Marsupial anti-Mullerian hormone gene structure, regulatory elements, and expression

Area of Science:

• Developmental Biology
• Reproductive Biology
• Genetics

Background:

• Anti-Müllerian hormone (AMH) is crucial for male sexual development, inducing Müllerian duct regression.
• In marsupials, Müllerian duct regression occurs postnatally, unlike in eutherian mammals where it's prenatal.

Purpose of the Study:

• To isolate and characterize the anti-Müllerian hormone (AMH) gene from the tammar wallaby (Macropus eugenii).
• To investigate AMH expression in the developing testes and ovaries of the tammar wallaby.
• To understand the evolutionary conservation of AMH in mammalian sex determination.

Main Methods:

• Isolation and sequencing of the tammar wallaby AMH orthologue.
• Analysis of the wallaby AMH gene's regulatory region for transcription factor binding sites.
• Examination of AMH expression patterns in developing and adult tammar wallaby testes and ovaries via immunohistochemistry.

Main Results:

• The tammar wallaby AMH gene is highly conserved, particularly the C-terminal mature domain, with a divergent N-terminus.
• The 5' regulatory region contains conserved SF1, SOX9, and GATA binding sites, plus a putative SRY-binding site.
• AMH is expressed in Sertoli cells of developing testes, coinciding with Müllerian duct regression, and in adult ovarian granulosa cells of primary/secondary follicles.

Conclusions:

• AMH expression and function are conserved across mammalian evolution, despite differences in developmental timing.
• AMH's role in Müllerian duct regression is tightly linked to upstream sex determination pathways.
• The study provides insights into marsupial reproductive development and the evolution of sex determination mechanisms.