Progestogen is a potential trigger initiating sex inversion in rice field eel (Monopterus albus)

Area of Science:

• Reproductive biology
• Endocrinology
• Genetics

Background:

• The rice field eel (Monopterus albus) is a hermaphroditic fish capable of sex inversion.
• The precise biological mechanisms underlying sex inversion in this species are not fully understood.

Purpose of the Study:

• To investigate the molecular mechanisms and hormonal regulation of sex inversion in the rice field eel.
• To identify key genetic elements and hormonal factors involved in the female-to-male sex change.

Main Methods:

• Cloning and characterization of the 5' proximal flanking region of the dmrt1 gene.
• Reporter gene assays to analyze gene regulation.
• In vitro tissue culture and progestogen hormone level assays.

Main Results:

• The cloned dmrt1 gene region contains unique progesterone response elements (PRE) and androgen response elements (ARE).
• Progestogen acts as a prerequisite for initiating sex inversion.
• Androgen plays a significant role in positively regulating the sex inversion process.

Conclusions:

• Progestogen is identified as the primary trigger for initiating sex trans-differentiation during final oocyte maturation in rice field eels.
• Androgen contributes to the positive regulation of this sex inversion process.
• This study elucidates the biological mechanism of sex inversion in Monopterus albus.