title: Gene silencing in Fucus embryos: developmental consequences of RNAi-mediated cytoskeletal disruption.
abstract: Brown algae (Phaeophyceae) are an important algal class that play a range of key ecological roles. They are often important components of rocky shore communities. A number of members of the Fucales and Ectocarpales have provided models for the study of multicellular evolution, reproductive biology and polarized development. Indeed the fucoid algae exhibit the unusual feature of inducible embryo polarization, allowing many classical studies of polarity induction. The potential of further studies of brown algae in these important areas has been increasingly hindered by the absence of tools for manipulation of gene expression that would facilitate further mechanistic analysis and gene function studies at a molecular level. The aim of this study was to establish a method that would allow the analysis of gene function through RNAi-mediated gene knockdown. We show that injection of double-stranded RNA (dsRNA) corresponding to an α-tubulin gene into Fucus serratus Linnaeus zygotes induces the loss of a large proportion of the microtubule cytoskeleton, leading to growth arrest and disruption of cell division. Injection of dsRNA targeting β-actin led to reduced rhizoid growth, enlarged cells and the failure to develop apical hair cells. The silencing effect on actin expression was maintained for 3 months. These results indicate that the Fucus embryo possesses a functional RNA interference system that can be exploited to investigate gene function during embryogenesis.
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK.
authors.forename: Garry
authors.initials: G
authors.lastname: Farnham
authors.affiliation: The Marine Plants and Biomolecules Laboratory, CNRS, UMR 7139, UPMC University Paris 06, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, Roscoff Cedex, 29682, France.
authors.forename: Martina
authors.initials: M
authors.lastname: Strittmatter
authors.affiliation: The Marine Plants and Biomolecules Laboratory, CNRS, UMR 7139, UPMC University Paris 06, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, Roscoff Cedex, 29682, France.
authors.forename: Susana
authors.initials: S
authors.lastname: Coelho
authors.affiliation: The Marine Plants and Biomolecules Laboratory, CNRS, UMR 7139, UPMC University Paris 06, UMR 7139, Station Biologique de Roscoff, Place Georges Teissier, BP74, Roscoff Cedex, 29682, France.
authors.forename: Jeremy Mark
authors.initials: JM
authors.lastname: Cock
authors.affiliation: Marine Biological Association, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK.|School of Ocean and Earth Sciences, University of Southampton, National Oceanography Centre, Southampton, SO14 3ZH, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Brownlee
keywords: RNAi; actin; cytoskeleton; embryo; fucus; tubulin