title: Genomic structures of Cyp9m10 in pyrethroid resistant and susceptible strains of Culex quinquefasciatus.
abstract: Development of insecticide resistance reduces the efficacy of controlling measures against the medical and agricultural insect pests. Cytochrome P450s are one of the major detoxification enzymes involved in insecticide metabolisms. Previously, we have reported that the P450 gene Cyp9m10 is about 260-fold overexpressed in a pyrethroid-resistant strain of Culex quinquefasciatus compared to a susceptible strain. In this study, we obtained direct evidence that the Cyp9m10 overexpression is caused by a cis-acting mutation. Additionally, a region of approximately 100 kb in length including the Cyp9m10 locus was specifically duplicated in the resistant strain. The two duplicated Cyp9m10 copies shared a completely identical sequence within the transcribed region and the flanking region up to the breakpoint located 1.1 kb upstream of the transcriptional start site. A Miniature Inverted-repeat Transposable Element (MITE)-like element was specifically inserted 0.2 kb upstream of both Cyp9m10 copies in the resistant strain. In backcross experiment, a haplotype containing the two duplicated Cyp9m10 copies was strongly associated with the pyrethroid resistance.
authors.affiliation: Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Itokawa
authors.forename: Osamu
authors.initials: O
authors.lastname: Komagata
authors.forename: Shinji
authors.initials: S
authors.lastname: Kasai
authors.forename: Yoshika
authors.initials: Y
authors.lastname: Okamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Masada
authors.forename: Takashi
authors.initials: T
authors.lastname: Tomita
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003465:Culex / Q000201:enzymology / Q000235:genetics*; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005260:Female; D020440:Gene Duplication; D006239:Haplotypes; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007305:Insecticide Resistance / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D009032:Mosquito Control; D009154:Mutation; D011722:Pyrethrins; D016415:Sequence Alignment
chemical_list: D019476:Insect Proteins; D011722:Pyrethrins; D003577:Cytochrome P-450 Enzyme System