Regulatory mechanism of LncRNAs in gonadal differentiation of hermaphroditic fish, Monopterus albus

Abstract

Background Monopterusalbus is a hermaphroditic fish with sex reversal from ovaries to testes via the ovotestes in the process of gonadal development, but the molecular mechanism of the sex reversal was unknown. Methods We produced transcriptomes containing mRNAs and lncRNAs in the crucial stages of the gonad, including the ovary, ovotestis and testis. The expression of the crucial lncRNAs and their target genes was detected using qRT‒PCR and in situ hybridization. The methylation level and activity of the lncRNA promoter were analysed by applying bisulfite sequencing PCR and dual-luciferase reporter assays, respectively. Results This effort revealed that gonadal development was a dynamic expression change. Regulatory networks of lncRNAs and their target genes were constructed through integrated analysis of lncRNA and mRNA data. The expression and DNA methylation of the lncRNAs MSTRG.38036 and MSTRG.12998 and their target genes Psmβ8 and Ptk2β were detected in developing gonads and sex reversal gonads. The results showed that lncRNAs and their target genes exhibited consistent expression profiles and that the DNA methylation levels were negatively regulated lncRNA expression. Furthermore, we found that Ptk2β probably regulates cyp19a1 expression via the Ptk2β/EGFR/STAT3 pathway to reprogram sex differentiation. Conclusions This study provides novel insight from lncRNA to explore the potential molecular mechanism by which DNA methylation regulates lncRNA expression to facilitate target gene transcription to reprogram sex differentiation in M.albus, which will also enrich the sex differentiation mechanism of teleosts.

Expression and localization of HPG axis-related genes in Carassius auratus with different ploidy

“…In many cases, methylation of the promoter region of a gene leads to gene silencing or a reduction in expression levels, as methylation can prevent the binding of regulatory proteins such as transcription factors. Therefore, when the methylation level of a gene’s promoter region is reduced, it typically indicates that transcriptional barriers have been removed, making the gene more accessible to the transcriptional machinery and thereby resulting in increased levels of gene expression ( 41 ). Those changes are critical in many biological processes, such as regulating organisms ( 42 ), development ( 21 ) and response to environmental changes ( 43 ).…”