Comprehensive analysis of lncRNAs modified by m6A methylation in sheep skin.

Objective: N6-methyladenosine (m6A) is the most prevalent methylation of mRNA and plays crucial roles in various physiological processes, including pigmentation. Yet, the regulatory mechanisms, including long noncoding RNAs (lncRNAs) m6A methylation contributing to pigmentation in sheep skin remains unclear. The purpose of this study was to identify potential lncRNAs and the m6A methylation of lncRNAs associated with pigmentation.

Methods: RNA-seq and MeRIP-seq were performed to study the expression of lncRNAs and the m6A methylation of lncRNAs in black and white sheep skin. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the consistency with the RNA-seq and MeRIP-seq data.

Results: We identified 168 differentially expressed lncRNAs between the two sheep skin colors. The differentially expressed lncRNAs enriched in the pathway of ECM-receptor interaction, Rap1 signaling pathway, and Non-homologous end-joining may play essential roles in pigmentation. We identified 577 m6A peaks and 617 m6A peaks in black and white sheep skin, respectively, among which 20 m6A peaks showed significant differences. The enriched motif in sheep skin was "GGACU", which aligned with the consensus motif "RRACH" (R = A or G, H = A, C or U). Differently methylated lncRNAs enriched in PI3K-Akt signaling pathway and Wnt signaling pathway might participate in skin pigmentation. ENSOARG00020015168 was the unique lncRNA with high expression and methylation (Hyper-Up) in black sheep shin. A lncRNA-mRNA network was constructed, with pigmentation-related genes, such as PSEN2, CCND3, COL2A1, and ERCC3.

Conclusion: The m6A modifications of lncRNAs in black and white colored sheep skin were analyzed comprehensively, providing new candidates for the regulation of pigmentation.