Sox9 in a teleost fish, medaka (Oryzias latipes): evidence for diversified function of Sox9 in gonad differentiation.
Sox9 is a transcription factor containing the Sry-related high-mobility-group (HMG) box. Mutations in human SOX9 gene cause skeletal defects and male-to-female sex reversal, indicating its essential roles in chondrogenesis and testis development. Comparative studies have shown that Sox9 is expressed in chondrogenic tissues and testis in other vertebrates. Therefore, it was suggested that roles of Sox9 in cartilage and male gonad development are conserved among vertebrates. To investigate the evolutional significance of Sox9 in the gonad and cartilage development of teleost fish, we isolated medaka sox9 and analyzed its expression. Two kinds of transcripts (sox9 and sox9lf) were isolated by cDNA library screening. The sox9 encoded 487 amino acids and showed approximately 70% amino acid identity with known vertebrate SOX9 proteins. The sox9lf was a longer form of the sox9, which was transcribed from an additional exon in the 5' upstream region. Interestingly, the expression of medaka sox9 was predominantly observed in the adult ovary by northern blot and in situ hybridization analyses, whereas in the testis, its expression was detectable only by RT-PCR. During medaka embryogenesis, its expression was observed in the cranial cartilage and pectoral fin endoskeleton. These observations suggest that the function of Sox9 in the cartilage is conserved among vertebrates, while that in the gonad is quite different in medaka.
Yokoi
Hayato
H
Division of Biological Science, Graduate School of Science, and Laboratory of Freshwater Fish Stocks, Bioscience Center, Nagoya University, Nagoya, Japan. hayokoi@lab.nig.ac.jp
Kobayashi
Tohru
T
Tanaka
Minoru
M
Nagahama
Yoshitaka
Y
Wakamatsu
Yuko
Y
Takeda
Hiroyuki
H
Araki
Kazuo
K
Morohashi
Ken-Ichirou
K
Ozato
Kenjiro
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002356:Cartilage / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005796:Genes; D006609:High Mobility Group Proteins / Q000235:genetics / Q000502:physiology*; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D009710:Nucleotide Mapping; D009928:Organ Specificity; D009990:Oryzias / Q000196:embryology / Q000502:physiology*; D010053:Ovary / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055758:SOX9 Transcription Factor; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012733:Sex Differentiation / Q000235:genetics / Q000502:physiology*; D013045:Species Specificity; D013737:Testis / Q000196:embryology / Q000254:growth & development* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
D006609:High Mobility Group Proteins; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D014157:Transcription Factors