tRNA是遗传信息传递过程中的重要适配因子。前体tRNA需经过一系列剪切修饰才能发挥功能，其中RNase P是tRNA5'末端成熟过程中的关键酶，其功能异常会导致基因翻译功能受阻。以往报道的RNase P是核酶复合体，由RNA亚基和蛋白亚基组成，RNA分子发挥剪切功能。最近研究发现人源线粒体RNase P不含有RNA组分，只由三个蛋白亚基MRPP1、MRPP2和MRPP3组成，MRPP3在其他亚基的辅助下发挥剪切功能；此外MRPP1/2亚复合体还具有甲基转移酶活性。临床研究表明MRPP各亚基突变会导致多种线粒体疾病。这一新型RNase P的作用机制及致病机理尚不清楚。我们希望通过结构生物学、生物化学及细胞生物学方法研究人源线粒体RNase P的结构与功能，解释其介导线粒体tRNA成熟的分子机制。该研究有望解释MRPP突变导致线粒体疾病的原因，并加深对线粒体转录及翻译功能的了解。

tRNAs plays an important role in transferring genetic information from DNA to protein. Pre-tRNAs are extensively processed to generate functional tRNAs. The maturation of tRNA is first performed by the endoribonuclease RNase P, which hydrolyzes 5' leader sequences from the pre-tRNAs. RNase P is classically consist of a main RNA segment and several proteins, and the P RNA acts as the catalytic domain. However, the newly identified human mitochondrial RNase P is unique in that it is composed of three proteins MRPP1-3. MRPP3 is active only in the presence of MRPP1 and MRPP2. Moreover, the subcomplex MRPP1/2 is sufficient for N1-methylation of both A and G of mitochondrial tRNAs. Mutations of MRPP1-3 also lead to several mitochondrial diseases. The mechanism of this newly identified RNase P is poorly understood. Here, we hope to elucidate the structural and functional mechanism of mt-RNase P in mitochondrial tRNA maturation, and provide theoretical basis for the study of the mitochondrial function and related diseases.