title: Characterization of gonadal soma-derived factor expression during sex change in the protogynous wrasse, Halichoeres trimaculatus.
abstract: BACKGROUND
  Sex change in fishes provides a good experimental model for understanding the mechanisms and plasticity of sex determination and differentiation. The three-spot wrasse, Halichoeres trimaculatus is a protogynous hermaphrodite. During sex change from female to male, the ovary is replaced by the testis through the degeneration of oocytes and subsequent spermatogenesis. In the present study, we cloned a cDNA-encoding gonadal soma-derived factor (GSDF) from protogynous wrasse and examined its expression pattern in the sexually mature gonads and the sex-changing gonad induced experimentally by aromatase inhibition.
  
  
  RESULTS
  Expression of gsdf was predominantly observed in the testis, and it was mainly localized to the supporting cells surrounding the spermatogonia. In the ovary, only slight expression of gsdf was observed in morphologically undifferentiated supporting cells in contact with oogonia. During sex change, strong expression of gsdf appeared first in the supporting cells surrounding the gonial germ cells before the onset of spermatogenesis. Thereafter, the expression of gsdf continually increased in the supporting cells surrounding the proliferating spermatogonia throughout the sex change.
  
  
  CONCLUSIONS
  These results suggest that gsdf is involved in the proliferation of spermatogonia and subsequent spermatogenesis in both the testis and the gonad in the early stages of sex change.
authors: Laboratory of Reproductive Biology, National Institution for Basic Biology, Okazaki, Aichi, Japan. horigu@xb3.so-net.ne.jp
authors: Ryo
authors: R
authors: Horiguchi
authors: Ryo
authors: R
authors: Nozu
authors: Toshiaki
authors: T
authors: Hirai
authors: Yasuhisa
authors: Y
authors: Kobayashi
authors: Yoshitaka
authors: Y
authors: Nagahama
authors: Masaru
authors: M
authors: Nakamura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D005260:Female; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D042341:Gonadal Hormones / Q000235:genetics* / Q000378:metabolism; D006066:Gonads / Q000254:growth & development* / Q000378:metabolism; D057850:Hermaphroditic Organisms / Q000235:genetics; D008297:Male; D008969:Molecular Sequence Data; D010473:Perciformes / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019849:Sex Determination Processes / Q000235:genetics; D013091:Spermatogenesis / Q000235:genetics; D014018:Tissue Distribution; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism
chemical_list: D029941:Fish Proteins; D042341:Gonadal Hormones; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta