title: Acute drug treatment in the early C. elegans embryo.
abstract: Genetic and genome-wide RNAi approaches available in C. elegans, combined with tools for visualizing subcellular events with high-resolution, have led to increasing adoption of the early C. elegans embryo as a model for mechanistic and functional genomic analysis of cellular processes. However, a limitation of this system has been the impermeability of the embryo eggshell, which has prevented the routine use of small molecule inhibitors. Here, we present a method to permeabilize and immobilize embryos for acute inhibitor treatment in conjunction with live imaging. To identify a means to permeabilize the eggshell, we used a dye uptake assay to screen a set of 310 candidate genes defined by a combination of bioinformatic criteria. This screen identified 20 genes whose inhibition resulted in >75% eggshell permeability, and 3 that permeabilized embryos with minimal deleterious effects on embryo production and early embryonic development. To mount permeabilized embryos for acute drug addition in conjunction with live imaging, we combined optimized inhibition of one of these genes with the use of a microfabricated chamber that we designed. We demonstrate that these two developments enable the temporally controlled introduction of inhibitors for mechanistic studies. This method should also open new avenues of investigation by allowing profiling and specificity-testing of inhibitors through comparison with genome-wide phenotypic datasets.
authors.affiliation: Ludwig Institute for Cancer Research, Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Ana
authors.initials: A
authors.lastname: Carvalho
authors.forename: Sara K
authors.initials: SK
authors.lastname: Olson
authors.forename: Edgar
authors.initials: E
authors.lastname: Gutierrez
authors.forename: Kelly
authors.initials: K
authors.lastname: Zhang
authors.forename: Lisa B
authors.initials: LB
authors.lastname: Noble
authors.forename: Esther
authors.initials: E
authors.lastname: Zanin
authors.forename: Arshad
authors.initials: A
authors.lastname: Desai
authors.forename: Alex
authors.initials: A
authors.lastname: Groisman
authors.forename: Karen
authors.initials: K
authors.lastname: Oegema
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D017173:Caenorhabditis elegans / Q000187:drug effects / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism; D047108:Embryonic Development / Q000187:drug effects; D007783:Lactones / Q000494:pharmacology; D015739:Nocodazole / Q000494:pharmacology; D034622:RNA Interference; D053778:Thiazolidines / Q000494:pharmacology
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D029742:Caenorhabditis elegans Proteins; D007783:Lactones; D053778:Thiazolidines; D015739:Nocodazole; C037067:latrunculin A