We generated a 100-kb map of the region 5' of the PML (promyelocytic leukemia) gene on human chromosome 15q22 and identified a new gene provisionally named STORP for stomatin-related protein. The STORP gene is positioned 2 kb upstream of the PML gene in a head-to-head configuration, and contains 7 exons spanning a genomic region of about 11 kb. There is an open reading frame of 398 amino acids, which would encode a protein of 45 kD. Northern blot analysis demonstrated that the STORP gene has a ubiquitous pattern of expression similar to that of the PML gene. Hybridization of STORP cDNA probe to genomic DNA from other species demonstrated that the STORP gene is conserved among mammalian vertebrates and that the physical linkage with PML is conserved in mice. Unlike PML, the STORP gene is not induced by interferon alpha (IFNalpha), and thus can be distinctly regulated from the PML gene. STORP is homologous to the EPB72 gene coding for the erythrocyte band 7 integral membrane protein or stomatin, which is deficient in a certain form of hereditary stomatocytosis. The function of STORP is unknown. Further study will focus on studying its potential role in red cell function and disorders.