title: Sox8 is expressed at similar levels in gonads of both sexes during the sex determining period in turtles.
abstract: A critical gene involved in mammalian sex determination and differentiation is the Sry-related gene Sox9. In reptiles, Sox9 resembles that of mammals in both structure and expression pattern in the developing gonad, but a causal role in male sex determination has not been established. A closely related gene, Sox8, is conserved in human, mouse, and trout and is expressed in developing testes and not developing ovaries in mouse. In this study, we tested the possibility of Sox8 being important for sex determination or sex differentiation in the red-eared slider turtle Trachemys scripta, in which sex is determined by egg incubation temperature between stages 15 and 20. We cloned partial turtle Sox8 and anti-Müllerian hormone (Amh) cDNAs, and analyzed the expression patterns of these genes in developing gonads by reverse transcriptase-polymerase chain reaction and whole-mount in situ hybridization. While Amh is expressed more strongly in males than in females at stage 17, Sox8 is expressed at similar levels in males and females throughout the sex-determining period. These observations suggest that differential transcription of Sox8 is not responsible for regulation of Amh, nor responsible for sex determination in turtle.
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland, Australia.
authors.forename: Shuji
authors.initials: S
authors.lastname: Takada
authors.forename: Leo
authors.initials: L
authors.lastname: DiNapoli
authors.forename: Blanche
authors.initials: B
authors.lastname: Capel
authors.forename: Peter
authors.initials: P
authors.lastname: Koopman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D054304:Anti-Mullerian Hormone; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006066:Gonads / Q000033:anatomy & histology / Q000378:metabolism*; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D055757:SOXE Transcription Factors; D016415:Sequence Alignment; D019849:Sex Determination Processes; D012733:Sex Differentiation / Q000502:physiology; D013735:Testicular Hormones / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014426:Turtles / Q000033:anatomy & histology / Q000196:embryology* / Q000502:physiology
chemical_list: D004268:DNA-Binding Proteins; D006023:Glycoproteins; C406240:SOX8 protein, human; D055757:SOXE Transcription Factors; C498639:Sox8 protein, mouse; D013735:Testicular Hormones; D014157:Transcription Factors; D054304:Anti-Mullerian Hormone