Mrps21, Mitochondrial Ribosomal Protein S21, is an essential component of the mitoribosome complex. Mitoribosomes are crucial for mitochondrial function, and Mrps21 likely plays a part in mitochondrial protein synthesis, which is vital for processes like aerobic respiration and energy production. Since mitochondrial function impacts overall cellular and organismal viability, understanding Mrps21's function is of great biological importance, and genetic models can be valuable for its study [1].

In a study on hepatocellular carcinoma (HCC), Mrps21 was among 14 mitochondrial ribosomal protein (MRP) genes significantly upregulated in tumor samples compared to normal samples, showing good diagnostic performance. Additionally, in a genome-wide identification of RNA modifications for spontaneous coronary artery dissection (SCAD), an A-to-I modification SNP (rs580060) in the 3'-UTR of Mrps21 and an m6A modification-related SNP (rs3818978) in the 5'-UTR of Mrps21 were associated with SCAD. Moreover, in a study on the progression of islet autoimmunity to type 1 diabetes, the region 1q21.3 (MRPS21-PRPF3) showed suggestive evidence of association with the disease progression. Also, in equine skeletal muscle, Mrps21 expression increased following a ten-month exercise training period [2,3,4,5].

In conclusion, Mrps21 is essential for mitoribosome function and likely mitochondrial protein synthesis. Its upregulation in HCC tumors indicates a potential role in cancer development, and the identified RNA modification-related SNPs associated with SCAD suggest a link to this cardiovascular condition. The association in type 1 diabetes progression and the change in equine muscle with exercise training further expand its potential implications in disease and physiological responses. Studies on Mrps21 using genetic models could provide more insights into these disease areas and physiological processes.