Comprehensive identification and characterization of ribosomal protein genes in the Pacific oyster (Crassostrea gigas): Potential roles in reproduction and development

Ribosomal proteins (Rps) play important roles in ribosomal assembly, protein synthesis, and various extraribosomal functions. In this study, we identified and analyzed 75 ribosomal protein genes (CgRp) from the Pacific oyster (Crassostrea gigas), including 32 small subunit ribosomal proteins and 43 large subunit ribosomal proteins. These genes were categorized into six subgroups and 44 subfamilies, with structural analysis revealing variability in gene exon number and untranslated regions. Transcriptomic profiling revealed tissue-specific expression patterns, with three CgRp genes (CgRL1P1, CgRPS21 and CgRPS18) enriched in gonadal tissue. Notably, 27 CgRp genes in males exhibited high expression during the resting and early development stages, followed by a downregulation trend during maturation. A total of 72 CgRps peaked in expression during the spat stage, highlighting their involvement in critical developmental processes such as tissue differentiation and organogenesis. qPCR validation confirmed the accuracy of the transcriptomic findings, particularly for genes with distinct expression profiles in male and female gonads. This study provides novel insights into the role of Rps in reproductive and developmental processes in C. gigas, contributing to the understanding of their functional diversity and potential applications in oyster breeding.