MOLECULAR-CLONING OF A NOVEL MACROPHAGE MATURATION-ASSOCIATED TRANSCRIPT ENCODING A PROTEIN WITH SEVERAL POTENTIAL TRANSMEMBRANE DOMAINS

Differentiation of tissue macrophages from bone marrow progenitor cell s via circulating blood monocytes is a complex and multistep process. In order to analyze macrophage maturation on the molecular level we us ed the method of mRNA differential display to identify novel genes tha t are preferentially expressed in mature, in vitro differentiated macr ophages. A PCR-fragment could be isolated that was amplified from macr ophages, but not from freshly isolated monocytes, and macrophage-speci fic expression was confirmed by Northern blot analysis. Several corres ponding cDNA clones could be isolated from a macrophage cDNA library, covering a nucleotide sequence of 2.5 kb. Nucleotide sequence of this cDNA showed no homology to known genes. The sequence reveals an open r eading frame that codes for a 238 amino acid hydrophobic protein with seven potential transmembrane domains, suggesting a possible role as a receptor or an ion channel. (C) 1995 Academic Press, Inc.