, M;Trounce, IA
大量现存的鼠科物种提供了研究核/线粒体呼吸链（RC）亚基相互作用的功能限制的机会，通过引入线粒体基因组从逐渐不同的物种到小家鼠mtDNA-less（rho（0））细胞。我们创建了一组这样的异种线粒体胞质杂交体，使用来自六种与M. M.估计在距今200万年至1200万年前，使用的种属为Mus spretus、Mus caroli、Mus dunni、Mus pahari、Otomys sporatits和Rattus norvegicus。部分线粒体DNA序列的简约性分析表明，与以前的分子遗传学的协议，除了Otomys没有巢内的鼠科建议最近的一些核基因分析。细胞产生的乳酸，一个敏感的指标，减少呼吸链ATP的生产，与分歧。使用酶学分析的嵌合RC复合物在分离的线粒体中的功能表征表明复合物I，III和IV，其具有在线粒体和核基因组中编码的亚基的活性的不同降低。复合物III显示出显着下降的电子传递功能，在最不同的xenocybrids，被大大减少在鼠xenocybridd和几乎没有在otomys xenocybridd。这表明与细胞色素B相互作用的核亚基在鼠RC亚基的协同进化中面临最大的限制。我们测序的细胞色素B基因的物种，用于确定潜在的氨基酸取代参与这种相互作用。复合物III对异种杂交体功能障碍的更大敏感性可能是由于在核和线粒体基因组中编码氧化还原中心脱辅基蛋白，这是RC复合物的独特特征。
The large number of extant Muridae species provides the opportunity of investigating functional limits of nuclear/mitochondrial respiratory chain (RC) subunit interactions by introducing mitochondrial genomes from progressively more divergent species into Mus musculus domesticus mtDNA-less (rho(0)) cells. We created a panel of such xenomitochondrial cybrids, using as mitochondrial donors cells from six murid species with divergence from M. m. domesticus estimated at 2 to 12 Myr before present. Species used were Mus spretus, Mus caroli, Mus dunni, Mus pahari, Otomys irroratits, and Rattus norvegicus. Parsimony analysis of partial mtDNA sequences showed agreement with previous molecular phylogenies, with the exception that Otomys did not nest within the murinae as suggested by some recent nuclear gene analyses. Cellular production of lactate, a sensitive indicator of decreased respiratory chain ATP production, correlated with divergence. Functional characterization of the chimeric RC complexes in isolated mitochondria using enzymological analyses demonstrated varying decreases in activities of complexes I, III, and IV, which have subunits encoded in both mitochondrial and nuclear genomes. Complex III showed a striking decline in electron transfer function in the most divergent xenocybrids, being greatly reduced in the Rattus xenocybrid and virtually absent in the Otomys xenocybrid. This suggests that nuclear subunits interacting with cytochrome b face the greatest constraints in the coevolution of murid RC subunits. We sequenced the cytochrome b gene from the species used to identify potential amino acid substitutions involved in such interactions. The greater sensitivity of complex III to xenocybrid dysfunction may result from the encoding of redox center apoproteins in both nuclear and mitochondrial genomes, a unique feature of this RC complex.