Circular RNA screening identifies circMYLK4 as a regulator of fast/slow myofibers in porcine skeletal muscles

Haigang Cao,Xiaomin Zhou,Jie Wang,Jieming Liu,Xin’E Shi,Tianning Du,Yihao Liu,Xiao Li,Xiaoyu Zhang,Yuan Guo,Gongshe Yang

doi:10.1007/s00438-021-01835-5

Haigang Cao, Xiaomin Zhou + Show 9 more

Open Access

https://doi.org/10.1007/s00438-021-01835-5

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Abstract

The type of myofiber is related to the quality of meat. The slow oxidized myofiber helps to increase the tenderness and juiciness of muscle. Numerous studies have shown that circRNA plays a key role in skeletal muscle development. However, the role of circRNA in porcine skeletal myofiber types is unclear. In this study, we performed high-throughput RNA sequencing to study the differential expression of circRNA in the longissimus dorsi and the soleus muscle. A total of 40,757 circRNAs were identified, of which 181 were significantly different. Interestingly, some circRNAs were involved in metabolism pathways, AMPK, FoxO, and PI3K-Akt signaling pathways. Besides, we focused on a novel circRNA-circMYLK4. By injecting circMYLK4-AAV into piglets, we found that circMYLK4 significantly increased the mRNA and protein levels of the slow muscle marker genes. In summary, our study laid an essential foundation for further research of circRNA in myofiber type conversion and higher meat quality.

Highlights

Meat quality has been a major focus over the last decades because of both increasing living standards and population growth
Skeletal muscle fibers can be divided into fast muscle fibers and slow muscle fibers according to their morphological and functional characteristics (Bassel-Duby and Olson 2006)
Slow muscle fibers are characterized by high content of mitochondria, lipids and myoglobin and a small diameter, while fast muscle fibers have the opposite characteristics (Holloszy and Coyle 1984)

Summary

Introduction

Meat quality has been a major focus over the last decades because of both increasing living standards and population growth. As one of the dietary structures in our daily life, the quality of pork affects everyone’s health. Improving quality without decreasing meat production is a promising research direction for porcine breeding scientists. Pork quality is influenced by multiple factors, and a growing number of studies have shown that muscle fiber types are closely related to quality (Lefaucheur 2010). Compared to fast muscle fiber, slow muscle fiber improves meat quality by affecting meat pH (Ryu and Kim 2006; Choi et al 2007; Kim et al 2013b),. Increasing the proportion of slow muscle fibers is a powerful strategy to improve meat quality

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