GENOMIC STRUCTURE, CHROMOSOMAL LOCALIZATION, START OF TRANSCRIPTION, AND TISSUE EXPRESSION OF THE HUMAN P40-PHOX, A NEW COMPONENT OF THE NICOTINAMIDE ADENINE-DINUCLEOTIDE PHOSPHATE-OXIDASE COMPLEX

p40-phox is a newly isolated cytosolic component of the nicotinamide a denine dinucleotide phosphate (NADPH)-oxidase that copurifies with p87 -phox, Although its function is not well defined, preliminary evidence indicates that it is a component of the cytosolic complex. We report the characterization of the human p40-phox gene, which is single copy and spans approximately 18 kb with 10 exons. Based on fluorescent in s itu hybridization (FISH) studies and analysis of somatic hybrid cell l ines, the chromosomal location of p40-phox is human chromosome 22q13.1 . The start of transcription has been mapped to bp -156. The expressio n of p40-phox message is restricted to hematopoietic cells. In additio n to identifying the mRNA transcript on Northern blot analysis in cell s known to express components of the NADPH-oxidase, polymorphonuclear leukocytes, monocytes, B lymphoblastoid cell lines, and eosinophils, p 40-phox is also expressed in two other cell types of white cell lineag e, mast cells, and basophils. In addition, the mRNA for p40-phox is ex pressed in megakaryocytic cells, but not in erythroid cells. (C) 1996 by The American Society of Hematology.