Stem Cells & Development Unit, Institut Pasteur, 25 rue du Dr. Roux, 75015, Paris, France.
UMR CNRS 3738, Institut Pasteur, Paris, France.
Skelet Muscle. 2021 Feb 18;11(1):5. doi: 10.1186/s13395-021-00260-x.
Myogenin is a transcription factor that is expressed during terminal myoblast differentiation in embryonic development and adult muscle regeneration. Investigation of this cell state transition has been hampered by the lack of a sensitive reporter to dynamically track cells during differentiation.
Here, we report a knock-in mouse line expressing the tdTOMATO fluorescent protein from the endogenous Myogenin locus. Expression of tdTOMATO in Myog mice recapitulated endogenous Myogenin expression during embryonic muscle formation and adult regeneration and enabled the isolation of the MYOGENIN cell population. We also show that tdTOMATO fluorescence allows tracking of differentiating myoblasts in vitro and by intravital imaging in vivo. Lastly, we monitored by live imaging the cell division dynamics of differentiating myoblasts in vitro and showed that a fraction of the MYOGENIN population can undergo one round of cell division, albeit at a much lower frequency than MYOGENIN myoblasts.
We expect that this reporter mouse will be a valuable resource for researchers investigating skeletal muscle biology in developmental and adult contexts.
肌球蛋白重链是一种转录因子，在胚胎发育过程中的终末成肌细胞分化和成人肌肉再生中表达。由于缺乏一种敏感的报告基因来动态跟踪分化过程中的细胞，因此对这种细胞状态转变的研究受到了阻碍。
在这里，我们报告了一种在肌球蛋白重链基因座表达 tdTOMATO 荧光蛋白的敲入小鼠系。在 Myog 小鼠中，tdTOMATO 的表达再现了胚胎期肌肉形成和成人再生过程中内源性肌球蛋白重链的表达，并能够分离出 MYOGENIN 细胞群。我们还表明，tdTOMATO 荧光可用于体外跟踪分化的成肌细胞，并可在体内进行活体成像。最后，我们通过活体成像监测了体外分化成肌细胞的细胞分裂动力学，并表明 MYOGENIN 细胞群的一部分可以进行一轮细胞分裂，尽管频率远低于 MYOGENIN 成肌细胞。
我们预计，这种报告基因小鼠将成为研究发育和成年背景下骨骼肌生物学的研究人员的宝贵资源。
