Characterization of a spliced variant of human IRF-3 promoter and its regulation by the transcription factor Sp1.
Interferon regulatory factor 3 (IRF-3), an essential transcriptional regulator of the interferon genes, plays an important role in host defense against viral and microbial infection as well as in cell growth regulation. Promoter plays a crucial role in gene transcription. We have reported the characterization of the wide type of human IRF-3 promoter, but the characterization of the spliced variant of human IRF-3 Int2V1 promoter has not been systematically analyzed. To observe the spliced variant of human IRF-3 promoter, we have cloned the human IRF-3 gene promoter region containing 300 nucleotides upstream the transcription start site (TSS). Transient transfection of 5' deleted promoter-reporter constructs and luciferase assay illustrated the region -159/-100 relative to the TSS is sufficient for full promoter activity. This region contains GATA1 and specific protein-1 (Sp1) transcription factor binding sites. Interestingly, mutation of this Sp1 site reduced the promoter activity by 50%. However, overexpression of Sp1 increased the transcription activity by 2.4-fold. These results indicated that the spliced variant of human IRF-3 gene core promoter was located within the region -159/-100 relative to the TSS. Sp1 transcription factor upregulates the spliced variant of human IRF-3 gene promoter.
Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China.
Wei
W
Ren
Liang-Hua
LH
Zhu
Hua-Guo
HG
Xu
Rui
R
Jin
Guo-Ping
GP
Zhou
D024506:5' Flanking Region; D001483:Base Sequence; D001665:Binding Sites; D050982:GATA1 Transcription Factor / Q000502:physiology; D017930:Genes, Reporter; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D050838:Interferon Regulatory Factor-3 / Q000235:genetics* / Q000378:metabolism; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D024363:Transcription Initiation Site; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D015854:Up-Regulation
D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D050838:Interferon Regulatory Factor-3; D020033:Protein Isoforms; D016329:Sp1 Transcription Factor; D008156:Luciferases