Transcriptional regulation of the human TLR9 gene.
To clarify the molecular basis of human TLR9 (hTLR9) gene expression, the activity of the hTLR9 gene promoter was characterized using the human myeloma cell line RPMI 8226. Reporter gene analysis and EMSA demonstrated that hTLR9 gene transcription was regulated via four cis-acting elements, cAMP response element, 5'-PU box, 3'-PU box, and a C/EBP site, that interacted with the CREB1, Ets2, Elf1, Elk1, and C/EBPalpha transcription factors. Other members of the C/EBP family, such as C/EBPbeta, C/EBPdelta, and C/EBPepsilon, were also important for TLR9 gene transcription. CpG DNA-mediated suppression of TLR9 gene transcription led to decreased binding of the trans-acting factors to their corresponding cis-acting elements. It appeared that suppression was mediated via c-Jun and NF-kappaB p65 and that cooperation among CREB1, Ets2, Elf1, Elk1, and C/EBPalpha culminated in maximal transcription of the TLR9 gene. These findings will help to elucidate the mechanism of TLR9 gene regulation and to provide insight into the process by which TLR9 evolved in the mammalian immune system.
Section of Retroviral Immunology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA. takesita@yokohama-cu.ac.jp
Fumihiko
F
Takeshita
Koichi
K
Suzuki
Shin
S
Sasaki
Norihisa
N
Ishii
Dennis M
DM
Klinman
Ken J
KJ
Ishii
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D022762:CCAAT-Enhancer-Binding Proteins / Q000276:immunology / Q000378:metabolism; D045744:Cell Line, Tumor; D003001:Cloning, Molecular; D018899:CpG Islands / Q000235:genetics / Q000276:immunology; D017362:Cyclic AMP Response Element-Binding Protein / Q000276:immunology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000276:immunology*; D017930:Genes, Reporter / Q000235:genetics / Q000276:immunology; D016758:Genes, jun / Q000276:immunology; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics* / Q000276:immunology; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors; D014157:Transcription Factors / Q000276:immunology* / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D015533:Transcriptional Activation / Q000276:immunology*; D014162:Transfection
D022762:CCAAT-Enhancer-Binding Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D011956:Receptors, Cell Surface; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors; D014157:Transcription Factors