Author : Quintesia Grant
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (667 download)
Book Synopsis The Transcriptional Regulation of HLA-E by Interferon-gamma in Tumor Cells by : Quintesia Grant
Download or read book The Transcriptional Regulation of HLA-E by Interferon-gamma in Tumor Cells written by Quintesia Grant and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The human Class Ib gene, HLA-E inhibits both Natural Killer Cells and a subset of CD8+ cytotoxic T lymphocytes by engaging the CD94/NKG2A inhibitory receptor. IFN-[gamma] induces the expression of HLA-E as well as Class Ia molecules, which are required for the killing of target cells. Since HLA-E has negative effects on immune killing of target cells, we have sought to identify locus specific mechanisms of IFN-[gamma] induction in order to identify molecular targets for selective activation of Class Ia genes, but not HLA-E. We have previously identified a unique upstream IFN-[gamma] response region in the HLA-E promoter and showed that GATA-1 is required for its function in the K562 leukemic cell line. We have now examined the effect of GATA family members on IFN-[gamma] induction of HLA-E in other cell types. HLA-E CAT reporter gene assays demonstrate that tumor cells that express GATA factors as determined by western blot and quantitative PCR, mediate a 2.4 to 4.0 fold enhanced response to IFN-[gamma] stimulation. Functional constructs containing mutations of the core nucleotides in the GATA binding site had a 4.8 fold decreased response to IFN-[gamma] in A2780 cells and a 8.5 to 14.0 fold decreased response to IFN-[gamma] in SKOV3 cells. Knockdown of GATA-6 using siRNA resulted in a 40% decrease in HLA-E induction in Seg1 cells and a 30% decrease in HLA-E induction in HCT116 cells. Tetracycline regulated shRNA knockdown of GATA-6 expression in the SKOV3 cell line revealed a 3 fold decrease in the IFN-[gamma] response of HLA-E reporter driven constructs. Additionally we observed a decreased IFN-[gamma] response in SKOV3 cells transfected with siRNA specific for CBP and IRF-9. We conclude that GATA factors play a tissue specific role in regulation of IFN-[gamma] mediated HLA-E expression and that IRF-9 may be a target for the differential manipulation of classical MHC and HLA-E.