A bi-cistronic transcript encodes the products of both the myotrophin and leucine zipper protein 6 genes, which are located on chromosome 7. A cryptic ORF at the 3' end of the myotrophin transcript uses a novel internal ribosome entry site and a non-AUG translation initiation codon to produce leucine zipper protein 6, a 6.4 kDa tumor antigen that is associated with myeloproliferative disease. [provided by RefSeq, Jul 2008]