title: Temporal and spatial SOX9 expression patterns in the course of gonad development of the caudate amphibian Pleurodeles waltl.
abstract: The SOX family of transcription factors is thought to regulate gene expression in a wide variety of developmental processes. Namely, SOX9 expression is conserved in vertebrate sex determination or differentiation. Nevertheless, information about caudate amphibians is lacking. In this study, we provide data on Pleurodeles waltl, a species that displays a ZZ/ZW genetic mode of sex determination and a temperature-dependent mechanism of female-to-male sex reversal. Phylogenetic analysis of SOX9 P. waltl ortholog reveals that the deduced protein segregates from the group of anuran and could be more closely related to amniote than to anamniote. However, SOX9 lacks the PQA-rich domain present in amniotes. In larvae, SOX9 is expressed in both sexes in gonad-mesonephros complexes as soon as stage 42, before gonad differentiation. At stage 54(60d) at which testis differentiation is already in progress, analyses of isolated gonads reveal a male-enriched expression of SOX9, which was quantified by real-time PCR. At the end of metamorphosis (stage 56), SOX9 shows a nuclear localization only in the testis. In adults, SOX9 is still expressed in testes and ovaries. In the ovary, SOX9 is found in oocytes from stage I to stage VI but it is never detected in the nucleus. Our results suggest that in P. waltl, like in non mammalian vertebrates, SOX9 could play a role during the late phase of gonad differentiation rather than in sex determination. Its role in germ cells of the adult ovary has still to be elucidated.
authors.affiliation: EA 4421: Signalisation Genomique et Recherche Translationnelle en Oncologie, Nancy-Université, Nancy, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Dumond
authors.forename: Imane
authors.initials: I
authors.lastname: Al-Asaad
authors.forename: Amand
authors.initials: A
authors.lastname: Chesnel
authors.forename: Dominique
authors.initials: D
authors.lastname: Chardard
authors.forename: Brigitte
authors.initials: B
authors.lastname: Boizet-Bonhoure
authors.forename: Stéphane
authors.initials: S
authors.lastname: Flament
authors.forename: Sandra
authors.initials: S
authors.lastname: Kuntz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007814:Larva / Q000235:genetics / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010053:Ovary / Q000196:embryology / Q000378:metabolism*; D010802:Phylogeny; D010999:Pleurodeles / Q000196:embryology* / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055758:SOX9 Transcription Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012727:Sex Characteristics; D013737:Testis / Q000196:embryology / Q000378:metabolism*; D013997:Time Factors
chemical_list: D055758:SOX9 Transcription Factor