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Mitochondrial mutations and how to obviate them线粒体突变及其排除 The mitochondrion is a machine within the cell that does the chemistry of breathing. That is, it takes oxygen and chemically combines it with energy-rich nutrients from our food, to make carbon dioxide and water (which we exhale) and ATP, the "energy currency" of the cell. 线粒体是细胞内进行呼吸化学的一部机器。就是说，它摄取氧，把氧化学地结合于我们食物富含能量的营养物，制造二氧化碳、水（我们把它们排出）和ATP，ATP是细胞的"能量"货币。 The mitochondrion is therefore a really essential part of the cell. Lots of other parts of the cell are essential too, though, so why have a whole SENS page on it? The answer is: unlike any other part of the cell, mitochondria have their own DNA. This means that they can stop working as a result of mutations. Because the DNA is in a different place than the rest of the cell's DNA (which is in the nucleus), we need a different system to combat the inevitable accumulation of such mutations. 因此，线粒体是细胞真正重要部分。虽然细胞的其他许多部分也很重要，那么为什么要一整页的SENS来谈线粒体？回答是：线粒体不像细胞的其他部分，线粒体有它们自己的DNA。这意味着它们会因突变而停止工作。因为线粒体DNA位于不同的位置，有别于细胞其余DNA（位于细胞核中），所以，我们需要一种不同的方案来与线粒体突变不可避免的积累战斗。 As usual, we're lucky - evolution has done the hardest part of this for us already. Mitochondria are very complex -- there are about 1000 different proteins in them, each encoded by a different gene. But nearly all of those genes are not in the mitochondrion's DNA at all! -- they are in the nucleus. The proteins are constructed in the cell, outside the mitochondrion, just like all non-mitochondrial proteins. Then, a complicated apparatus called the TIM/TOM complex (no kidding...) hauls the proteins into the mitochondrion, through the membranes that make its surface. Only 13 of the mitochondrion's component proteins are encoded by its own DNA. 还是像往常一样，我们很幸运-进化已经为我们做了最困难的部分。线粒体非常复杂Ñ其中约有1000种不同的蛋白质，每一种蛋白质都由一个不同的基因编码。但是，几乎所有那些基因完全不在线粒体的DNA中！--它们在细胞核中。蛋白质在线粒体外的细胞里制造，正像所有的非线粒体蛋白质一样。然后，一种称为TIM/TOM复合物的复杂装置（不是开玩笑...）通过膜（构成线粒体的表面）把蛋白质拖进线粒体。只有13种线粒体的组成蛋白质是由线粒体自己的DNA编码的。 This gives us a wonderful opportunity: rather than fixing mitochondrial mutations, we can obviate them. We can make copies of those 13 genes, modified in fairly obvious ways so that the TIM/TOM machinery will work on them, and put these copies into the chromosomes in the nucleus. 这给了我们绝好的机会：我们可以排除它们而无需修复线粒体突变。我们可以制造那13个基因的拷贝，以好办法修饰，使得TIM/TOM装置能对它们起作用，并把这些拷贝装进细胞核的染色体。 Then, if and when the mitochondrial DNA gets mutated so that one or more of the 13 proteins are no longer being synthesised inside the mitochondria, it won't matter -- the mitochondria will be getting the same proteins from outside. Since genes in our chromosomes are very, very much better protected from mutations than the mitochondrial DNA is, we can rely on the chromosomal copies carrying on working in very nearly all our cells for much longer than a currently normal lifetime. 那么，如果线粒体DNA发生突变，以致13种蛋白质中的一种（或一种以上）不再在线粒体内被合成时，就没有什么关系了Ñ线粒体将从外部得到相同的蛋白质。因为我们染色体比线粒体DNA得到好得多的保护以防突变，所以，我们身体里几乎所有的细胞，都可以依靠染色体拷贝，比现在的正常寿命长得多地工作下去。 This project needs a lot of work, though, even though it sounds simple. The 13 proteins of interest are actually quite difficult for the TIM/TOM machinery to process even when we "tell" it to do so, so we still need to work on making that part easier. But there has been good progress in this area in the past couple of years. 这种策划需要大量的工作，虽然它听起来很简单。我们所感兴趣的13种蛋白质，实际上对于TIM/TOM装置来说，即使我们"告诉"它这么做，它也是很难处理的，所以我们仍然需要做工作，使得操作起来容易些。但是，在过去几年，在这个领域里已经有很好的进展。 Talks on this topic at IABG 10: King Aubrey de Grey's publications on this topic Aubrey de Grey用这个题目写的文章：Aubrey de Grey's publications on this topic |
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