title: HNRNPA1 interacts with a 5'-flanking distal element of interleukin-6 and upregulates its basal transcription.
abstract: Interleukin-6 (IL-6) is an important pro-inflammatory cytokine involved in many autoimmune and inflammatory diseases. We have shown previously that a region from -5307 to -5202 bp upstream of the IL-6 transcriptional start site is responsible for basal IL-6 gene expression, and that there were DNA-binding proteins involved from electrophoretic mobility shift assay (EMSA) and transient expression experiments. Here we have combined surface plasmon resonance technology with mass spectrometry analysis and have identified nuclear proteins bound to this region. HNRNPA1 and HNRNPA2B1 were found consistently. EMSA supershift and chromatin immunoprecipitation assays confirmed the involvement of HNRNPA1, but not of HNRNPA2B1. Knocking down the HNRNPA1 expression by small interfering RNA resulted in reduced IL-6 transcriptional activity as assessed from transfection experiments using reporter constructs, mRNA and protein measurements. Overexpression of HNRNPA1 cDNA increased IL-6 mRNA expression. This regulation was dependent on the presence of the sequence from -5307 to -5202 bp of the IL-6 gene. Thus, HNRNPA1 is a novel transcriptional regulator of IL-6 expression, acting via the 5'-flanking sequence of the gene.
authors.affiliation: Division of Infection and Immunity, Department of Immunology and Molecular Pathology, Rayne Building, University College London, London, UK.
authors.forename: D
authors.initials: D
authors.lastname: Zheng
authors.forename: J
authors.initials: J
authors.lastname: Worthington
authors.forename: J F
authors.initials: JF
authors.lastname: Timms
authors.forename: P
authors.initials: P
authors.lastname: Woo
mesh_terms: D024506:5' Flanking Region; D006367:HeLa Cells; D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015854:Up-Regulation
chemical_list: D000076245:Heterogeneous Nuclear Ribonucleoprotein A1; D034481:Heterogeneous-Nuclear Ribonucleoprotein Group A-B; C508600:IL6 protein, human; D015850:Interleukin-6; D012333:RNA, Messenger; C000619656:hnRNPA1 protein, human