title: Co-option of Sox3 as the male-determining factor on the Y chromosome in the fish Oryzias dancena.
abstract: Sex chromosomes harbour a primary sex-determining signal that triggers sexual development of the organism. However, diverse sex chromosome systems have been evolved in vertebrates. Here we use positional cloning to identify the sex-determining locus of a medaka-related fish, Oryzias dancena, and find that the locus on the Y chromosome contains a cis-regulatory element that upregulates neighbouring Sox3 expression in developing gonad. Sex-reversed phenotypes in Sox3(Y) transgenic fish, and Sox3(Y) loss-of-function mutants all point to its critical role in sex determination. Furthermore, we demonstrate that Sox3 initiates testicular differentiation by upregulating expression of downstream Gsdf, which is highly conserved in fish sex differentiation pathways. Our results not only provide strong evidence for the independent recruitment of Sox3 to male determination in distantly related vertebrates, but also provide direct evidence that a novel sex determination pathway has evolved through co-option of a transcriptional regulator potentially interacted with a conserved downstream component.
authors.affiliation: 1] Laboratory of Bioresources, National Institute for Basic Biology, Okazaki 444-8585, Japan [2] Department of Basic Biology, the Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Takehana
authors.affiliation: Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Tochigi 321-8505, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Matsuda
authors.affiliation: Institute of Science and Technology, Niigata University, Niigata 950-2181, Japan.
authors.forename: Taijun
authors.initials: T
authors.lastname: Myosho
authors.affiliation: 1] Neural Circuits and Behaviour Group, Uni Research AS, Bergen 5008, Norway [2] Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Maximiliano L
authors.initials: ML
authors.lastname: Suster
authors.affiliation: 1] Division of Molecular and Developmental Biology, National Institute of Genetics, Mishima 411-8540, Japan [2] Department of Genetics, the Graduate University for Advanced Studies (SOKENDAI), Mishima 411-8540, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kawakami
authors.affiliation: Center for Genetic Resource Information, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Tadasu
authors.initials: T
authors.lastname: Shin-I
authors.affiliation: Center for Genetic Resource Information, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kohara
authors.affiliation: Department of Integrative Genomics, Tohoku Medical Megabank Organization, Sendai 980-8573, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kuroki
authors.affiliation: 1] Department of Genetics, the Graduate University for Advanced Studies (SOKENDAI), Mishima 411-8540, Japan [2] Comparative Genomics Laboratory, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Toyoda
authors.affiliation: 1] Department of Genetics, the Graduate University for Advanced Studies (SOKENDAI), Mishima 411-8540, Japan [2] Comparative Genomics Laboratory, National Institute of Genetics, Mishima 411-8540, Japan [3] National Institute of Informatics, Tokyo 101-8430, Japan.
authors.forename: Asao
authors.initials: A
authors.lastname: Fujiyama
authors.affiliation: Institute of Science and Technology, Niigata University, Niigata 950-2181, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hamaguchi
authors.affiliation: Institute of Science and Technology, Niigata University, Niigata 950-2181, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Sakaizumi
authors.affiliation: 1] Laboratory of Bioresources, National Institute for Basic Biology, Okazaki 444-8585, Japan [2] Department of Basic Biology, the Graduate University for Advanced Studies (SOKENDAI), Okazaki 444-8585, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Naruse
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D005075:Biological Evolution; D002454:Cell Differentiation / Q000502:physiology; D016386:Chromosome Walking; D022202:Chromosomes, Artificial, Bacterial; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007194:India; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009990:Oryzias / Q000235:genetics* / Q000502:physiology; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000502:physiology*; D017422:Sequence Analysis, DNA; D019849:Sex Determination Processes / Q000235:genetics* / Q000502:physiology; D013737:Testis / Q000166:cytology / Q000254:growth & development; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014998:Y Chromosome / Q000235:genetics*
chemical_list: D055748:SOXB1 Transcription Factors; D016212:Transforming Growth Factor beta