Enhanced muscle growth via DNA methylation editing of mstnb exon in zebrafish

Muscle tissue constitutes the primary protein reservoir in fish and serves as the key energy source. Myostatin ( mstn ) functions as a negative regulator of muscle growth. At the same time, reduced mstn expression accelerates muscle hypertrophy. In this study, we applied CRISPR/dCas9-mediated DNA methylation editing to target the second exon of mstnb in zebrafish, thereby altering DNA methylation levels without modifying the DNA sequence. Results demonstrated that elevated mstnb methylation significantly suppressed mstnb mRNA expression. After 140 days of growth, the adult zebrafish displayed significantly greater body length and weight compared with controls. This work illustrates an innovative application of epigenetic editing technology in aquaculture breeding. By precisely modulating the expression patterns of key economic trait genes while maintaining genomic DNA integrity, this approach offers potential practical guidance for understanding the spatiotemporal expression and regulatory mechanisms of muscle-related functional genes in fish, as well as elucidating the roles of associated regulatory factors. Overall, it offers a promising avenue for accelerating growth in farmed fish and boosting aquaculture productivity.