# Characterization of RNA Editing in Oxidative and Glycolytic Skeletal Muscles of Yak

## TL;DR

This study maps RNA editing in yak muscles and finds differences between oxidative and glycolytic fibers, linking RNA editing to muscle fiber type regulation.

## Contribution

The study provides the first comprehensive RNA editing landscape in yak muscle and identifies fiber-type-specific editing patterns.

## Key findings

- 17,713 RNA editing sites were identified, with 2535 showing significant differences between muscle types.
- Differentially edited genes were enriched in pathways like MAPK and calcium signaling, linked to muscle fiber regulation.
- RNA editing may influence miRNA binding and protein function, suggesting a role in muscle fiber type transformation.

## Abstract

To investigate the role of RNA editing in yak muscle fiber type transformation, this study systematically analyzed RNA editing patterns in yak oxidative muscle fibers and glycolytic muscle fibers tissues by integrating transcriptomic and genomic sequencing data. A total of 17,713 high-confidence RNA editing sites were identified, with 2535 showing significant differences between the two muscle types. Functional enrichment analysis revealed that these differentially edited genes were mainly involved in pathways associated with muscle fiber type regulation, such as the MAPK signaling pathway and calcium signaling pathway. This study provides new molecular evidence for understanding the potential role of RNA editing in the physiological regulation of yak muscle.

Fast-twitch and slow-twitch muscle fibers not only differ in metabolic characteristics and physiological functions but also significantly influence the texture of livestock meat. RNA editing represents an important post-transcriptional regulatory process that can influence both gene expression and the resulting protein function. However, studies on RNA editing events in yak muscle remain limited. This study systematically identified RNA editing events in yak biceps femoris (BF, n = 3) and obliquus externus abdominis (OEA, n = 3) using transcriptomic data, discovering 17,713 unique editing sites, most located in non-coding regions. Within coding regions, 3350 sites were detected, with 1195 resulting in non-synonymous amino acid substitutions. Further analysis revealed that 785 sites potentially affected miRNA binding sites, suggesting RNA editing may participate in miRNA-mediated gene regulation. Tukey’s post hoc test (p < 0.05) identified 242 sites (involving 170 genes) with significantly different editing levels between BF and OEA. KEGG pathway analysis indicated that genes with differential RNA editing were predominantly associated with pathways involved in muscle fiber type transitions, including the MAPK and calcium signaling pathways. Collectively, this study maps the RNA editing landscape in yak muscle tissue and identifies distinct, fiber-type-specific RNA editing patterns between oxidative and glycolytic muscle fibers, including differences in editing levels and site distributions, supporting a potential association between RNA editing and muscle fiber type transformation.