IMMUNOCHEMICAL CHARACTERIZATION OF A NOVEL MITOCHONDRIALLY LOCATED PROTEIN ENCODED BY A NUCLEAR GENE WITHIN THE DFNB8 10 CRITICAL REGION ON21Q22.3/

A novel protein encoded by the C21ORF2 gene in chromosomal locus 21q22 .3 was characterized by immunochemistry, This chromosomal region is kn own to contain genes for human diseases such as non-syndromic autosoma l recessive deafness (DFNB8/10) and autoimmune polyendocrinopathy-cand idiasis-ectodermal dystrophy (APECED). Polyclonal murine antisera were produced against the multivalent peptides deduced from the amino acid sequence of the polypeptide, Immunological reactivity of the obtained antisera was tested with primary cells or established cell lines. On western blotting; the polyclonal sera recognized a single protein prod uct of 25 Kd expressed in cell lines of epithelial and lymphoid origin , Subsequent immunochemistry of several human tissues indicated the ub iquitous expression of the protein. Immunofluorescence studies and co- staining with a mitochondrial-specific dye suggest the subcellular loc alization of the protein to mitochondria, Mitochondrial localization i s also predicted by computer analysis of the polypeptide sequence, As deafness is known to be caused ill some instances by defects in mitoch ondrial function, C21ORF2 is a plausible candidate gene for DFNB8/10. (C) 1997 Academic Press.