title: siRNA-mediated gene targeting in Aedes aegypti embryos reveals that frazzled regulates vector mosquito CNS development.
abstract: Although mosquito genome projects uncovered orthologues of many known developmental regulatory genes, extremely little is known about the development of vector mosquitoes. Here, we investigate the role of the Netrin receptor frazzled (fra) during embryonic nerve cord development of two vector mosquito species. Fra expression is detected in neurons just prior to and during axonogenesis in the embryonic ventral nerve cord of Aedes aegypti (dengue vector) and Anopheles gambiae (malaria vector). Analysis of fra function was investigated through siRNA-mediated knockdown in Ae. aegypti embryos. Confirmation of fra knockdown, which was maintained throughout embryogenesis, indicated that microinjection of siRNA is an effective method for studying gene function in Ae. aegypti embryos. Loss of fra during Ae. aegypti development results in thin and missing commissural axons. These defects are qualitatively similar to those observed in Dr. melanogaster fra null mutants. However, the Aa. aegypti knockdown phenotype is stronger and bears resemblance to the Drosophila commissureless mutant phenotype. The results of this investigation, the first targeted knockdown of a gene during vector mosquito embryogenesis, suggest that although Fra plays a critical role during development of the Ae. aegypti ventral nerve cord, mechanisms regulating embryonic commissural axon guidance have evolved in distantly related insects.
authors.affiliation: Department of Biological Sciences and Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America.
authors.forename: Anthony
authors.initials: A
authors.lastname: Clemons
authors.forename: Morgan
authors.initials: M
authors.lastname: Haugen
authors.forename: Christy
authors.initials: C
authors.lastname: Le
authors.forename: Akio
authors.initials: A
authors.lastname: Mori
authors.forename: Michael
authors.initials: M
authors.lastname: Tomchaney
authors.forename: David W
authors.initials: DW
authors.lastname: Severson
authors.forename: Molly
authors.initials: M
authors.lastname: Duman-Scheel
mesh_terms: D000330:Aedes / Q000196:embryology* / Q000235:genetics / Q000254:growth & development; D000818:Animals; D002490:Central Nervous System / Q000254:growth & development*; D029721:Drosophila Proteins; D018507:Gene Expression Regulation, Developmental; D018390:Gene Targeting / Q000379:methods*; D007303:Insect Vectors; D000075386:Netrin Receptors; D055495:Neurogenesis; D034741:RNA, Small Interfering / Q000235:genetics*; D011956:Receptors, Cell Surface / Q000032:analysis / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D000075386:Netrin Receptors; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; C000617310:fra protein, Drosophila