Mitochondria contain their own gene expression systems, including membrane-bound ribosomes dedicated to synthesizing a few hydrophobic subunits of the oxidative phosphorylation (OXPHOS) complexes. We used a proximity-dependent biotinylation technique, BioID, coupled with mass spectrometry to delineate in baker’s yeast a comprehensive network of factors involved in biogenesis of mitochondrial encoded proteins. This mitochondrial gene expression network (MiGENet) encompasses proteins involved in transcription, RNA processing, translation, or protein biogenesis. Our analyses indicate the spatial organization of these processes, thereby revealing basic mechanistic principles and the proteins populating strategically important sites. For example, newly synthesized proteins are directly handed over to ribosomal tunnel exit-bound factors that mediate membrane insertion, co-factor acquisition, or their mounting into OXPHOS complexes in a special early assembly hub. Collectively, the data reveal the connectivity of mitochondrial gene expression, reflecting a unique tailoring of the mitochondrial gene expression system.

线粒体含有自己的基因表达系统，包括专门用于合成氧化磷酸化 (OXPHOS) 复合物的一些疏水亚基的膜结合核糖体。我们使用邻近依赖性生物素化技术 BioID 与质谱联用，在面包酵母中描绘出参与线粒体编码蛋白质生物合成的综合因子网络。该线粒体基因表达网络 (MiGENet) 包含参与转录、RNA 加工、翻译或蛋白质生物发生的蛋白质。我们的分析表明了这些过程的空间组织，从而揭示了基本的机制原理和具有重要战略意义的位点的蛋白质。例如，新合成的蛋白质被直接移交给核糖体隧道出口结合因子，这些因子介导膜插入、辅因子获取或它们在特殊的早期组装中心中安装到 OXPHOS 复合物中。总的来说，这些数据揭示了线粒体基因表达的连通性，反映了线粒体基因表达系统的独特定制。