Mitochondrial E3 Ubiquitin Ligase 1 (MUL1)

Tnrip1 was expressed only in testis, and expression was highest in testis after 14 days of age. In situ hybridization and immunohistochemical analysis detected Tnrip1 mRNA and protein in pachytene spermatocytes and round spermatids. The protein localized to nuclei.The deduced 352-amino acid protein contains 2 transmembrane domains and an evolutionarily conserved C-terminal RING finger domain. Northern blot analysis detected a 2.4-kb transcript in most tissues examined, with highest expression in heart. RT-PCR detected Mulan in isolated mouse and rat primary cardiomyocytes. Immunolocalization and sucrose gradient fractionation studies localized MULAN to mitochondria. Protease susceptibility studies suggested that the N and C termini of MULAN face the cytosol.