Regulation of IFN consensus sequence binding protein expression in murine macrophages.
Recent work has demonstrated that the transcription factor, IFN consensus sequence binding protein (ICSBP), plays a critical role in the capacity of mice to control infection with Toxoplasma gondii and Leishmania major, agents that require highly activated macrophages for their elimination. In this report the regulation of ICSBP mRNA and protein were analyzed in murine macrophages stimulated with LPS and/or IFN-gamma. Like induction of leishmaniacidal activity, LPS and IFN-gamma synergize to induce ICSBP mRNA and protein. Deletion analysis of the ICSBP promoter identified regions that were IFN-gamma responsive, regions that mediate the ability of LPS and IFN-gamma to activate this promoter synergistically, as well as regions that normally repress ICSBP transcription. Finally, exogenous expression of ICSBP, found in previous studies to down-regulate MHC I gene expression, failed to repress basal or IFN-gamma-induced ICSBP transcription. This demonstrates that ICSBP can selectively suppress the expression of IFN-responsive genes. These findings extend in a significant way our understanding of the regulation of ICSBP by LPS and IFN-gamma and provide important clues as to its role in macrophage activation.
Kantakamalakul
W
W
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
Politis
A D
AD
Marecki
S
S
Sullivan
T
T
Ozato
K
K
Fenton
M J
MJ
Vogel
S N
SN
D000818:Animals; D002460:Cell Line; D016384:Consensus Sequence / Q000235:genetics / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000502:physiology; D004357:Drug Synergism; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D050856:Interferon Regulatory Factor-1; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D010750:Phosphoproteins / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000276:immunology; D014176:Protein Biosynthesis; D011518:Proto-Oncogene Proteins / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis; D012097:Repressor Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D017384:Sequence Deletion; D015534:Trans-Activators / Q000502:physiology; D000099185:Interferon Regulatory Factor-8; D000099232:Proto-Oncogene Protein Spi-1
D004268:DNA-Binding Proteins; D050856:Interferon Regulatory Factor-1; D050835:Interferon Regulatory Factors; D007371:Interferon-gamma; D008070:Lipopolysaccharides; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; D000099185:Interferon Regulatory Factor-8; D000099232:Proto-Oncogene Protein Spi-1; C494258:Irf1 protein, mouse