Abstract：
The mitochondrial genome transcribes 13 mRNAs coding for well-known proteins essential for oxidative phosphorylation. We demonstrate here that cytochrome b (CYTB), the only mitochondrial-DNA-encoded transcript among complex III, also encodes an unrecognized 187-amino-acid-long protein, CYTB-187AA, using the standard genetic code of cytosolic ribosomes rather than the mitochondrial genetic code. After validating the existence of this mtDNA-encoded protein arising from cytosolic translation (mPACT) using mass spectrometry and antibodies, we show that CYTB-187AA is mainly localized in the mitochondrial matrix and promotes the pluripotent state in primed-to-naive transition by interacting with solute carrier family 25 member 3 (SLC25A3) to modulate ATP production. We further generated a transgenic knockin mouse model of CYTB-187AA silencing and found that reduction of CYTB-187AA impairs females\' fertility by decreasing the number of ovarian follicles. For the first time, we uncovered the novel mPACT pattern of a mitochondrial mRNA and demonstrated the physiological function of this 14th protein encoded by mtDNA.
摘要：
线粒体基因组转录了13种编码氧化磷酸化所必需的众所周知的蛋白质的mRNA。我们在这里证明了细胞色素b(CYTB)，复合物III中唯一的线粒体DNA编码转录本，还编码一种未识别的187个氨基酸长的蛋白质，CYTB-187AA,使用细胞质核糖体的标准遗传密码而不是线粒体遗传密码。在使用质谱和抗体验证由胞质翻译（mPACT）产生的mtDNA编码蛋白的存在后，我们表明CYTB-187AA主要位于线粒体基质中,并通过与溶质载体家族25成员3(SLC25A3)相互作用来调节ATP的产生,从而促进从初始到初始转变的多能状态.我们进一步建立了CYTB-187AA沉默的转基因敲入小鼠模型，并发现CYTB-187AA的减少通过减少卵巢卵泡的数量来损害雌性的生育能力。第一次,我们发现了线粒体mRNA的新mPACT模式，并证明了由mtDNA编码的第14种蛋白质的生理功能。
