Functional characterization of the atopy-associated gene PHF11.
BACKGROUND
Polymorphisms in the plant homeodomain finger protein 11 gene (PHF11) are associated with increased total serum IgE levels, asthma, and severe atopic dermatitis (AD) in children. Although PHF11 includes a plant homeodomain, a motif often found in transcriptional regulators, the function of PHF11 has not been investigated.


OBJECTIVE
We sought to test (1) whether PHF11 regulates the transcription of genes involved in allergic disorders and (2) whether polymorphisms in PHF11 predict changes in the expression or function of this gene.


METHODS
Microarray analysis was used to examine the expression of PHF11 in different immune cell subsets, and the function of PHF11 was tested by using small interfering RNA-induced knockdown or overexpression of PHF11 in primary CD4+ T cells or Jurkat T cells. Genotype-dependent effects on PHF11 expression were tested by using an allele-specific gene expression, and the transcriptional activity of PHF11 was determined by using luciferase hybrid gene reporter assays and in vitro DNA-binding electromobility shift assays.


RESULTS
PHF11 expression was higher in T(H)1 cells relative to that in T(H)2 cells, and knockdown of PHF11 expression reduced expression of the T(H)1-type cytokines IFN-gamma and IL-2. The G-allele of a 3' untranslated region polymorphism associated with AD was correlated with reduced abundance of PHF11 RNA in T(H)1 cells, as well as an increase in a PHF11 isoform lacking exon II. Evidence was also found for a physical and functional interaction between PHF11 and the p65 subunit of nuclear factor kappaB.


CONCLUSIONS
PHF11 is a regulator of T(H)1-type cytokine gene expression. The reduction in PHF11 expression seen with an AD-associated genotype could contribute to the strong T(H)2 responses that characterize many allergic individuals.
Clarke
Emily
E
Institute for Immunology and Allergy Research, Westmead Millennium Institute, University of Sydney, Westmead, Australia.
Rahman
Nusrat
N
Page
Natalie
N
Rolph
Michael S
MS
Stewart
Graeme J
GJ
Jones
Graham J
GJ
D002648:Child; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000276:immunology; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000235:genetics* / Q000276:immunology; D019169:Jurkat Cells; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D022821:RNA Splice Sites; D034741:RNA, Small Interfering; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*; D014157:Transcription Factors / Q000235:genetics* / Q000276:immunology; D014158:Transcription, Genetic; D014162:Transfection
D004268:DNA-Binding Proteins; D016328:NF-kappa B; C493258:PHF11 protein, human; D022821:RNA Splice Sites; D034741:RNA, Small Interfering; D014157:Transcription Factors