Genome-Wide Gene Expression Profiles in Testicular Tissues of Pig Breeds Differing in Precocious Puberty

MicroRNAs (miRNAs) are short non-coding RNA molecules that target mRNAs for translational repression or degradation, and they also have been reported to be involved in mammalian spermatogenesis. However, little knowledge has been revealed on miRNAs and genes differentially expressed in pig breeds differing in precocious puberty. Illumina GAIIx sequencing technology was employed to profile miRNAs and mRNA in Luchuan pigs and Large White at sexually immature and mature testes. A total of 22,289 expressed genes were detected for these two breeds. Within-breed comparison, there were 9,012 differentially expressed genes (DEGs) between Large White at two stages, and 7,336 DEGs in Luchuan pigs. Inter-breed comparison, there were 1,375 DEGs in Luchuan and Large White at mature testes, and 1,435 DEGs at immature testes. It indicates that gene expression differences during testis maturation processing could mostly explain for difference between breeds. By miRNA profiling comparison, within breed, there were 54 differentially expressed miRNAs (DEMs) in Large White at sexual maturity, and 43 DEMs in Luchuan pigs. Inter-breed comparison showed, there were only three DEMs in Luchuan and Large White at mature testes, and only one DEM before sexual maturity. MiRNA expression differences of two breeds were significantly less than those of sexually developmental stages. In addition, a few of miRNA target genes involved in spermatogenesis and cell adhesion were predicted by DAVID. The findings from the study indicated specific miRNAs expression has an important regulatory role during the processing of developing testicular maturation, as well as differences between pig breeds with sexual maturation differential.