The sheep is an economically important animal, and there is currently a major focus on improving its meat quality through breeding. There are variations in the growth regulation mechanisms of different sheep breeds, making fundamental research on skeletal muscle growth essential in understanding the regulation of (thus far) unknown genes. Skeletal muscle development is a complex biological process regulated by numerous genes and non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs). In this study, we used deep sequencing data from sheep longissimus dorsi (LD) muscles sampled at day 60, 90, and 120 of gestation, as well as at day 0 and 360 following birth, to identify and examine the lncRNA and miRNA temporal expression profiles that regulate sheep skeletal myogenesis. We stained LD muscles using histological sections to analyse the area and circumference of muscle fibers from the embryonic to postnatal development stages. Our results showed that embryonic skeletal muscle growth can be characterized by time. We obtained a total of 694 different lncRNAs and compared the differential expression between the E60 vs. E90, E90 vs. E120, E120 vs. D0, and D0 vs. D360 lncRNA and gene samples. Of the total 701 known sheep miRNAs we detected, the following showed a wide range of expression during the embryonic stage: miR-2387, miR-105, miR-767, miR-432, and miR-433. We propose that the detected lncRNA expression was time-specific during the gestational and postnatal stages. GO and KEGG analyses of the genes targeted by different miRNAs and lncRNAs revealed that these significantly enriched processes and pathways were consistent with skeletal muscle development over time across all sampled stages. We found four visual lncRNA–gene regulatory networks that can be used to explore the function of lncRNAs in sheep and may be valuable in helping improve muscle growth. This study also describes the function of several lncRNAs that interact with miRNAs to regulate myogenic differentiation.

中文翻译：

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胎羊骨骼肌中动态和广泛的lncRNA和miRNA表达分析

绵羊是一种重要的经济动物，目前主要关注通过育种提高其肉质。不同绵羊品种的生长调节机制存在差异，因此骨骼肌生长的基础研究对于理解（迄今为止）未知基因的调节至关重要。骨骼肌发育是一个复杂的生物过程，受众多基因和非编码 RNA 调控，包括微 RNA (miRNA) 和长链非编码 RNA (lncRNA)。在本研究中，我们使用来自妊娠第 60、90 和 120 天以及出​​生后第 0 天和第 360 天采样的绵羊背最长肌 (LD) 肌肉的深度测序数据来识别和检查 lncRNA 和 miRNA 的时间表达调节绵羊骨骼肌生成的配置文件。我们使用组织切片对 LD 肌肉进行染色，以分析从胚胎到出生后发育阶段的肌肉纤维的面积和周长。我们的结果表明，胚胎骨骼肌的生长可以用时间来表征。我们总共获得了 694 个不同的 lncRNA，并比较了 E60 与 E90、E90 与 E120、E120 与 D0、D0 与 D360 lncRNA 和基因样本之间的差异表达。在我们检测到的总共 701 种已知绵羊 miRNA 中，以下显示在胚胎阶段的广泛表达：miR-2387、miR-105、miR-767、miR-432 和 miR-433。我们建议检测到的 lncRNA 表达在妊娠和产后阶段具有时间特异性。对不同 miRNA 和 lncRNA 靶向基因的 GO 和 KEGG 分析表明，这些显着富集的过程和途径与所有采样阶段随时间推移的骨骼肌发育一致。我们发现了四种视觉 lncRNA 基因调控网络，可用于探索 lncRNA 在绵羊中的功能，并且可能有助于改善肌肉生长。该研究还描述了几种与 miRNA 相互作用以调节肌源性分化的 lncRNA 的功能。