NCAPG Dynamically Coordinates the Myogenesis of Fetal Bovine Tissue by Adjusting Chromatin Accessibility.

NCAPG is a subunit of condensin I that plays a crucial role in chromatin condensation during mitosis. NCAPG has been demonstrated to be associated with farm animal growth traits. However, its role in regulating myoblast differentiation is still unclear. We used myoblasts derived from fetal bovine tissue as an in vitro model and found that NCAPG was expressed during myogenic differentiation in the cytoplasm and nucleus. Silencing NCAPG prolonged the mitosis and impaired the differentiation due to increased myoblast apoptosis. After 1.5 days of differentiation, silencing NCAPG enhanced muscle-specific gene expression. An assay for transposase-accessible chromatin- high throughput sequencing (ATAC-seq) revealed that silencing NCAPG altered chromatin accessibility to activating protein 1 (AP-1) and its subunits. Knocking down the expression of the AP-1 subunits fos-related antigen 2 (FOSL2) or junB proto-oncogene (JUNB) enhanced part of the muscle-specific gene expression. In conclusion, our data provide valuable evidence about NCAPG's function in myogenesis, as well as its potential role in gene expression.

A Novel Mechanism of bta-miR-210 in Bovine Early Intramuscular Adipogenesis.

Intramuscular fat (IMF) is one of the major factors determining beef quality. IMF formation is influenced by multiple conditions including genetic background, age and nutrition. In our previous investigation, bta-miR-210 was found to be increased during adipogenesis using miRNA-seq. In this study, we validated the upregulation of bta-miR-210 in platelet-derived growth factor receptor α positive (PDGFRα+) progenitor cells during adipogenic differentiation in vitro. To investigate its role in adipogenesis, bta-miR-210 mimics were introduced into progenitor cells, which resulted in enhanced intracellular lipid accumulation. Accordingly, the expression of adipocyte-specific genes significantly increased in the bta-miR-210 mimic group compared to that in the negative control group (p < 0.01). Dual-luciferase reporter assays revealed that WISP2 is a target of bta-miR-210. WISP2 knockdown enhanced adipogenesis. In conclusion, bta-miR-210 positively regulates the adipogenesis of PDGFRα+ cells derived from bovine fetal muscle by targeting WISP2.

bta-miR-23a Regulates the Myogenic Differentiation of Fetal Bovine Skeletal Muscle-Derived Progenitor Cells by Targeting MDFIC Gene.

miR-23a, a member of the miR-23a/24-2/27a cluster, has been demonstrated to play pivotal roles in many cellular activities. However, the mechanisms of how bta-miR-23a controls the myogenic differentiation (MD) of PDGFRα- bovine progenitor cells (bPCs) remain poorly understood. In the present work, bta-miR-23a expression was increased during the MD of PDGFRα- bPCs. Moreover, bta-miR-23a overexpression significantly promoted the MD of PDGFRα- bPCs. Luciferase reporter assays showed that the 3'-UTR region of MDFIC (MyoD family inhibitor domain containing) could be a promising target of bta-miR-23a, which resulted in its post-transcriptional down-regulation. Additionally, the knockdown of MDFIC by siRNA facilitated the MD of PDGFRα- bPCs, while the overexpression of MDFIC inhibited the activating effect of bta-miR-23a during MD. Of note, MDFIC might function through the interaction between MyoG transcription factor and MEF2C promoter. This study reveals that bta-miR-23a can promote the MD of PDGFRα- bPCs through post-transcriptional downregulation of MDFIC.

Bta-miR-24-3p Controls the Myogenic Differentiation and Proliferation of Fetal, Bovine, Skeletal Muscle-Derived Progenitor Cells by Targeting ACVR1B.

MicroRNAs modulate a variety of cellular events, including skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is poorly understood. In this study, we report that bta-miR-24-3p promotes the myogenic differentiation of fetal bovine PDGFRα- progenitor cells. The expression of bta-miR-24-3p increased during myogenic differentiation. Overexpression of bta-miR-24-3p significantly promoted myogenic differentiation, but inhibited proliferation. A dual-luciferase assay identified ACVR1B as a direct target of bta-miR-24-3p. Similarly, knocking down ACVR1B by RNA interference also significantly inhibited proliferation and promoted the differentiation of bovine PDGFRα- progenitor cells. Thus, our study provides a mechanism in which bta-miR-24-3p regulates myogenesis by inhibiting ACVR1B expression.

bta-miR-23a involves in adipogenesis of progenitor cells derived from fetal bovine skeletal muscle.

Intramuscular fat deposition or marbling is essential for high quality beef. The molecular mechanism of adipogenesis in skeletal muscle remains largely unknown. In this study, we isolated Platelet-derived growth factor receptor α (PDGFRα) positive progenitor cells from fetal bovine skeletal muscle and induced into adipocytes. Using miRNAome sequencing, we revealed that bta-miR-23a was an adipogenic miRNA mediating bovine adipogenesis in skeletal muscle. The expression of bta-miR-23a was down-regulated during differentiation of PDGFRα+ progenitor cells. Forced expression of bta-miR-23a mimics reduced lipid accumulation and inhibited the key adipogenic transcription factor peroxisome proliferative activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha (C/EBPα). Whereas down-regulation of bta-miR-23a by its inhibitors increased lipid accumulation and expression of C/EBPα, PPARγ and fatty acid-binding protein 4 (FABP4). Target prediction analysis revealed that ZNF423 was a potential target of bta-miR-23a. Dual-luciferase reporter assay revealed that bta-miR-23a directly targeted the 3'-UTR of ZNF423. Together, our data showed that bta-miR-23a orchestrates early intramuscular adipogeneic commitment as an anti-adipogenic regulator which acts by targeting ZNF423.