title: Differential regulation of sense and antisense promoter activity at the Csf1R locus in B cells by the transcription factor PAX5.
abstract: OBJECTIVE
  The transcription factor PAX5 is essential for the activation of B-cell-specific genes and for the silencing of myeloid-specific genes. We previously determined the molecular mechanism by which PAX5 silences the myeloid-specific colony-stimulating-factor-receptor (Csf1R) gene and showed that PAX5 directly binds to the Csf1r promoter as well as to an intronic enhancer that generates an antisense transcript in B cells. Here we examine the role of PAX5 in the regulation of sense and antisense transcription in B cells.
  
  
  METHODS
  We performed PAX5-specific chromatin immunoprecipitation analyses across the Csfr1 locus. We investigated the role of PAX5 in regulating Csf1r sense and antisense promoter activity by transient transfections and by employing a Pax5(-/-) pro-B-cell line expressing an inducible PAX5 protein. PAX5 interacting factors were identified by pull-down experiments. The role of the transcription factor Sp3 in driving antisense promoter expression was examined in B cells from Sp3 knockout mice.
  
  
  RESULTS
  PAX5 differentially regulates the Csf1r promoter and the promoter of the antisense transcript. PAX5 interferes with PU.1 transactivation at the sense promoter by binding to a PAX5 consensus sequence. At the antisense promoter, PAX5 does not specifically recognize DNA, but interacts with Sp3 to upregulate antisense promoter activity. Antisense promoter activation by PAX5 is dependent on the presence of its partial homeo-domain.
  
  
  CONCLUSIONS
  We demonstrate that PAX5 regulates Csf1r in B cells by reducing the frequency of binding of the basal transcription machinery to the promoter and by activating antisense RNA expression.
authors.affiliation: Section of Experimental Haematology, Leeds Institute of Molecular Medicine, University of Leeds, Leeds, UK.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Ingram
authors.forename: Stephanie
authors.initials: S
authors.lastname: Valeaux
authors.forename: Nicola
authors.initials: N
authors.lastname: Wilson
authors.forename: M Amine
authors.initials: MA
authors.lastname: Bouhlel
authors.forename: Deborah
authors.initials: D
authors.lastname: Clarke
authors.forename: Imme
authors.initials: I
authors.lastname: Krüger
authors.forename: Divine
authors.initials: D
authors.lastname: Kulu
authors.forename: Guntram
authors.initials: G
authors.lastname: Suske
authors.forename: Sjaak
authors.initials: S
authors.lastname: Philipsen
authors.forename: Hiromi
authors.initials: H
authors.lastname: Tagoh
authors.forename: Constanze
authors.initials: C
authors.lastname: Bonifer
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D016373:DNA, Antisense / Q000235:genetics; D005786:Gene Expression Regulation; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D051757:PAX5 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011485:Protein Binding; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000235:genetics*; D051705:Sp3 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D016373:DNA, Antisense; D051757:PAX5 Transcription Factor; D011518:Proto-Oncogene Proteins; D016186:Receptor, Macrophage Colony-Stimulating Factor; D051705:Sp3 Transcription Factor; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1; C497122:Sp3 protein, mouse