The immediate defensive reaction (by vertebrate tissue) to infection or injury caused by chemical or physical agents. The process is characterized by local vasodilation, extravasation of plasma into intercellular spaces and accumulation of white blood cells and macrophages.
Proc. Natl. Acad. Sci. U.S.A. 96, 4378-4383 (1999)[PubMed:10200270]
Human 15-lipoxygenase (h15-LO) is present on chromosome 17p13.3 in close proximity to the tumor-suppressor gene, p53. 15-LO is implicated in antiinflammation, membrane remodeling, and cancer development/metastasis. The murine BALB/c embryo fibroblast cell line, (10)1val, expresses p53 in mutant (mt) conformation when grown at 39 degrees C and in wild-type conformation when grown at 32 degrees C. Transfection of h15-LO promoter constructs (driving luciferase reporter) into (10)1val cells and into p53-deficient (10)1 cells resulted in a marked increase in h15-LO promoter activity in (10)1val cells at 39 degrees C, but not at 32 degrees C, or as compared with (10)1 cells. Transfection of h15-LO promoter deletion constructs, however, resulted in total loss of activity in both cell types at 32 degrees C and 39 degrees C. Cotransfection of (10)1 cells with h15-LO promoter (driving luciferase reporter) along with increasing levels of a mt p53 expression vector demonstrated dose-dependent capacity of mt p53 to induce 15-LO promoter activity. No effect was observed with wild-type p53. In contrast to h15-LO promoter activity, (10)1val cells had significantly lower levels of endogenous (murine) 12/15-LO (mouse analog of h15-LO) mRNA and protein when grown at 39 degrees C compared with cells grown at 32 degrees C. Our data support the hypothesis that loss of a tumor-suppressor gene (p53), or "gain-of-function activities" resulting from the expression of its mutant forms, regulates 15-LO promoter activity in man and in mouse, albeit in directionally opposite manners. The studies define a direct link between 15-LO activity and an established tumor-suppressor gene located in close chromosomal proximity.
The chemical reactions and pathways resulting in the formation of leukotriene, a pharmacologically active substance derived from a polyunsaturated fatty acid, such as arachidonic acid.
The chemical reactions and pathways involving lipids, compounds soluble in an organic solvent but not, or sparingly, in an aqueous solvent. Includes fatty acids; neutral fats, other fatty-acid esters, and soaps; long-chain (fatty) alcohols and waxes; sphingoids and other long-chain bases; glycolipids, phospholipids and sphingolipids; and carotenes, polyprenols, sterols, terpenes and other isoprenoids.
A full-length cDNA encoding 15-lipoxygenase has been isolated from a human reticulocyte cDNA library. The predicted primary structure of the enzyme exhibits a sequence similarity of 61% and 45% with human 5-lipoxygenase and the soybean lipoxygenase isoenzyme I, respectively. When all three lipoxygenases are aligned, there are two distinct regions of significant sequence identity including a cluster of five histidine residues conserved in all three lipoxygenases. Because histidines can serve as ligands for the enzymatically active iron, this region may be critical to enzymatic function. These results provide a basis for exploring functional domains of lipoxygenases.
Protein involved in the synthesis of leukotrienes, eicosanoid hormones first isolated from leukocytes. They are thought to mediate the allergic response that causes lung constriction and muscle contraction in asthma.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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