Xie Shu-Juan, Lei Hang, Yang Bing, Diao Li-Ting, Liao Jian-You, He Jie-Hua, Tao Shuang, Hu Yan-Xia, Hou Ya-Rui, Sun Yu-Jia, Peng Yan-Wen, Zhang Qi, Xiao Zhen-Dong
Vaccine Research Institute of Sun Yat-sen University, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Biotherapy Center, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Front Cell Dev Biol. 2021 Oct 1;9:744171. doi: 10.3389/fcell.2021.744171. eCollection 2021.
N-methyladenosine (mA) RNA methylation has emerged as an important factor in various biological processes by regulating gene expression. However, the dynamic profile, function and underlying molecular mechanism of mA modification during skeletal myogenesis remain elusive. Here, we report that members of the mA core methyltransferase complex, METTL3 and METTL14, are downregulated during skeletal muscle development. Overexpression of either METTL3 or METTL14 dramatically blocks myotubes formation. Correspondingly, knockdown of METTL3 or METTL14 accelerates the differentiation of skeletal muscle cells. Genome-wide transcriptome analysis suggests ERK/MAPK is the downstream signaling pathway that is regulated to the greatest extent by METTL3/METTL14. Indeed, METTL3/METTL14 expression facilitates ERK/MAPK signaling. Via MeRIP-seq, we found that MNK2, a critical regulator of ERK/MAPK signaling, is mA modified and is a direct target of METTL3/METTL14. We further revealed that YTHDF1 is a potential reader of mA on MNK2, regulating MNK2 protein levels without affecting mRNA levels. Furthermore, we discovered that METTL3/14-MNK2 axis was up-regulated notably after acute skeletal muscle injury. Collectively, our studies revealed that the mA writers METTL3/METTL14 and the mA reader YTHDF1 orchestrate MNK2 expression posttranscriptionally and thus control ERK signaling, which is required for the maintenance of muscle myogenesis and may contribute to regeneration.
N-甲基腺苷（mA）RNA甲基化已成为通过调节基因表达参与各种生物学过程的重要因素。然而，在骨骼肌生成过程中，mA修饰的动态变化、功能及潜在分子机制仍不清楚。在此，我们报道mA核心甲基转移酶复合物成员METTL3和METTL14在骨骼肌发育过程中表达下调。过表达METTL3或METTL14均可显著阻碍肌管形成。相应地，敲低METTL3或METTL14可加速骨骼肌细胞分化。全基因组转录组分析表明，ERK/MAPK是受METTL3/METTL14调控程度最大的下游信号通路。事实上，METTL3/METTL14的表达促进ERK/MAPK信号传导。通过MeRIP-seq，我们发现ERK/MAPK信号的关键调节因子MNK2发生了mA修饰，并且是METTL3/METTL14的直接靶点。我们进一步揭示YTHDF1是MNK2上mA的潜在识别蛋白，可调节MNK2蛋白水平而不影响mRNA水平。此外，我们发现急性骨骼肌损伤后，METTL3/14-MNK2轴显著上调。总体而言，我们的研究表明，mA书写蛋白METTL3/METTL14和mA识别蛋白YTHDF1在转录后协调MNK2的表达，从而控制ERK信号传导，这是维持肌肉生成所必需的，并且可能有助于肌肉再生。
