Chen Baoyin, Wang Junjun, Huang Manna, Gui Yuanye, Wei Qingqing, Wang Le, Tan Bao-Cai
Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, China.
College of Agriculture, and State Key Laboratory of Crop Biology, Shangdong Agricultural University, Tai'an, China.
PLoS Genet. 2024 Oct 2;20(10):e1011419. doi: 10.1371/journal.pgen.1011419. eCollection 2024 Oct.
C1-FDX (Complex I-ferredoxin) has been defined as a component of CI in a ferredoxin bridge in Arabidopsis mitochondria. However, its full function remains to be addressed. We created two c1-fdx mutants in Arabidopsis using the CRISPR-Cas9 methodology. The mutants show delayed seed germination. Over-expression of C1-FDX rescues the phenotype. Molecular analyses showed that loss of the C1-FDX function decreases the abundance and activity of both CI and subcomplexes of CV. In contrast, the over-expression of C1-FDX-GFP enhances the CI* (a sub-complex of CI) and CV assembly. Immunodetection reveals that the stoichiometric ratio of the α:β subunits in the F1 module of CV is altered in the c1-fdx mutant. In the complemented mutants, C1-FDX-GFP was found to be associated with the F' and α/β sub-complexes of CV. Protein interaction assays showed that C1-FDX could interact with the β, γ, δ, and ε subunits of the F1 module, indicating that C1-FDX, a structural component of CI, also functions as an assembly factor in the assembly of F' and α/β sub-complexes of CV. These results reveal a new role of C1-FDX in the CI and CV assembly and seed germination in Arabidopsis.
C1-FDX（复合体I-铁氧化还原蛋白）已被定义为拟南芥线粒体中铁氧化还原蛋白桥中复合体I的一个组成部分。然而，其完整功能仍有待研究。我们使用CRISPR-Cas9方法在拟南芥中创建了两个c1-fdx突变体。这些突变体种子萌发延迟。C1-FDX的过表达挽救了该表型。分子分析表明，C1-FDX功能的丧失会降低复合体I和复合体V亚复合体的丰度和活性。相反，C1-FDX-GFP的过表达增强了复合体I*（复合体I的一个亚复合体）和复合体V的组装。免疫检测显示，c1-fdx突变体中复合体V的F1模块中α:β亚基的化学计量比发生了改变。在互补突变体中，发现C1-FDX-GFP与复合体V的F'和α/β亚复合体相关。蛋白质相互作用分析表明，C1-FDX可以与F1模块的β、γ、δ和ε亚基相互作用，这表明C1-FDX作为复合体I的一个结构成分，在复合体V的F'和α/β亚复合体组装中也起着组装因子的作用。这些结果揭示了C1-FDX在拟南芥复合体I和复合体V组装以及种子萌发中的新作用。
