title: Ars2 maintains neural stem-cell identity through direct transcriptional activation of Sox2.
abstract: Fundamental questions remain unanswered about the transcriptional networks that control the identity and self-renewal of neural stem cells (NSCs), a specialized subset of astroglial cells that are endowed with stem properties and neurogenic capacity. Here we report that the zinc finger protein Ars2 (arsenite-resistance protein 2; also known as Srrt) is expressed by adult NSCs from the subventricular zone (SVZ) of mice, and that selective knockdown of Ars2 in cells expressing glial fibrillary acidic protein within the adult SVZ depletes the number of NSCs and their neurogenic capacity. These phenotypes are recapitulated in the postnatal SVZ of hGFAP-cre::Ars2(fl/fl) conditional knockout mice, but are more severe. Ex vivo assays show that Ars2 is necessary and sufficient to promote NSC self-renewal, and that it does so by positively regulating the expression of Sox2. Although plant and animal orthologues of Ars2 are known for their conserved roles in microRNA biogenesis, we unexpectedly observed that Ars2 retains its capacity to promote self-renewal in Drosha and Dicer1 knockout NSCs. Instead, chromatin immunoprecipitation revealed that Ars2 binds a specific region within the 6-kilobase NSC enhancer of Sox2. This association is RNA-independent, and the region that is bound is required for Ars2-mediated activation of Sox2. We used gel-shift analysis to refine the Sox2 region bound by Ars2 to a specific conserved DNA sequence. The importance of Sox2 as a critical downstream effector is shown by its ability to restore the self-renewal and multipotency defects of Ars2 knockout NSCs. Our findings reveal Ars2 as a new transcription factor that controls the multipotent progenitor state of NSCs through direct activation of the pluripotency factor Sox2.
authors.affiliation: Department of Developmental Biology, Sloan-Kettering Institute, 1275 York Avenue, Box 252, New York, New York 10065, USA. andreuac@mskcc.org
authors.forename: Celia
authors.initials: C
authors.lastname: Andreu-Agullo
authors.forename: Thomas
authors.initials: T
authors.lastname: Maurin
authors.forename: Craig B
authors.initials: CB
authors.lastname: Thompson
authors.forename: Eric C
authors.initials: EC
authors.lastname: Lai
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D017124:Conserved Sequence / Q000235:genetics; D053487:DEAD-box RNA Helicases / Q000172:deficiency; D004268:DNA-Binding Proteins; D024202:Electrophoretic Mobility Shift Assay; D004742:Enhancer Elements, Genetic / Q000235:genetics; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D058953:Neural Stem Cells / Q000166:cytology* / Q000378:metabolism*; D055495:Neurogenesis / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D009830:Olfactory Bulb / Q000166:cytology; D043244:Ribonuclease III / Q000172:deficiency; D055748:SOXB1 Transcription Factors / Q000235:genetics*; D014157:Transcription Factors / Q000737:chemistry / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D016335:Zinc Fingers
chemical_list: D004268:DNA-Binding Proteins; D005904:Glial Fibrillary Acidic Protein; D009687:Nuclear Proteins; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; C527300:Srrt protein, mouse; D014157:Transcription Factors; C509781:Dicer1 protein, mouse; C513400:Drosha protein, mouse; D043244:Ribonuclease III; D053487:DEAD-box RNA Helicases