title: Microarray and RNAi analysis of P450s in Anopheles gambiae male and female steroidogenic tissues: CYP307A1 is required for ecdysteroid synthesis.
abstract: In insects, the steroid hormone 20-hydroxyecdysone (20E) coordinates major developmental transitions. While the first and the final steps of 20E biosynthesis are characterized, the pathway from 7-dehydrocholesterol to 5β-ketodiol, commonly referred as the "black box", remains hypothetical and whether there are still unidentified enzymes is unknown. The black box would include some oxidative steps, which are believed to be mediated by P450 enzymes. To identify new enzyme(s) involved in steroid synthesis, we analyzed by small-scale microarray the expression of all the genes encoding P450 enzymes of the malaria mosquito Anopheles gambiae in active steroidogenic organs of adults, ovaries from blood-fed females and male reproductive tracts, compared to inactive steroidogenic organs, ovaries from non-blood-fed females. Some genes encoding P450 enzymes were specifically overexpressed in female ovaries after a blood-meal or in male reproductive tracts but only three genes were found to be overexpressed in active steroidogenic organs of both females and males: cyp307a1, cyp4g16 and cyp6n1. Among these genes, only cyp307a1 has an expression pattern similar to other mosquito steroidogenic genes. Moreover, loss-of-function by transient RNAi targeting cyp307a1 disrupted ecdysteroid production demonstrating that this gene is required for ecdysteroid biosynthesis in Anopheles gambiae.
authors: Biogenèse des Stéroïdes, FRE2852, CNRS-UPMC, Paris, France ; Unit of Insect Vector Genetics and Genomics, Department of Parasitology and Mycology, CNRS Unit URA3012: Hosts, Vectors and Infectious Agents, Institut Pasteur, Paris, France.
authors: Emilie
authors: E
authors: Pondeville
authors: Jean-Philippe
authors: JP
authors: David
authors: Emilie
authors: E
authors: Guittard
authors: Annick
authors: A
authors: Maria
authors: Jean-Claude
authors: JC
authors: Jacques
authors: Hilary
authors: H
authors: Ranson
authors: Catherine
authors: C
authors: Bourgouin
authors: Chantal
authors: C
authors: Dauphin-Villemant
mesh_terms: D000818:Animals; D000852:Anopheles / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D002783:Cholestenones / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D003684:Dehydrocholesterols / Q000378:metabolism; D004441:Ecdysterone / Q000096:biosynthesis* / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D010053:Ovary / Q000201:enzymology*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D012098:Reproduction / Q000235:genetics; D013737:Testis / Q000201:enzymology*
chemical_list: D002783:Cholestenones; D065607:Cytochrome P-450 Enzyme Inhibitors; D003684:Dehydrocholesterols; D034741:RNA, Small Interfering; C007424:3 beta,14 alpha-dihydroxy-5 beta-cholest-7-en-6-one; D004441:Ecdysterone; D003577:Cytochrome P-450 Enzyme System; C016705:7-dehydrocholesterol