Aix-Marseille Univ, CNRS, Developmental Biology Institute of Marseille (IBDM), UMR 7288, Case 907, Turing Center for Living Systems, Parc Scientifique de Luminy, 13288, Marseille Cedex 09, France.
Nat Commun. 2023 Jun 2;14(1):3187. doi: 10.1038/s41467-023-38986-5.
Oxidative metabolism is the predominant energy source for aerobic muscle contraction in adult animals. How the cellular and molecular components that support aerobic muscle physiology are put in place during development through their transcriptional regulation is not well understood. Using the Drosophila flight muscle model, we show that the formation of mitochondria cristae harbouring the respiratory chain is concomitant with a large-scale transcriptional upregulation of genes linked with oxidative phosphorylation (OXPHOS) during specific stages of flight muscle development. We further demonstrate using high-resolution imaging, transcriptomic and biochemical analyses that Motif-1-binding protein (M1BP) transcriptionally regulates the expression of genes encoding critical components for OXPHOS complex assembly and integrity. In the absence of M1BP function, the quantity of assembled mitochondrial respiratory complexes is reduced and OXPHOS proteins aggregate in the mitochondrial matrix, triggering a strong protein quality control response. This results in isolation of the aggregate from the rest of the matrix by multiple layers of the inner mitochondrial membrane, representing a previously undocumented mitochondrial stress response mechanism. Together, this study provides mechanistic insight into the transcriptional regulation of oxidative metabolism during Drosophila development and identifies M1BP as a critical player in this process.
氧化代谢是成年动物有氧肌肉收缩的主要能量来源。在发育过程中,通过转录调控,支持有氧肌肉生理学的细胞和分子成分是如何被安置到位的,目前还不是很清楚。利用果蝇飞行肌模型,我们发现,在线粒体嵴中含有呼吸链的线粒体的形成,伴随着与氧化磷酸化(OXPHOS)相关的基因的大规模转录上调,这发生在飞行肌发育的特定阶段。我们进一步通过高分辨率成像、转录组和生化分析表明,基序 1 结合蛋白(M1BP)转录调控 OXPHOS 复合体组装和完整性的关键组成部分的基因表达。在缺乏 M1BP 功能的情况下,组装的线粒体呼吸复合物的数量减少,OXPHOS 蛋白在线粒体基质中聚集,引发强烈的蛋白质质量控制反应。这导致通过线粒体内膜的多层将聚集体从基质的其余部分隔离,代表了一种以前未被记录的线粒体应激反应机制。总之,这项研究为果蝇发育过程中氧化代谢的转录调控提供了机制上的见解,并确定 M1BP 是该过程中的关键参与者。