title: The regulation of CD95 (Fas) ligand expression in primary T cells: induction of promoter activation in CD95LP-Luc transgenic mice.
abstract: The interaction between CD95 (Fas) and CD95L (Fas ligand) initiates apoptosis in a variety of cell types. Although the regulation of CD95L expression on activated T cells is an area of intense study, knowledge related to the induction of CD95L promoter activity in primary T cells is lacking. In this report we describe the generation of a novel transgenic mouse strain, CD95LP-Luc, in which murine CD95L promoter sequence controls the expression of a luciferase reporter gene. We use these mice to illustrate several important findings related to transcriptional regulation of CD95L in primary T cells. We demonstrate that maximal CD95L promoter activity occurs only after prolonged T cell stimulation and requires costimulation through CD28. We provide evidence that thymocytes express CD95L/luciferase after strong TCR ligation and that inducible CD95L promoter activation is present, but unequal, in both Th1 and Th2 effector cells. We also illustrate that while agonist peptide presentation by APCs generates robust proliferation during a primary T cell response, the same stimulus induces only modest CD95L promoter activity. These results suggest alternate explanations for the well-characterized delay in CD95-mediated activation-induced cell death following initial ligation of the TCR.
authors.affiliation: Interdisciplinary Graduate Program in Immunology, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Norian
authors.forename: K M
authors.initials: KM
authors.lastname: Latinis
authors.forename: S L
authors.initials: SL
authors.lastname: Eliason
authors.forename: K
authors.initials: K
authors.lastname: Lyson
authors.forename: C
authors.initials: C
authors.lastname: Yang
authors.forename: T
authors.initials: T
authors.lastname: Ratliff
authors.forename: G A
authors.initials: GA
authors.lastname: Koretzky
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D053222:Fas Ligand Protein; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D017930:Genes, Reporter / Q000276:immunology; D006801:Humans; D008024:Ligands; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008213:Lymphocyte Activation / Q000235:genetics*; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D011401:Promoter Regions, Genetic / Q000276:immunology*; D013601:T-Lymphocytes / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D018417:Th1 Cells / Q000201:enzymology / Q000276:immunology; D018418:Th2 Cells / Q000201:enzymology / Q000276:immunology; D019014:fas Receptor / Q000235:genetics*
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008024:Ligands; D008562:Membrane Glycoproteins; D019014:fas Receptor; D008156:Luciferases