title: A novel transforming growth factor-beta superfamily member expressed in gonadal somatic cells enhances primordial germ cell and spermatogonial proliferation in rainbow trout (Oncorhynchus mykiss).
abstract: Our understanding of the molecular mechanisms of primordial germ cell (PGC) proliferation in fish is rudimentary, but it is thought to be controlled by the surrounding somatic cells. We assumed that growth factors that are specifically involved in PGC proliferation are expressed predominantly in the surrounding genital ridge somatic cells. In order to isolate these growth factors, we compiled a complementary DNA (cDNA) subtractive library using cDNA from the genital ridges of 40-dpf rainbow trout embryos as the tester and cDNA from embryos without genital ridges as the driver. This approach identified a novel cytokine, designated gonadal soma-derived growth factor (GSDF), which is a member of the transforming growth factor (TGF)-beta superfamily. GSDF was expressed in the genital ridge somatic cells surrounding the PGCs during embryogenesis, and in both the granulosa and Sertoli cells at later stages. Inhibition of GSDF translation by antisense oligonucleotides suppressed PGC proliferation. Moreover, isolated testicular cells that were cultured with recombinant GSDF demonstrated dose-dependent proliferation of type-A spermatogonia; this effect was completely blocked by antiserum against GSDF. These results denote that GSDF, a novel member of the TGF-beta superfamily, plays an important role for proliferation of PGC and spermatogonia.
authors.affiliation: Department of Marine Biosciences, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Tokyo, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Sawatari
authors.forename: Shinya
authors.initials: S
authors.lastname: Shikina
authors.forename: Toshio
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Goro
authors.initials: G
authors.lastname: Yoshizaki
mesh_terms: D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense; D017686:Oncorhynchus mykiss / Q000196:embryology*; D010802:Phylogeny; D013093:Spermatogonia / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D016376:Oligonucleotides, Antisense; D016212:Transforming Growth Factor beta