Strand-specific RNA sequencing in pig testes identifies developmentally regulated genes and circular RNAs

Abstract

Testicular development and spermatogenesis are strictly regulated with the complex interactions between several cell types in testis. However, the limited availability of genomic and molecular information limits our understanding of this complex physiological process. In this study, we characterized the transcriptome between immature (30-day-old) and mature (180-day-old) pig testes using RNA-seq technology. 24,469 known coding gene transcripts corresponding to 20,566 genes were mapped in these two developmental stages, 3,328 genes were differentially expressed, and numerous novel transcripts and alternative splicing events were also identified. Ten differentially expressed genes were validated by measuring the relative expression using real-time quantitative polymerase chain reaction (PCR). 125 Gene Ontology (GO) terms were significantly enriched, and most of them involved in GO terms related to male reproduction, testicular development, and spermatogenesis. In addition, this study also represented the prediction of 10,000 circRNAs, as well as the validation of six pig circRNAs using Find_cric algorithm. Our study substantially expanded our knowledge about the transcriptomic profile of immature and mature pig testes, and provided a useful resource to study the mechanisms of pig testis development and spermatogenesis at the molecular level.