Vitellogenin2: spermatozoon specificity and immunoprotection in mud crabs

Area of Science:

• Reproductive Biology
• Immunology
• Crustacean Science

Background:

• Vitellogenin (Vg) is typically known as a female-specific yolk precursor protein.
• Previous research identified Vg1 (vtg1) in female mud crabs (Scylla paramamosain).
• Vg has been observed in males under specific experimental conditions.

Purpose of the Study:

• To investigate the presence and function of a novel vitellogenin isoform (vtg2) in male mud crab testes.
• To determine the localization and potential immune role of vtg2/Vn in the male reproductive system.

Main Methods:

• Sequence analysis to identify Vg isoforms.
• Polymerase Chain Reaction (PCR) and in situ hybridization to determine vtg2 localization.
• Immune challenge experiments using lipopolysaccharide (LPS) and lipoteichoic acid (LTA) to assess vtg2 expression.

Main Results:

• A distinct Vg isoform, vtg2, was identified in male mud crab testis under normal physiological conditions.
• vtg2/Vn was localized specifically in testicular spermatozoa and seminal vesicles.
• Expression of vtg2/Vn was significantly upregulated in the testis following LPS and LTA injection at both transcriptional and translational levels.

Conclusions:

• Vitellogenin 2 (vtg2) is a novel immune-relevant molecule in the male reproductive system of mud crabs.
• vtg2/Vn likely plays a role in immunoprotection during spermatozoon maturation.
• This finding opens new avenues for understanding the diverse roles of Vg in male reproductive immunity.