title: Genome-wide analysis reveals NRP1 as a direct HIF1α-E2F7 target in the regulation of motorneuron guidance in vivo.
abstract: In this study, we explored the existence of a transcriptional network co-regulated by E2F7 and HIF1α, as we show that expression of E2F7, like HIF1α, is induced in hypoxia, and because of the previously reported ability of E2F7 to interact with HIF1α. Our genome-wide analysis uncovers a transcriptional network that is directly controlled by HIF1α and E2F7, and demonstrates both stimulatory and repressive functions of the HIF1α -E2F7 complex. Among this network we reveal Neuropilin 1 (NRP1) as a HIF1α-E2F7 repressed gene. By performing in vitro and in vivo reporter assays we demonstrate that the HIF1α-E2F7 mediated NRP1 repression depends on a 41 base pairs 'E2F-binding site hub', providing a molecular mechanism for a previously unanticipated role for HIF1α in transcriptional repression. To explore the biological significance of this regulation we performed in situ hybridizations and observed enhanced nrp1a expression in spinal motorneurons (MN) of zebrafish embryos, upon morpholino-inhibition of e2f7/8 or hif1α Consistent with the chemo-repellent role of nrp1a, morpholino-inhibition of e2f7/8 or hif1α caused MN truncations, which was rescued in TALEN-induced nrp1a(hu10012) mutants, and phenocopied in e2f7/8 mutant zebrafish. Therefore, we conclude that repression of NRP1 by the HIF1α-E2F7 complex regulates MN axon guidance in vivo.
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands Department of Pediatrics, Division of Molecular Genetics, University Medical Center Groningen, University of Groningen, Groningen 9713 AV, The Netherlands a.debruin@uu.nl.
authors.forename: Alain
authors.initials: A
authors.lastname: de Bruin
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Peter W
authors.initials: PW
authors.lastname: A Cornelissen
authors.affiliation: Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands Goethe Universität Frankfurt, Buchmann Institute of Molecular Life Sciences (BMLS), Neural and Vascular Guidance group, D-60438 Frankfurt am Main, Germany.
authors.forename: Bettina C
authors.initials: BC
authors.lastname: Kirchmaier
authors.affiliation: Division of Pediatrics, Wilhelmina Children's Hospital, University Medical Center Utrecht, 3508 AB Utrecht, The Netherlands.
authors.forename: Michal
authors.initials: M
authors.lastname: Mokry
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Elhadi
authors.initials: E
authors.lastname: Iich
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Ella
authors.initials: E
authors.lastname: Nirmala
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Kuo-Hsuan
authors.initials: KH
authors.lastname: Liang
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Anna M
authors.initials: AM
authors.lastname: D Végh
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Koen T
authors.initials: KT
authors.lastname: Scholman
authors.affiliation: Molecular Cancer Research, University Medical Center Utrecht, Universiteitsweg 100, Utrecht, 3584 CG, The Netherlands.
authors.forename: Marian J
authors.initials: MJ
authors.lastname: Groot Koerkamp
authors.affiliation: Molecular Cancer Research, University Medical Center Utrecht, Universiteitsweg 100, Utrecht, 3584 CG, The Netherlands.
authors.forename: Frank C
authors.initials: FC
authors.lastname: Holstege
authors.affiliation: Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands.
authors.forename: Edwin
authors.initials: E
authors.lastname: Cuppen
authors.affiliation: Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Center Utrecht, 3584 CT Utrecht, The Netherlands Institute for Cardiovascular Organogenesis and Regeneration, Cells-in-Motion Cluster of Excellence, University of Münster, 48149 Münster, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schulte-Merker
authors.affiliation: Department of Pathobiology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands.
authors.forename: Walbert J
authors.initials: WJ
authors.lastname: Bakker
mesh_terms: D000818:Animals; D000071437:Axon Guidance / Q000235:genetics*; D001665:Binding Sites; D015687:Cell Hypoxia / Q000235:genetics; D045744:Cell Line, Tumor; D050702:E2F7 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D055106:Genome-Wide Association Study; D006367:HeLa Cells; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics* / Q000378:metabolism; D017403:In Situ Hybridization; D060172:Morpholinos / Q000235:genetics; D009046:Motor Neurons / Q000378:metabolism*; D039942:Neuropilin-1 / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics; D015027:Zebrafish / Q000196:embryology / Q000235:genetics*
chemical_list: D050702:E2F7 Transcription Factor; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D060172:Morpholinos; D034741:RNA, Small Interfering; D039942:Neuropilin-1