Animal Science Department, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, China.
Institute of Western Agriculture, the , Chinese Academy of Agricultural Sciences, Changji, China.
BMC Genomics. 2024 Nov 27;25(1):1146. doi: 10.1186/s12864-024-11038-y.
The yak (Bos grunniens) is essential to the livelihoods of Tibetan people on the Qinghai-Tibet Plateau; however, its growth and productivity are constrained by the region's harsh climate and high altitude. Yak skeletal muscle myoblasts, which have evolved to thrive under these challenging conditions, offer a valuable model for investigating muscle development. In this study, we performed transcriptome profiling of yak longissimus dorsi muscle at different growth stages, identifying a key long non-coding RNA, LncRNA-XR_314844 (Lnc-MEG8), with a potential role in muscle development.
We developed a novel technique to isolate high-quality yak myoblasts, enabling detailed analysis of Lnc-MEG8. Our results indicated that Lnc-MEG8's subcellular localization varies during muscle cell growth: it is found in both the nucleus and cytoplasm during proliferation but shifts mainly to the cytoplasm during differentiation. Functional experiments showed that Lnc-MEG8 promotes cell proliferation and inhibits differentiation, while its silencing had the opposite effect. Further analysis revealed that both Lnc-MEG8 and the gene RTL1 share miR-22-3p as a common target. Dual-luciferase assays confirmed miR-22-3p directly targets both Lnc-MEG8 and RTL1 mRNA. Co-transfection of Lnc-MEG8 and a miR-22-3p mimic restored RTL1 expression, highlighting Lnc-MEG8's regulatory role. Lnc-MEG8 also counteracts miR-22-3p's suppression of key muscle genes such as MyF5 and MyoG, facilitating myotube formation.
These findings demonstrate that the Lnc-MEG8-miR-22-3p-RTL1 axis plays a crucial role in yak muscle development, providing insights that could advance muscle tissue engineering and enhance yak meat quality.
牦牛（Bos grunniens）是青藏高原藏族人民生计的重要组成部分；然而，其生长和生产力受到该地区恶劣气候和高海拔的限制。牦牛骨骼肌成肌细胞在这些具有挑战性的条件下进化，为研究肌肉发育提供了有价值的模型。在这项研究中，我们对不同生长阶段牦牛背最长肌的转录组进行了分析，确定了一个关键的长非编码 RNA，LncRNA-XR_314844（Lnc-MEG8），它可能在肌肉发育中发挥作用。
我们开发了一种从牦牛中分离高质量成肌细胞的新技术，从而能够对 Lnc-MEG8 进行详细分析。结果表明，Lnc-MEG8 的亚细胞定位在肌肉细胞生长过程中发生变化：在增殖过程中，它存在于细胞核和细胞质中，但在分化过程中主要转移到细胞质中。功能实验表明，Lnc-MEG8 促进细胞增殖并抑制分化，而其沉默则产生相反的效果。进一步分析表明，Lnc-MEG8 和基因 RTL1 共享 miR-22-3p 作为共同靶标。双荧光素酶报告基因实验证实 miR-22-3p 直接靶向 Lnc-MEG8 和 RTL1 mRNA。Lnc-MEG8 和 miR-22-3p 模拟物的共转染恢复了 RTL1 的表达，突出了 Lnc-MEG8 的调节作用。Lnc-MEG8 还拮抗了 miR-22-3p 对关键肌肉基因如 MyF5 和 MyoG 的抑制作用，促进肌管形成。
这些发现表明，Lnc-MEG8-miR-22-3p-RTL1 轴在牦牛肌肉发育中起着关键作用，为肌肉组织工程的发展和提高牦牛肉质提供了新的见解。
