PU.1 as an essential activator for the expression of gp91phox gene in human peripheral neutrophils monocytes and B lymphocytes

摘要

We have reported a deficiency of a 91-kDa glycoprotein component of the phagocyte NADPH oxidase (gp91^phox) in neutrophils, monocytes, and B lymphocytes of a patient with X chromosome-linked chronic granulomatous disease. Sequence analysis of his gp91^phox gene revealed a single-base mutation (C → T) at position −53. Electrophoresis mobility-shift assays showed that both PU.1 and hematopoietic-associated factor 1 (HAF-1) bound to the inverted PU.1 consensus sequence centered at position −53 of the gp91^phox promoter, and the mutation at position −53 strongly inhibited the binding of both factors. It was also indicated that a mutation at position −50 strongly inhibited PU.1 binding but hardly inhibited HAF-1 binding, and a mutation at position −56 had an opposite binding specificity for these factors. In transient expression assay using HEL cells, which express PU.1 and HAF-1, the mutations at positions −53 and −50 significantly reduced the gp91^phox promoter activity; however, the mutation at position −56 did not affect the promoter activity. In transient cotransfection study, PU.1 dramatically activated the gp91^phox promoter in Jurkat T cells, which originally contained HAF-1 but not PU.1. In addition, the single-base mutation (C → T) at position −52 that was identified in a patient with chronic granulomatous disease inhibited the binding of PU.1 to the promoter. We therefore conclude that PU.1 is an essential activator for the expression of gp91^phox gene in human neutrophils, monocytes, and B lymphocytes.