title: Zebrafish Rab5 proteins and a role for Rab5ab in nodal signalling.
abstract: The RAB5 gene family is the best characterised of all human RAB families and is essential for in vitro homotypic fusion of early endosomes. In recent years, the disruption or activation of Rab5 family proteins has been used as a tool to understand growth factor signal transduction in whole animal systems such as Drosophila melanogaster and zebrafish. In this study we have examined the functions for four rab5 genes in zebrafish. Disruption of rab5ab expression by antisense morpholino oligonucleotide (MO) knockdown abolishes nodal signalling in early zebrafish embryos, whereas overexpression of rab5ab mRNA leads to ectopic expression of markers that are normally downstream of nodal signalling. By contrast MO disruption of other zebrafish rab5 genes shows little or no effect on expression of markers of dorsal organiser development. We conclude that rab5ab is essential for nodal signalling and organizer specification in the developing zebrafish embryo.
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom.
authors.forename: Emma J
authors.initials: EJ
authors.lastname: Kenyon
authors.affiliation: Champalimaud Centre for the Unknown, Fundação Champalimaud, Lisboa, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Campos
authors.affiliation: Department of Biosciences, Swansea University, Swansea SA2 8PP, United Kingdom.
authors.forename: James C
authors.initials: JC
authors.lastname: Bull
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom.
authors.forename: P Huw
authors.initials: PH
authors.lastname: Williams
authors.affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom. Electronic address: ds4@sanger.ac.uk.
authors.forename: Derek L
authors.initials: DL
authors.lastname: Stemple
authors.affiliation: Sequencing Technology Development, The Genome Analysis Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Clark
mesh_terms: D000818:Animals; D055785:Gene Knockdown Techniques; D017403:In Situ Hybridization; D008854:Microscopy, Electron; D060172:Morpholinos / Q000235:genetics; D055456:Nodal Signaling Ligands / Q000378:metabolism*; D020897:Organizers, Embryonic / Q000196:embryology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D020696:rab5 GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D060172:Morpholinos; D055456:Nodal Signaling Ligands; D020696:rab5 GTP-Binding Proteins
keywords: Nodal; Rab5; Zebrafish