title: PU.1 Regulates Ig Light Chain Transcription and Rearrangement in Pre-B Cells during B Cell Development.
abstract: B cell development and Ig rearrangement are governed by cell type- and developmental stage-specific transcription factors. PU.1 and Spi-B are E26-transformation-specific transcription factors that are critical for B cell differentiation. To determine whether PU.1 and Spi-B are required for B cell development in the bone marrow, Spi1 (encoding PU.1) was conditionally deleted in B cells by Cre recombinase under control of the Mb1 gene in Spib (encoding Spi-B)-deficient mice. Combined deletion of Spi1 and Spib resulted in a lack of mature B cells in the spleen and a block in B cell development in the bone marrow at the small pre-B cell stage. To determine target genes of PU.1 that could explain this block, we applied a gain-of-function approach using a PU.1/Spi-B-deficient pro-B cell line in which PU.1 can be induced by doxycycline. PU.1-induced genes were identified by integration of chromatin immunoprecipitation-sequencing and RNA-sequencing data. We found that PU.1 interacted with multiple sites in the Igκ locus, including Vκ promoters and regions located downstream of Vκ second exons. Induction of PU.1 induced Igκ transcription and rearrangement. Upregulation of Igκ transcription was impaired in small pre-B cells from PU.1/Spi-B-deficient bone marrow. These studies reveal an important role for PU.1 in the regulation of Igκ transcription and rearrangement and a requirement for PU.1 and Spi-B in B cell development.
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada.|The Centre for Human Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada; and.|Division of Genetics and Development, Children's Health Research Institute, Lawson Research Institute, London, Ontario N6C 2R5, Canada.
authors.forename: Carolina R
authors.initials: CR
authors.lastname: Batista
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada.|The Centre for Human Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada; and.
authors.forename: Stephen K H
authors.identifier: 0000-0002-0236-3273
authors.initials: SK
authors.lastname: Li
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada.|The Centre for Human Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada; and.|Division of Genetics and Development, Children's Health Research Institute, Lawson Research Institute, London, Ontario N6C 2R5, Canada.
authors.forename: Li S
authors.initials: LS
authors.lastname: Xu
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada.|The Centre for Human Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada; and.|Division of Genetics and Development, Children's Health Research Institute, Lawson Research Institute, London, Ontario N6C 2R5, Canada.
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Solomon
authors.affiliation: Department of Microbiology and Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada; rdekoter@uwo.ca.|The Centre for Human Immunology, Schulich School of Medicine and Dentistry, Western University, London, Ontario N6A 5C1, Canada; and.|Division of Genetics and Development, Children's Health Research Institute, Lawson Research Institute, London, Ontario N6C 2R5, Canada.
authors.forename: Rodney P
authors.initials: RP
authors.lastname: DeKoter
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D002454:Cell Differentiation; D004318:Doxycycline / Q000494:pharmacology; D005786:Gene Expression Regulation; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D054448:Precursor Cells, B-Lymphoid / Q000187:drug effects / Q000502:physiology*; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D004318:Doxycycline; D007147:Immunoglobulin Light Chains; D011518:Proto-Oncogene Proteins; D015534:Trans-Activators; D000099232:Proto-Oncogene Protein Spi-1