Pandey Parul, Wackowski Katherine, Dubey Ashutosh P, Read Laurie K
Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA.
Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
RNA. 2025 Jan 22;31(2):245-257. doi: 10.1261/rna.080295.124.
Uridine insertion/deletion (U-indel) RNA editing of mitochondrial transcripts is a posttranscriptional modification in kinetoplastid organisms, resulting in the generation of mature mRNAs from cryptic precursors. This RNA editing process involves a multiprotein complex holoenzyme and multiple accessory factors. Recent investigations have highlighted the pivotal involvement of accessory RNA-binding proteins (RBPs) in modulating RNA editing in , often in a transcript-specific manner. DRBD18 is a multifunctional RBP that reportedly impacts the stability, processing, export, and translation of nuclear-encoded mRNAs. However, mass spectrometry studies report DRBD18-RESC interactions, prompting us to investigate its role in mitochondrial U-indel RNA editing. In this study, we demonstrate the specific and RNase-sensitive interaction of DRBD18 with multiple RESC factors. Depletion of DRBD18 through RNA interference in procyclic form leads to a significant reduction in the levels of edited A6 and COIII mitochondrial transcripts, whereas its overexpression causes a notable increase in the abundance of these edited mRNAs. RNA immunoprecipitation/qRT-PCR analysis indicates a direct role for DRBD18 in A6 and COIII mRNA editing. We also examined the impact of arginine methylation of DRBD18 in the editing process, revealing that the hypomethylated form of DRBD18, rather than the arginine-methylated version, is essential for promoting these editing events. In conclusion, our findings demonstrate that DRBD18 directly affects the editing of A6 and COIII mRNAs, with its function being modulated by its arginine methylation status, marking the first report of a mitochondrial function for this protein and identifying it as a newly characterized RNA editing auxiliary factor.
线粒体转录本的尿苷插入/缺失（U-插入缺失）RNA编辑是动基体生物中的一种转录后修饰，可从隐蔽前体产生成熟的mRNA。这种RNA编辑过程涉及一种多蛋白复合全酶和多种辅助因子。最近的研究强调了辅助RNA结合蛋白（RBP）在调节RNA编辑中的关键作用，通常是以转录本特异性的方式。DRBD18是一种多功能RBP，据报道会影响核编码mRNA的稳定性、加工、输出和翻译。然而，质谱研究报告了DRBD18与RESC的相互作用，促使我们研究其在线粒体U-插入缺失RNA编辑中的作用。在本研究中，我们证明了DRBD18与多种RESC因子的特异性和对核糖核酸酶敏感的相互作用。通过RNA干扰在原环形式中耗尽DRBD18会导致编辑后的A6和COIII线粒体转录本水平显著降低，而其过表达会导致这些编辑后的mRNA丰度显著增加。RNA免疫沉淀/qRT-PCR分析表明DRBD18在A6和COIII mRNA编辑中起直接作用。我们还研究了DRBD18的精氨酸甲基化在编辑过程中的影响，发现DRBD18的低甲基化形式而非精氨酸甲基化形式对于促进这些编辑事件至关重要。总之，我们的研究结果表明DRBD18直接影响A6和COIII mRNA的编辑，其功能受其精氨酸甲基化状态的调节，这是该蛋白线粒体功能的首次报道，并将其鉴定为一种新发现的RNA编辑辅助因子。
