THE CD11B PROMOTER DIRECTS HIGH-LEVEL EXPRESSION OF REPORTER GENES INMACROPHAGES IN TRANSGENIC MICE

CD11b is the alpha chain of the Mac-1 integrin and is preferentially e xpressed in myeloid cells (neutrophils, monocytes, and macrophages). W e have previously shown that the CD11b promoter directs cell-type-spec ific expression in myeloid lines using transient transfection assays. To confirm that these promoter sequences contain the proper regulatory elements for correct myeloid expression of CD11b in vivo, we have use d the -1.7-kb human CD11b promoter to direct reporter gene expression in transgenic mice, Stable founder lines were generated with two diffe rent reporter genes, a Thy 1.1 surface marker and the Escherichia coli lacZ (beta-galaclosidase) gene, Analysis of founders generated with e ach reporter demonstrated that the CD11b promoter was capable of drivi ng high levels of transgene expression in murine macrophages for the l ifetime of the animals, Similar to the endogenous gene, transgene expr ession was preferentially found in mature monocytes, macrophages, and neutrophils and not in myeloid precursors. These experiments indicate that the -1.7 CD11b promoter contains the regulatory elements sufficie nt for high-level macrophage expression. This promoter should be usefu l for targeting heterologous gene expression to mature myeloid cells. (C) 1995 by The American Society of Hematology,