Conserved Anti-Müllerian Hormone: Anti-Müllerian Hormone Type-2 Receptor Specific Interaction and Intracellular Signaling in Teleosts1

Abstract

In higher vertebrates, anti-Müllerian hormone (AMH) is required for Müllerian duct regression in fetal males. AMH is also produced during postnatal life in both sexes regulating steroidogenesis and early stages of folliculogenesis. Teleosts lack Müllerian ducts, but Amh has been identified in several species including European sea bass. However, information on Amh type-2 receptor (Amhr2), the specific receptor for Amh binding, is restricted to a couple of fish species. Here, we report on cloning sea bass amhr2, the production of a recombinant sea bass Amh, and the functional analysis of this ligand-receptor couple. Phylogenetic analysis revealed that sea bass amhr2 segregates with Amhr2 from other vertebrates. This piscine receptor is capable of activating Smad proteins. Antibodies raised against sea bass Amh were used to study native and recombinant Amh, revealing proteins in the range of 66-70 kDa corresponding to the full length Amh. Once proteolytically treated, recombinant sea bass Amh generates a 12 kDa C-terminal mature protein, suggesting that contrary to what has been described for other fish Amh proteins, this protein is processed in a similar way as mammalian AMH. The mature sea bass Amh is a biologically active protein able to bind sea bass Amhr2 and, surprisingly, also human AMHR2. In prepubertal sea bass testes, Amh was detected by immunohistochemistry mostly in Sertoli cells surrounding early germ-cell generations. During spermatogenesis, a weaker staining signal could be observed in Sertoli cells surrounding spermatocytes.

Expression profile of amh/Amh during bi-directional sex change in the protogynous orange-spotted grouper Epinephelus coioides

“…These detected grouper Amh proteins were bigger than the theoretical size (53.4-kDa). These unexpected/alternative processings of grouper Amh in comparison to mammalian Amh were also observed in zebrafish (two candidate full-length Amh proteins of 66 and 71 kDa) [ 23 ], black porgy (two candidate full-length Amh proteins of 62 and 55 kDa) [ 24 ] and European sea bass (two candidate full-length Amh proteins of 68 and 58 kDa) [ 31 ] ( S4 Fig ). In zebrafish, in vitro plasmin-treated Amh shows the different cleavage pattern (more than one cleavage site) compared with human AMH [ 23 ].…”

Dynamic epimarks in sex-related genes predict gonad phenotype in the European sea bass, a fish with mixed genetic and environmental sex determination

“…Besides, we show the importance of taking variation into account. Further, we show that other genes the expression of which may be dimorphic during sex differentiationfor example, foxl2 is more expressed in developing ovaries [64] whereas amh-r2 is more expressed in developing testes [65] did not really show sex-specific differences in methylation. These findings suggest that either not all differences in expression are regulated via DNA methylation changes or that differences in expression regulated Figure 6.…”

The rise and fall of the ancient northern pike master sex determining gene

“…Even though amhby is an ancient and conserved MSD gene, this old MSD gene experienced different fates across the Esocidae lineage. One of these unexpected fates is the evolution of the Amhby protein in N. hubbsi, and E. niger, which lack parts of the conserved C-and /or N-terminal Amh regions 21 . In these two species, amhby was significantly and almost completely sex-linked, suggesting that this gene could still function as a MSD gene.…”

“…), poeciliids, tilapiine cichlids, salmonids, and sticklebacks, in which different SD systems, sex chromosomes and MSD genes were found even in closely related species [14][15][16][17][18] . Apart from the Oryzias family [19][20][21][22][23][24][25][26][27][28][29] and the salmonids 18,[30][31][32] , however, relatively few studies have explored the evolution of SD systems and the fate of MSD genes within an entire group of closely related species.…”