title: Role of transcription factor Sp1 and RNA binding protein HuR in the downregulation of Dr+ Escherichia coli receptor protein decay accelerating factor (DAF or CD55) by nitric oxide.
abstract: We previously reported that nitric oxide (NO) reduces the rate of bacteremia and maternal mortality in pregnant rats with uterine infection by Escherichia coli expressing the Dr Fimbria (Dr(+) ). The epithelial invasion of Dr(+) E. coli is dependent on the expression level of its cellular receptor decay accelerating factor (DAF). NO reduces the rate of bacteremia by downregulating the expression of DAF. In this study, we elucidated the role of transcription factor Sp1 and RNA binding protein HuR in the downregulation of human DAF by NO. We generated a series of deletion mutant constructs of DAF gene 5'-untranslated region and mapped the NO-response region upstream to the core promoter region of the DAF gene. One of the several Sp1 binding sites in the DAF 5'-untranslated region was located within the NO-response region. The binding of Sp1 to this site was inhibited by NO. Furthermore, NO also promoted the degradation of DAF mRNA. The 3'-untranslated region of DAF harbors an AU-rich element and this element destabilized the mRNA transcript. NO promoted the rapid degradation of DAF mRNA by inhibiting the binding of mRNA stabilizing protein HuR to this AU-rich region. The inhibition of binding of HuR to the AU-rich region was due to the S-nitrosylation of one or more cysteine residues by NO. Thus, these data reveal the molecular mediators of transcriptional and post-transcriptional regulation of DAF by NO with implications in pathophysiology related to DAF.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX 77555, USA.
authors.forename: Manu
authors.initials: M
authors.lastname: Banadakoppa
authors.forename: Daniel
authors.initials: D
authors.lastname: Liebenthal
authors.forename: David E
authors.initials: DE
authors.lastname: Nowak
authors.forename: Petri
authors.initials: P
authors.lastname: Urvil
authors.forename: Uma
authors.initials: U
authors.lastname: Yallampalli
authors.forename: Gerald M
authors.initials: GM
authors.lastname: Wilson
authors.forename: Aparna
authors.initials: A
authors.lastname: Kishor
authors.forename: Chandra
authors.initials: C
authors.lastname: Yallampalli
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D018958:CD55 Antigens / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D003545:Cysteine / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D051959:ELAV Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D036781:Fimbriae Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D009154:Mutation; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism / Q000494:pharmacology; D009603:Nitroso Compounds / Q000378:metabolism / Q000494:pharmacology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism* / Q000502:physiology
chemical_list: D020413:3' Untranslated Regions; D018958:CD55 Antigens; D051959:ELAV Proteins; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; C063055:fimbrillin; C094210:2,2'-(hydroxynitrosohydrazono)bis-ethanamine; D036781:Fimbriae Proteins; D009569:Nitric Oxide; D003545:Cysteine