Transcriptional Regulation of Platelet-Activating Factor Receptor Gene Expression in Leukocytes
Platelet-activating factor (PAF) is a potent inflammatory mediator implicated in a variety of pathophysiological states1–2. PAF exerts a wide spectrum of biological activities via binding to specific receptors present on the surface of many types of cells, including platelets, neutrophils, monocytes, eosinophils, lymphocytes, vascular endothelial cells and smooth muscle cells. A PAF receptor cDNA was first cloned from guinea pig lung by Honda et.al.3 Subsequently, two cDNAs for. human PAF receptor were cloned from leukocytes (transcript I)4–6 and heart (transcript II)7, respectively. It was shown that both human transcripts contain identical coding region, but different in the 5′-noncoding sequence, indicating that two distinct promoters are involved in the transcriptional regulation of PAF receptor gene expression in various human tissues and cells7. Nevertheless, leukocytes have been shown to express exclusively the transcript I of the PAF receptor7. In attempt to understand the molecular mechanism that directs the expression of the gene encoding the PAF receptorin leukocytes, the 5′-flanking region of the human PAF receptor for transcript I was isolated and its promoter activity was characterized in myeloid and lymphoid cell lines.
KeywordsTranscription Start Site U937 Cell Nuclear Extract Receptor Gene Expression Lymphoid Cell Line
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- 6.Kunz, D., Gerard, N.P., and Gerard, C. (1992) J. Biol. Chem. 265, 4261–4265Google Scholar