title: Mechanisms of Horizontal Cell-to-Cell Transfer of Wolbachia spp. in Drosophila melanogaster.
abstract: Wolbachiais an intracellular endosymbiont present in most arthropod and filarial nematode species. Transmission between hosts is primarily vertical, taking place exclusively through the female germ line, although horizontal transmission has also been documented. The results of several studies indicate thatWolbachiaspp. can undergo transfer between somatic and germ line cells during nematode development and in adult flies. However, the mechanisms underlying horizontal cell-to-cell transfer remain largely unexplored. Here, we establish a tractable system for probing horizontal transfer ofWolbachiacells betweenDrosophila melanogastercells in culture using fluorescencein situhybridization (FISH). First, we show that horizontal transfer is independent of cell-to-cell contact and can efficiently take place through the culture medium within hours. Further, we demonstrate that efficient transfer utilizes host cell phagocytic and clathrin/dynamin-dependent endocytic machinery. Lastly, we provide evidence that this process is conserved between species, showing that horizontal transfer from mosquito toDrosophilacells takes place in a similar fashion. Altogether, our results indicate thatWolbachiautilizes host internalization machinery during infection, and this mechanism is conserved across insect species.IMPORTANCEOur work has broad implications for the control and treatment of tropical diseases.Wolbachiacan confer resistance against a variety of human pathogens in mosquito vectors. Elucidating the mechanisms of horizontal transfer will be useful for efforts to more efficiently infect nonnatural insect hosts withWolbachiaas a biological control agent. Further, asWolbachiais essential for the survival of filarial nematodes, understanding horizontal transfer might provide new approaches to treating human infections by targetingWolbachiaFinally, this work provides a key first step toward the genetic manipulation ofWolbachia.
authors.affiliation: Department of Molecular, Cell & Developmental Biology, University of California, Santa Cruz, California, USA.
authors.forename: Pamela M
authors.initials: PM
authors.lastname: White
authors.affiliation: Department of Molecular, Cell & Developmental Biology, University of California, Santa Cruz, California, USA jose.e.pietri@gmail.com.
authors.forename: Jose E
authors.initials: JE
authors.lastname: Pietri
authors.affiliation: Jacques Monod Institute, CNRS, Paris Diderot University, Paris, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Debec
authors.affiliation: Department of Molecular, Cell & Developmental Biology, University of California, Santa Cruz, California, USA.
authors.forename: Shelbi
authors.initials: S
authors.lastname: Russell
authors.affiliation: Department of Molecular, Cell & Developmental Biology, University of California, Santa Cruz, California, USA.
authors.forename: Bhavin
authors.initials: B
authors.lastname: Patel
authors.affiliation: Department of Molecular, Cell & Developmental Biology, University of California, Santa Cruz, California, USA.
authors.forename: William
authors.initials: W
authors.lastname: Sullivan
mesh_terms: D000818:Animals; D002966:Clathrin / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology* / Q000382:microbiology* / Q000502:physiology; D034281:Dynamins / Q000378:metabolism; D005854:Germ Cells / Q000382:microbiology; D017404:In Situ Hybridization, Fluorescence; D020577:Wolbachia / Q000166:cytology / Q000502:physiology*
chemical_list: D002966:Clathrin; D034281:Dynamins
keywords: Drosophila; Wolbachia; endocytosis; entry; horizontal; invasion; phagocytosis; transfer; transmission