title: The role of upstream stimulatory factor 1 in the transcriptional regulation of the human TBX21 promoter mediated by the T-1514C polymorphism associated with systemic lupus erythematosus.
abstract: T-bet is a key regulator for the lineage commitment in CD4+ T helper (Th) 1 cells by activating the hallmark production of interferon-γ. Previously, two single nucleotide polymorphisms (SNPs) in the TBX21 promoter, T-1993C and T-1514C, have been shown by statistic studies to associate with systemic lupus erythematosus (SLE). The effect of -1993 SNP on the Yin Yang 1 transcription factor-mediated promoter activity has been already indicated. This study aimed to investigate roles of the T-1514C SNP on TBX21 transcription and its functional effect by luciferase reporter, electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP) assay, and flow cytometric analysis of intracellular T-bet, IFN-γ, and IL-4 expression in activated CD4+ T cells. The TBX21 promoter carrying -1514C possessed significantly lower transcriptional activity than that of -1514T and was markedly downregulated by the overexpression of upstream stimulatory factor 1 (USF-1) when compared with the promoter carrying -1514T. EMSA indicated that the transcription factor USF-1 was bound to the -1514C allele probe with the affinity higher than that to the -1514T allele probe. ChIP assay suggested that USF-1 bound around -1514 of TBX21 genomic DNA in vivo in the human T cell line Jurkat with -1514C/T. The individuals carrying -1514C allele were determined to have significantly diminished expression of T-bet and IFN-γ and increased IL-4 production in CD4+ T cells compared with those of -1514T allele. The findings demonstrate that the T-1514C polymorphism affects TBX21 gene expression and Th1 cytokine production by binding USF-1 to the SNP site.
authors.affiliation: Institute of Infectious Diseases, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
authors.forename: Junggang
authors.initials: J
authors.lastname: Li
authors.forename: Jirong
authors.initials: J
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: You
authors.forename: Song
authors.initials: S
authors.lastname: Chen
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D002681:China; D016207:Cytokines / Q000096:biosynthesis; D017931:DNA Primers / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation; D005787:Gene Frequency; D006801:Humans; D055261:Immunogenetic Phenomena; D019169:Jurkat Cells; D008180:Lupus Erythematosus, Systemic / Q000235:genetics* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D020825:T-Box Domain Proteins / Q000097:blood / Q000235:genetics*; D051720:Upstream Stimulatory Factors / Q000235:genetics* / Q000378:metabolism*; D055815:Young Adult; D000098815:T-bet Transcription Factor
chemical_list: D016207:Cytokines; D017931:DNA Primers; D020825:T-Box Domain Proteins; D000098815:T-bet Transcription Factor; C497181:USF1 protein, human; D051720:Upstream Stimulatory Factors