Studies On Tissue And Spatio-temporal Expression Of Porcine CircRNA

Circular RNA(circRNA)is a new type of RNA with a closed circular structure.It is formed by reverse splicing of mRNA precursors.CircRNA is widely identified in pigs and other mammals.CircRNA generally regulates target genes indirectly by sponging miRNAs,and some circRNAs have a potential to code protein.We collected 813 independent and published RNA-seq data from pigs and 19 types of tissues(organs)were involved.In this study,a total of 168,292 circular RNAs were identified.It is found that circRNA expression was tissue-specifically expressed.There are more circRNA specifically expressed in testis and spleen than in other tissues.For these tissue-specifically expressed circRNA,we made GO enrichment analysis.Furthermore,to study the biological role of circRNA on meat production,we performed 81 RNA-seq on Landrace,Tongcheng and ChangTong(Landrace×Tongcheng)hybrid pigs(27 developmental stages for each pig breed).we identified many developmental stage-specific expressed circRNAs,and these circRNAs were involved in skeletal muscle development.We also found that circRNA expression abundance accumulated along muscle development,that is,the overall expression of circRNA was increased in the later development stages.In addition,we have also found that pig breed specifically expressed circRNA.These specific expressed circRNA may be related to the post-regulation of muscle development in different pig breeds.Overall,in this study,we investigated circRNA expression among 19 porcine tissues and 27 developmental stages in longissimus dorsi muscle,we also identified tissue-and temporal-spatially expressed circRNA,and we also improved porcine circRNA database.These results will provide a reference for screening circRNA in porcine biological function research.