title: The dual roles of Armigeres subalbatus prophenoloxidase V in parasite melanization and egg chorion melanization in the mosquito Ar. subalbatus.
abstract: Phenoloxidases (POs) play key roles in various physiological functions in insects, e.g., cuticular sclerotization, wound healing, egg tanning, cuticle formation and melanotic encapsulaction of pathogens. Previously, we identified five POs, designated As-pro-PO I-V, from the mosquito Armigeres subalbatus and demonstrated that the functions of As-pro-PO I, II and III, were associated with filarial parasite melanization, blood feeding and cuticle formation, respectively. In the present study, we delineate the dual functions of As-pro-PO V. We found that the level of As-pro-PO V mRNA in mosquitoes was significantly increased after microfilaria challenge or blood feeding, and decreased to normal level after oviposition. Knockdown of As-pro-PO V by dsRNA resulted in significant decreases in the degree of microfilaria melanization, egg chronic melanization rates and egg hatching rates in Ar. subalbatus. Further transfection and electrophoretic mobility-shift assays verified the As-pro-PO V gene might regulated by both AP-1, a putative immune-related regulatory element and CdxA, a developmental regulatory element. The binding of AP-1 and CdxA motif with mosquito nuclear extracts was significantly enhanced after microfilaria challenge and blood-feeding in Ar. subalbatus, respectively. These results indicate that As-pro-PO V is a critical enzyme that is required for both an effective melanization immune response and egg chorion melanization in this mosquito.
authors.affiliation: Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan.
authors.forename: I-Y
authors.initials: IY
authors.lastname: Tsao
authors.affiliation: Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan.
authors.forename: J-W
authors.initials: JW
authors.lastname: Chen
authors.affiliation: Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan.
authors.forename: C-J
authors.initials: CJ
authors.lastname: Li
authors.affiliation: Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan.
authors.forename: H-L
authors.initials: HL
authors.lastname: Lo
authors.affiliation: Department of Pathobiological Sciences, 1656 Linden Drive, University of Wisconsin, Madison, WI 53706, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Christensen
authors.affiliation: Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taipei 112, Taiwan. Electronic address: mosquito@ym.edu.tw.
authors.forename: C-C
authors.initials: CC
authors.lastname: Chen
mesh_terms: D000818:Animals; D001769:Blood; D004156:Catechol Oxidase / Q000235:genetics / Q000378:metabolism*; D002823:Chorion / Q000378:metabolism; D009033:Culicidae / Q000469:parasitology*; D004183:Dirofilaria immitis / Q000378:metabolism*; D004285:Dogs; D004792:Enzyme Precursors / Q000235:genetics / Q000378:metabolism*; D005260:Female; D008543:Melanins / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D004792:Enzyme Precursors; D008543:Melanins; D012333:RNA, Messenger; C038451:pro-phenoloxidase; D004156:Catechol Oxidase
keywords: Double stranded RNA-mediated RNAi; Egg chorion melanization; Gene regulation; Mosquito; Parasite melanization; Prophenoloxidase