Identification of  LncRNAs/circRNAs  associated with testicular development and spermatogenesis in black goat
Establishment and maintenance of spermatogenesis need a complex process and vast regulatory network. There is growing evidence reveals that long noncoding RNAs (lncRNA) plays important role in regulating testicular development and spermatogenesis in a stage-specific way. We here report the identification of lncRNA LOC108635509 as key lncRNA regulator in black goat spermatogenesis. In the current study, we screened the transcriptomes (lncRNA and mRNA) of testicular from Guangxi black goats before puberty (3 days old, D3; 30 days old, D30), puberty (90 days old, D90) and postpuberty (180 days old, D180), and found there were 1211, 12180, 834 differential lncRNAs and 1196, 8838,269 differential mRNAs at the ages of D30 vs D3, D90 vs D30, and D180 vs D90. The expression pattern of differentially expressed (DE) lncRNAs indicated that D90 was a key node of lncRNAs participated in the regulation of testicular development and spermatogenesis in black goat. The of GO and KEGG analyses identified that DE lncRNAs and their target genes regulated spermatogenesis through MAPK, Ras, and PI3K-Akt signal pathways. Using cis- and trans-acting, 39 DE lncRNA-targeted genes were found to be enriched for male reproduction. Of these, LOC108635509, which specific expressed in testis and upregulated the expression levels at D90, was found participated in the regulation of testicular development through promoting the proliferation of SCs. Overall, this study provides new insight into the regulatory mechanisms that support spermatogenesis and testicular development in black goats. Overall design: To investigate the roles of mRNAs, lncRNAs andcircRNAs in the regulation of black goat testicular development, twelve cDNA libraries of neonatal (D3-1, D3-2, D3-3), prepuberty (D30-1, D30-2, D30-3), puberty (D90-1, D90-2, D90-3) and postpuberty (D180-1, D180-2, D180-3) testes were constructed. Then performed comparative gene expression profiling analysis of RNA-seq data and identified key DE lncRNAs. Finally,  the location and function of  key lncRNAs in Sertoli cells  were confirmed.