title: Transcription factor and microRNA interactions in lung cells: an inhibitory link between NK2 homeobox 1, miR-200c and the developmental and oncogenic factors Nfib and Myb.
abstract: BACKGROUND
  The transcription factor NK2 homeobox 1 (Nkx2-1) plays essential roles in epithelial cell proliferation and differentiation in mouse and human lung development and tumorigenesis. A better understanding of genes and pathways downstream of Nkx2-1 will clarify the multiple roles of this critical lung factor. Nkx2-1 regulates directly or indirectly numerous protein-coding genes; however, there is a paucity of information about Nkx2-1-regulated microRNAs (miRNAs).
  
  
  RESULTS
  By miRNA array analyses of mouse epithelial cell lines in which endogenous Nkx2-1 was knocked-down, we revealed that 29 miRNAs were negatively regulated including miR-200c, and 39 miRNAs were positively regulated by Nkx2-1 including miR-1195. Mouse lungs lacking functional phosphorylated Nkx2-1 showed increased expression of miR-200c and alterations in the expression of other top regulated miRNAs. Moreover, chromatin immunoprecipitation assays showed binding of NKX2-1 protein to regulatory regions of these miRNAs. Promoter reporter assays indicated that 1kb of the miR-200c 5' flanking region was transcriptionally active but did not mediate Nkx2-1- repression of miR-200c expression. 3'UTR reporter assays support a direct regulation of the predicted targets Nfib and Myb by miR-200c.
  
  
  CONCLUSIONS
  These studies suggest that Nkx2-1 controls the expression of specific miRNAs in lung epithelial cells. In particular, we identified a regulatory link between Nkx2-1, the known tumor suppressor miR-200c, and the developmental and oncogenic transcription factors Nfib and Myb, adding new players to the regulatory mechanisms driven by Nkx2-1 in lung epithelial cells that may have implications in lung development and tumorigenesis.
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. tagne@bu.edu.
authors.forename: Jean-Bosco
authors.initials: JB
authors.lastname: Tagne
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. omohtar@bu.edu.
authors.forename: Omar R
authors.initials: OR
authors.lastname: Mohtar
authors.affiliation: Section of Computational Biomedicine, Department of Medicine, Boston University School of Medicine, Boston, USA. camp@bu.edu.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Campbell
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. mnarayan@bu.edu.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Lakshminarayanan
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. huangjingshu100@hotmail.com.
authors.forename: Jingshu
authors.initials: J
authors.lastname: Huang
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. ahinds@bu.edu.
authors.forename: Anne C
authors.initials: AC
authors.lastname: Hinds
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. jl4211@columbia.edu.
authors.forename: Jining
authors.initials: J
authors.lastname: Lu
authors.affiliation: The Pulmonary Center, Boston University School of Medicine, Boston, USA. mramirez@bu.edu.|Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 72 E. Concord St, Boston, MA, 02118, USA. mramirez@bu.edu.
authors.forename: Maria I
authors.initials: MI
authors.lastname: Ramirez
mesh_terms: D020413:3' Untranslated Regions; D024506:5' Flanking Region; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D017930:Genes, Reporter; D008168:Lung / Q000378:metabolism*; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D051839:NFI Transcription Factors / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D020626:Oncogene Proteins v-myb / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D020413:3' Untranslated Regions; D035683:MicroRNAs; C543719:Mirn200 microRNA, mouse; D051839:NFI Transcription Factors; C484683:Nfib protein, mouse; C000614414:Nkx2-1 protein, mouse; D009687:Nuclear Proteins; D020626:Oncogene Proteins v-myb; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors