title: Characterization and expression profile of the ovarian cytochrome P-450 aromatase (cyp19A1) gene during thermolabile sex determination in pejerrey, Odontesthes bonariensis.
abstract: Cytochrome P450 aromatase (cyp19) is an enzyme that catalyzes the conversion of androgens to estrogens and may play a role in temperature-dependent sex determination (TSD) of reptiles, amphibians, and fishes. In this study, the ovarian P450 aromatase form (cyp19A1) of pejerrey Odontesthes bonariensis, a teleost with marked TSD, was cloned and its expression profile evaluated during gonadal differentiation at feminizing (17 degrees C, 100% females), mixed-sex producing (24 and 25 degrees C, 73.3 and 26.7% females, respectively), and masculinizing (29 degrees C, 0% females) temperatures. The deduced cyp19A1 amino acid sequence shared high identity (>77.8%) with that from other teleosts but had low identity (<61.8%) with brain forms (cyp19A2), including that of pejerrey itself. The tissue distribution analysis of cyp19A1 mRNA in adult fish revealed high expression in the ovary. Semi-quantitative reverse transcription polymerase chain reaction analysis of the bodies of larvae revealed that cyp19A1 expression increased before the appearance of the first histological signs of ovarian differentiation at the feminizing temperature but remained low at the masculinizing temperature. The expression levels at mixed-sex producing temperatures were bimodal rather than intermediate, showing low and high modal values similar to those at the feminizing and masculinizing temperatures, respectively. The population percentages of high and low expression levels at intermediate temperatures were proportional to the percentage of females and males, respectively, and high levels were first observed at about the time of sex differentiation of females. These results suggest that cyp19A1 is involved in the process of ovarian formation and possibly also in the TSD of pejerrey.
authors.affiliation: Faculty of Marine Science, Department of Marine Biosciences, Tokyo University of Marine Science and Technology, Tokyo, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Karube
authors.forename: Juan Ignacio
authors.initials: JI
authors.lastname: Fernandino
authors.forename: Pablo
authors.initials: P
authors.lastname: Strobl-Mazzulla
authors.forename: Carlos Augusto
authors.initials: CA
authors.lastname: Strüssmann
authors.forename: Goro
authors.initials: G
authors.lastname: Yoshizaki
authors.forename: Gustavo Manuel
authors.initials: GM
authors.lastname: Somoza
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Patiño
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001141:Aromatase / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001831:Body Temperature / Q000235:genetics / Q000502:physiology*; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D005399:Fishes / Q000502:physiology*; D020869:Gene Expression Profiling; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000196:embryology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D012733:Sex Differentiation / Q000235:genetics / Q000502:physiology*; D012744:Sex Ratio; D013737:Testis / Q000196:embryology / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D012333:RNA, Messenger; D001141:Aromatase