Optimizing Wolbachia manipulation in mosquito cell lines: This proposal focuses on Wolbachia, an obligate intracellular bacterium that is widespread in arthropods, including insects that vector diseases of humans. In infected mosquitoes, Wolbachia causes a reproductive distortion known as cytoplasmic incompatibility, which provides one of the best-known biological tools for introducing transgenic mosquitoes into field populations. Because Wolbachia can be produced only within a living cell, its implementation for control purposes requires an understanding of its growth and replication, and development of transformation technologies, within the context of the mitotic cycle of its host cell.
Aim 1 describes use of mosquito cell lines that have been genetically characterized to address the hypothesis that the Wolbachia life cycle is coordinated with the mosquito cell cycle, and that Wolbachia genome replication occurs during the G1 phase of the mitotic cycle. We further hypothesize that treating Wolbachia-infected mosquito cells with chemical mutagens, specifically during the period when Wolbachia is engaged in active DNA synthesis, will enable recovery of Wolbachia mutants with selectable antibiotic resistance.
Aim 2 addresses the hypothesis that cross-talk between Wolbachia and its host cell influence the outcome of infection and overall levels of Wolbachia produced. We will use proteomics-based approaches to identify proteins, and metabolic pathways, that are differentially regulated during Wolbachia infection. Proteins to be investigated include mosquito host cell proteins and Wolbachia proteins that are secreted into the host cytoplasm and regulate cell cycle progression. Pathways that are affected by Wolbachia in cell lines will be validated in mosquito reproductive tissues.
Aim 3 addresses the hypothesis that Wolbachia can be transformed with DNA encoding a fluorescent protein and an antibiotic resistance gene by homologous recombination. For optimized recovery of transformed Wolbachia, a mosquito cell line will be made dependent on Wolbachia by engineering the riboflavin biosynthetic pathway. Experimental approaches will include cell cycle synchronization, manipulation of host cell nutrients and metabolic pathways, quantitative PCR, flow cytometry, protein identification by mass spectrometry, mutagenesis and selection of Wolbachia mutants, transformation of Wolbachia, and engineering of novel mosquito cell lines that depend on Wolbachia for survival. This work will advance use of Wolbachia as a gene drive mechanism amenable to direct genetic """"""""improvement"""""""" for control of mosquito-borne disease.

Public Health Relevance

This proposal focuses on Wolbachia, an obligate intracellular bacterium that is widespread in arthropods, including insects that vector diseases of humans. Wolbachia provides a biological method to manipulate mosquito populations and reduce disease transmission. Cultured cell lines are required for growth and manipulation of Wolbachia. We will optimize metabolic interactions between Wolbachia and mosquito host cells to maximize production and genetic manipulation of Wolbachia for control of mosquito-borne disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI081322-02
Application #
7874627
Study Section
Special Emphasis Panel (ZRG1-IDM-B (02))
Program Officer
Costero, Adriana
Project Start
2009-06-25
Project End
2014-05-31
Budget Start
2010-06-01
Budget End
2011-05-31
Support Year
2
Fiscal Year
2010
Total Cost
$327,817
Indirect Cost
Name
University of Minnesota Twin Cities
Department
Zoology
Type
Schools of Earth Sciences/Natur
DUNS #
555917996
City
Minneapolis
State
MN
Country
United States
Zip Code
55455
Baldridge, Gerald; Higgins, LeeAnn; Witthuhn, Bruce et al. (2017) Proteomic analysis of a mosquito host cell response to persistent Wolbachia infection. Res Microbiol 168:609-625
LePage, Daniel P; Metcalf, Jason A; Bordenstein, Sarah R et al. (2017) Prophage WO genes recapitulate and enhance Wolbachia-induced cytoplasmic incompatibility. Nature 543:243-247
Baldridge, Gerald D; Li, Yang Grace; Witthuhn, Bruce A et al. (2016) Mosaic composition of ribA and wspB genes flanking the virB8-D4 operon in the Wolbachia supergroup B-strain, wStr. Arch Microbiol 198:53-69
Baldridge, Gerald D; Markowski, Todd W; Witthuhn, Bruce A et al. (2016) The Wolbachia WO bacteriophage proteome in the Aedes albopictus C/wStr1 cell line: evidence for lytic activity? In Vitro Cell Dev Biol Anim 52:77-88
Fallon, Ann M (2015) Effects of mimosine on Wolbachia in mosquito cells: cell cycle suppression reduces bacterial abundance. In Vitro Cell Dev Biol Anim 51:958-63
Fallon, Ann M; Baldridge, Gerald D; Carroll, Elissa M et al. (2014) Depletion of host cell riboflavin reduces Wolbachia levels in cultured mosquito cells. In Vitro Cell Dev Biol Anim 50:707-13
Fallon, Ann M (2014) Flow cytometric evaluation of the intracellular bacterium, Wolbachia pipientis, in mosquito cells. J Microbiol Methods 107:119-25
Baldridge, Gerald D; Baldridge, Abigail S; Witthuhn, Bruce A et al. (2014) Proteomic profiling of a robust Wolbachia infection in an Aedes albopictus mosquito cell line. Mol Microbiol 94:537-56
Fallon, A M; Baldridge, G D; Higgins, L A et al. (2013) Wolbachia from the planthopper Laodelphax striatellus establishes a robust, persistent, streptomycin-resistant infection in clonal mosquito cells. In Vitro Cell Dev Biol Anim 49:66-73
Beckmann, John F; Fallon, Ann M (2013) Detection of the Wolbachia protein WPIP0282 in mosquito spermathecae: implications for cytoplasmic incompatibility. Insect Biochem Mol Biol 43:867-78

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