title: Cooperative Activity of GABP with PU.1 or C/EBPε Regulates Lamin B Receptor Gene Expression, Implicating Their Roles in Granulocyte Nuclear Maturation.
abstract: Nuclear segmentation is a hallmark feature of mammalian neutrophil differentiation, but the mechanisms that control this process are poorly understood. Gene expression in maturing neutrophils requires combinatorial actions of lineage-restricted and more widely expressed transcriptional regulators. Examples include interactions of the widely expressed ETS transcription factor, GA-binding protein (GABP), with the relatively lineage-restricted E-twenty-six (ETS) factor, PU.1, and with CCAAT enhancer binding proteins, C/EBPα and C/EBPε. Whether such cooperative interactions between these transcription factors also regulate the expression of genes encoding proteins that control nuclear segmentation is unclear. We investigated the roles of ETS and C/EBP family transcription factors in regulating the gene encoding the lamin B receptor (LBR), an inner nuclear membrane protein whose expression is required for neutrophil nuclear segmentation. Although C/EBPε was previously shown to bind the Lbr promoter, surprisingly, we found that neutrophils derived from Cebpe null mice exhibited normal Lbr gene and protein expression. Instead, GABP provided transcriptional activation through the Lbr promoter in the absence of C/EBPε, and activities supported by GABP were greatly enhanced by either C/EBPε or PU.1. Both GABP and PU.1 bound Ets sites in the Lbr promoter in vitro, and in vivo within both early myeloid progenitors and differentiating neutrophils. These findings demonstrate that GABP, PU.1, and C/EBPε cooperate to control transcription of the gene encoding LBR, a nuclear envelope protein that is required for the characteristic lobulated morphology of mature neutrophils.
authors.affiliation: Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854;
authors.forename: Krishnakumar
authors.identifier: 0000-0001-6281-3347
authors.initials: K
authors.lastname: Malu
authors.affiliation: Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854;
authors.forename: Rahul
authors.identifier: 0000-0001-6120-7038
authors.initials: R
authors.lastname: Garhwal
authors.affiliation: Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854;
authors.forename: Margery G H
authors.identifier: 0000-0003-1667-589X
authors.initials: MG
authors.lastname: Pelletier
authors.affiliation: Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854;
authors.forename: Deepali
authors.initials: D
authors.lastname: Gotur
authors.affiliation: Section of Hematology, Department of Internal Medicine and Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT 06520;
authors.forename: Stephanie
authors.identifier: 0000-0002-2737-9810
authors.initials: S
authors.lastname: Halene
authors.affiliation: Department of Biochemistry, University of Zurich, 8057 Zurich, Switzerland; and.
authors.forename: Monika
authors.identifier: 0000-0001-6651-6550
authors.initials: M
authors.lastname: Zwerger
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655.
authors.forename: Zhong-Fa
authors.initials: ZF
authors.lastname: Yang
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01655.
authors.forename: Alan G
authors.initials: AG
authors.lastname: Rosmarin
authors.affiliation: Department of Biological Sciences, Biomedical Engineering and Biotechnology Program, University of Massachusetts, Lowell, MA 01854; Peter_Gaines@uml.edu.
authors.forename: Peter
authors.identifier: 0000-0002-1301-4909
authors.initials: P
authors.lastname: Gaines
mesh_terms: D000818:Animals; D022762:CCAAT-Enhancer-Binding Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology*; D002467:Cell Nucleus; D047369:Chromatin Immunoprecipitation; D024202:Electrophoretic Mobility Shift Assay; D051268:GA-Binding Protein Transcription Factor / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology*; D006098:Granulocytes / Q000166:cytology*; D057809:HEK293 Cells; D006412:Hematopoietic Stem Cells / Q000166:cytology; D006801:Humans; D015151:Immunoblotting; D051379:Mice; D008810:Mice, Inbred C57BL; D016297:Mutagenesis, Site-Directed; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis*; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators / Q000378:metabolism; D000097682:Lamin B Receptor; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D022762:CCAAT-Enhancer-Binding Proteins; D051268:GA-Binding Protein Transcription Factor; D011518:Proto-Oncogene Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D015534:Trans-Activators; D000097682:Lamin B Receptor; D000099232:Proto-Oncogene Protein Spi-1