Leucine Zipper Protein 6 (LUZP6)

MPD6 is a tumor antigen encoded by a cryptic ORF in the 3-prime UTR of myotrophin (MTPN) . The predicted 58-amino acid MPD6 protein has a calculated molecular mass of 6.4 kD and contains 2 overlapping leucine zippers. MPD6 is encoded in the 3-prime UTR of MTPN mRNA. Northern blot analysis detected wide expression of a 3.77-kb MPD6/MTPN transcript, with highest levels in brain, spleen, testis, and ovary. MPD6/MTPN expression was significantly upregulated in several tumor cell lines. Database and bicistronic reporter gene analyses revealed an internal ribosome entry site (IRES) upstream of MPD6 that mediated translation of the MPD6 ORF.IFNA increases IRES-mediated translation of MPD6 and that this mechanism may underlie expansion of the self-antigen repertoire involved in autoimmune and antitumor immune responses.