A Novel Circular RNA circSPEF2 Regulates Testis Development in Crucian Carp

Area of Science:

• Reproductive Biology
• Molecular Endocrinology
• Genomics

Background:

• Circular RNAs (circRNAs) show sex- and developmental stage-specific expression in fish gonads.
• Their roles in male reproductive development are largely unknown, particularly in crucian carp (Carassius auratus).

Purpose of the Study:

• To characterize the expression and function of circSPEF2 in crucian carp male reproductive development.
• To elucidate the regulatory mechanisms of circSPEF2 in gonadal maturation.

Main Methods:

• Expression analysis of circSPEF2 in testes during maturation.
• Overexpression and knockdown (siRNA) of circSPEF2 followed by transcriptome sequencing.
• Gene Ontology (GO) and KEGG pathway enrichment analyses.
• RNA pull-down assay coupled with mass spectrometry to identify binding proteins.

Main Results:

• circSPEF2 expression is elevated in mature testes and increases during gonadal maturation.
• circSPEF2 positively regulates cell maturation/differentiation genes (e.g., prdm1a) and suppresses proliferation/apoptosis genes (e.g., wnt8b).
• hnRNP A/B, SRSF2, and CFAP263 were identified as potential circSPEF2-binding proteins.

Conclusions:

• circSPEF2 is crucial for male gonadal development in fish.
• It acts via post-transcriptional regulation, influencing key developmental pathways.
• Provides novel insights into vertebrate male reproduction regulatory mechanisms.