Macrophage Expressed Protein 1 (MPG1)

Mpeg1 is threonine rich and shares 27.3% sequence identity with mouse perforin (PRF1) over an 88-amino acid region predicted to form 2 antiparallel amphipathic helices involved in insertion into the lipid bilayer. Northern blot analysis detected a 4.2-kb MPG1 transcript in human myelomonocytic cells, both in monocytes and peritoneal macrophages. Northern blot analysis of normal mouse tissues showed high Mpeg1 expression in macrophages and weak expression in bone marrow. Mpeg1 expression in mouse cells and cell lines was also restricted to mature macrophage and macrophage-like cells, with increased Mpeg1 expression detected as progenitor cells differentiated into macrophages.