1. A MSTNDel73C mutation with FGF5 knockout sheep by CRISPR/Cas9 promotes skeletal muscle myofiber hyperplasia
- Author
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Ming-Ming Chen, Yue Zhao, Kun Yu, Xue-Ling Xu, Xiao-Sheng Zhang, Jin-Long Zhang, Su-Jun Wu, Zhi-Mei Liu, Yi-Ming Yuan, Xiao-Fei Guo, Shi-Yu Qi, Guang Yi, Shu-Qi Wang, Huang-Xiang Li, Ao-Wu Wu, Guo-Shi Liu, Shou-Long Deng, Hong-Bing Han, Feng-Hua Lv, Di Lian, and Zheng-Xing Lian
- Subjects
MSTN ,FGF5 ,dual-gene biallelic mutation ,FOSL1 ,myogenesis ,Medicine ,Science ,Biology (General) ,QH301-705.5 - Abstract
Mutations in the well-known Myostatin (MSTN) produce a ‘double-muscle’ phenotype, which makes it commercially invaluable for improving livestock meat production and providing high-quality protein for humans. However, mutations at different loci of the MSTN often produce a variety of different phenotypes. In the current study, we increased the delivery ratio of Cas9 mRNA to sgRNA from the traditional 1:2 to 1:10, which improves the efficiency of the homozygous mutation of biallelic gene. Here, a MSTNDel73C mutation with FGF5 knockout sheep, in which the MSTN and FGF5 dual-gene biallelic homozygous mutations were produced via the deletion of 3-base pairs of AGC in the third exon of MSTN, resulting in cysteine-depleted at amino acid position 73, and the FGF5 double allele mutation led to inactivation of FGF5 gene. The MSTNDel73C mutation with FGF5 knockout sheep highlights a dominant ‘double-muscle’ phenotype, which can be stably inherited. Both F0 and F1 generation mutants highlight the excellent trait of high-yield meat with a smaller cross-sectional area and higher number of muscle fibers per unit area. Mechanistically, the MSTNDel73C mutation with FGF5 knockout mediated the activation of FOSL1 via the MEK-ERK-FOSL1 axis. The activated FOSL1 promotes skeletal muscle satellite cell proliferation and inhibits myogenic differentiation by inhibiting the expression of MyoD1, and resulting in smaller myotubes. In addition, activated ERK1/2 may inhibit the secondary fusion of myotubes by Ca2+-dependent CaMKII activation pathway, leading to myoblasts fusion to form smaller myotubes.
- Published
- 2024
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