Alternative titles; symbols
HGNC Approved Gene Symbol: MRPS31
Cytogenetic location: 13q14.11 Genomic coordinates (GRCh38): 13:40,729,128-40,771,190 (from NCBI)
Mitochondria have their own translation system for production of 13 inner membrane proteins essential for oxidative phosphorylation. MRPS31 is a component of the small subunit of the mitochondrial ribosome that is encoded by the nuclear genome (Koc et al., 2001).
Arden et al. (1996) cloned mouse Mrps31, which they called imogen-38. The deduced 384-amino acid protein has a 54-amino acid N-terminal mitochondrial import signal. Northern blot analysis detected variable imogen-38 expression in all mouse tissues examined. In vitro translation and transfection experiments suggested that the protein is synthesized as a 44-kD protein that is processed to the native 38-kD form. Centrifugation experiments and immunofluorescence studies confirmed mitochondrial localization of imogen-38.
By proteolytic digestion of whole bovine 28S subunits, followed by peptide analysis and EST database analysis, Koc et al. (2001) identified full-length human MRPS31. The deduced 395-amino acid protein has a calculated molecular mass of 45.3 kD. Removal of a predicted 67-amino acid N-terminal mitochondrial localization signal results in a mature 37.9-kD protein. Koc et al. (2001) identified MRPS31 orthologs in mouse and Drosophila, but not in C. elegans, yeast, or E. coli. Mouse and human MRPS31 share 66.7% amino acid identity.
Cell-mediated autoimmune attack against 38-kD islet proteins is associated with human diabetes and animal models of diabetes. Arden et al. (1996) identified imogen-38 as one such antigen in mouse. Membrane preparations from COS-7 cells transfected with imogen-38 cDNA elicited a proliferative response from a reporter human diabetic T-cell line. Arden et al. (1996) identified an 11-amino acid sequence of imogen-38 as the minimal antigenic epitope. They concluded that imogen-38 is a target for bystander autoimmune attack in diabetes rather than a primary autoantigen.
Zhang and Gerstein (2003) determined that the MRPS31 gene contains 7 exons and spans at least 41.9 kb.
By genomic sequence analysis, Zhang and Gerstein (2003) mapped the MRPS31 gene to chromosome 13q13.3. They identified 4 MRPS31 pseudogenes on chromosome 13 and another MRPS31 pseudogene on chromosome 3. Database analysis suggested that 2 of the pseudogenes on chromosome 13 are transcribed.
Arden, S. D., Roep, B. O., Neophytou, P. I., Usac, E. F., Duinkerken, G., de Vries, R. R. P., Hutton, J. C. Imogen 38: a novel 38-kD islet mitochondrial autoantigen recognized by T cells from a newly diagnosed type 1 diabetic patient. J. Clin. Invest. 97: 551-561, 1996. [PubMed: 8567980] [Full Text: https://doi.org/10.1172/JCI118448]
Koc, E. C., Burkhart, W., Blackburn, K., Moseley, A., Spremulli, L. L. The small subunit of the mammalian mitochondrial ribosome: identification of the full complement of ribosomal proteins present. J. Biol. Chem. 276: 19363-19374, 2001. [PubMed: 11279123] [Full Text: https://doi.org/10.1074/jbc.M100727200]
Zhang, Z., Gerstein, M. Identification and characterization of over 100 mitochondrial ribosomal protein pseudogenes in the human genome. Genomics 81: 468-480, 2003. [PubMed: 12706105] [Full Text: https://doi.org/10.1016/s0888-7543(03)00004-1]