title: Sex-dependent expression of anti-Müllerian hormone (amh) and amh receptor 2 during sex organ differentiation and characterization of the Müllerian duct development in Xenopus tropicalis.
abstract: Amphibian gonadal differentiation involves the action of sex steroids. Recent research indicates that the anti-Müllerian hormone (AMH) is involved in testicular development in some lower vertebrate species. For amphibians there is a lack of data on ontogenetic expression of the AMH receptor AMHR2/amhr2 and of progesterone receptors (PGRS/pgrs). Here we expand the knowledge on amphibian sex differentiation by characterizing ontogenetic mRNA levels of amh, amhr2, intracellular and membrane pgrs (ipgr and mpgr beta) and cytochrome P450 19a1 (cyp19a1) (ovarian marker) in the urogenital complex of the model species Xenopus (Silurana) tropicalis. Furthermore, we characterized the ontogenetic development of the Müllerian ducts (precursors of the female reproductive tract) histologically. The developmental period investigated spanned from beginning of gonadal differentiation, Nieuwkoop and Faber (NF) stage 51, to 4weeks post-metamorphosis. The Müllerian ducts were first observed at NF 64 in both sexes. Male-enhanced amh mRNA levels from NF 53/54 to 6days post-metamorphosis and female-enhanced cyp19a1 levels from NF 53 to 4weeks post-metamorphosis were noted. The sexually dimorphic mRNA level profile was more distinct for amh than for cyp19a1. The pgrs mRNA levels increased over the studied period and showed no sex differences. At later developmental stages, the amhr2 mRNA level was increased in putative females compared with males. Our findings suggest that AMH has a role in gonadal differentiation in X. tropicalis. We propose relative gonadal amh mRNA level as a testicular marker during early gonadal development in amphibians.
authors.affiliation: Department of Environmental Toxicology, Uppsala University, Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden. Electronic address: Erika.Jansson@ebc.uu.se.
authors.forename: Erika
authors.initials: E
authors.lastname: Jansson
authors.affiliation: Department of Environmental Toxicology, Uppsala University, Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden. Electronic address: Anna.Mattsson@ebc.uu.se.
authors.forename: Anna
authors.initials: A
authors.lastname: Mattsson
authors.affiliation: Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States. Electronic address: jgoldstone@whoi.edu.
authors.forename: Jared
authors.initials: J
authors.lastname: Goldstone
authors.affiliation: Department of Environmental Toxicology, Uppsala University, Centre for Reproductive Biology in Uppsala (CRU), Uppsala, Sweden. Electronic address: Cecilia.Berg@ebc.uu.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Berg
mesh_terms: D000818:Animals; D054304:Anti-Mullerian Hormone / Q000378:metabolism*; D002454:Cell Differentiation; D005260:Female; D008297:Male; D009095:Mullerian Ducts / Q000196:embryology*; D018000:Receptors, Peptide; D018125:Receptors, Transforming Growth Factor beta; D012733:Sex Differentiation / Q000235:genetics*; D014981:Xenopus / Q000378:metabolism*
chemical_list: D018000:Receptors, Peptide; D018125:Receptors, Transforming Growth Factor beta; C084621:anti-Mullerian hormone receptor; D054304:Anti-Mullerian Hormone
keywords: Frogs; Molecular sex marker; Müllerian inhibiting substance; Reproductive organ development; Sex differentiation