C22orf31 (chromosome 22, open reading frame 31) is a protein which in humans is encoded by the C22orf31 gene. The C22orf31 mRNA transcript has an upstream in-frame stop codon, while the protein has a domain of unknown function (DUF4662) spanning the majority of the protein-coding region. The protein has orthologs with high percent similarity in mammals. The most distant orthologs are found in species of bony fish, but C22orf31 is not found in any species of birds or amphibians.
Similar to many proteins, C22orf31 is found to be highly expressed in the testes. Analysis of in vivo mature oocytes has revealed increased levels of C22orf31 while promoter analysis has identified transcription factors for C22orf31 that are active during myeloid cell differentiation.
