title: Loss of function genetic screens reveal MTGR1 as an intracellular repressor of beta1 integrin-dependent neurite outgrowth.
abstract: Integrins are transmembrane receptors that promote neurite growth and guidance. To identify regulators of integrin-dependent neurite outgrowth, here we used two loss of function genetic screens in SH-SY5Y neuroblastoma cells. First, we screened a genome-wide retroviral library of genetic suppressor elements (GSEs). Among the many genes identified in the GSE screen, we isolated the hematopoetic transcriptional factor MTGR1 (myeloid translocation gene-related protein-1). Treatment of SH-SY5Y cells with MTGR1 siRNA enhanced neurite outgrowth and concurrently increased expression of GAP-43, a protein linked to neurite outgrowth. Second, we transduced SH-SY5Y with a genome-wide GFP-labeled lentiviral siRNA library, which expressed 40,000 independent siRNAs targeting 8500 human genes. From this screen we isolated GFI1 (growth factor independence-1), which, like MTGR1, is a member of the myeloid translocation gene on 8q22 (MTG8)/ETO protein complex of nuclear repressor proteins. These results reveal novel contributions of MTGR1 and GFI1 to the regulation of neurite outgrowth and identify novel repressors of integrin-dependent neurite outgrowth.
authors.affiliation: Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA. vossovskaya@biparsciences.com <vossovskaya@biparsciences.com>
authors.forename: Valeria S
authors.initials: VS
authors.lastname: Ossovskaya
authors.forename: Gregory
authors.initials: G
authors.lastname: Dolganov
authors.forename: Allan I
authors.initials: AI
authors.lastname: Basbaum
mesh_terms: D002454:Cell Differentiation / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D005820:Genetic Testing / Q000379:methods; D005822:Genetic Vectors / Q000235:genetics; D020439:Growth Cones / Q000378:metabolism* / Q000648:ultrastructure; D006131:Growth Inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D008967:Molecular Biology / Q000379:methods; D009420:Nervous System / Q000196:embryology; D016501:Neurites / Q000378:metabolism* / Q000648:ultrastructure; D009447:Neuroblastoma; D055495:Neurogenesis / Q000235:genetics; D034622:RNA Interference / Q000502:physiology; D034741:RNA, Small Interfering / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics*; D014162:Transfection / Q000379:methods; D014407:Tumor Cells, Cultured
chemical_list: C110408:CBFA2T2 myeloid-transforming gene-related protein; D004268:DNA-Binding Proteins; C498275:GFI1 protein, human; D006131:Growth Inhibitors; D019012:Integrin beta1; D034741:RNA, Small Interfering; D012097:Repressor Proteins; D014157:Transcription Factors