Mex3c mutation affects lactation through impairing milk ejection in female mice

Area of Science:

• Developmental Biology
• Genetics
• Molecular Biology

Background:

• Mex3c (MEX3 RNA-binding family member C) is an RNA-binding protein with known roles in growth and immunity.
• Alternative splicing of Mex3c generates protein variants of differing lengths.
• Previous studies linked Mex3c mutations to growth retardation, metabolic issues, and impaired innate immunity.

Purpose of the Study:

• To investigate the role of Mex3c in female reproductive physiology, specifically mammary gland development and lactation.
• To determine the underlying mechanisms of lactation defects in Mex3c-mutant mice.

Main Methods:

• Analysis of mammary gland development and lactation in Mex3c-mutant female mice.
• Assessment of milk content, ductal and alveolar milk presence, and pup survival.
• Evaluation of key hormonal levels (prolactin, oxytocin) and myoepithelial cell development.
• Expression analysis of Mex3c in mammary gland tissues.

Main Results:

• Mex3c-mutant dams exhibited lactation failure, leading to pup starvation post-birth.
• Mammary glands contained milk in alveoli but showed deficiency in ducts.
• No deficiencies in prolactin or oxytocin were observed in mutant mice.
• Myoepithelial cells developed normally in the mammary glands of mutant mice.
• Mex3c expression was detected in the mammary gland epithelium.

Conclusions:

• Mex3c plays a crucial role in normal mammary gland function and lactation.
• Lactation defects in Mex3c mutants may stem from functional impairments within the mammary gland epithelium or myoepithelial cells.
• These findings highlight a novel function for Mex3c in maternal care and offspring viability.