Design and transfection of CRISPR/Cas9 constructs for the myostatin gene in Labeo rohita muscle cells.

Myostatin (mstn) is a negative regulator of skeletal muscle growth and is considered as an important target for enhancing aquaculture production. The present study aimed to design and validate single-guide RNAs (sgRNAs) and CRISPR/Cas9 constructs for exon 1 of the mstnb gene in Labeo rohita, and to evaluate their transfection efficiency in the L. rohita dorsal muscle (LRDM) cell line at the 10th, 20th, and 30th passages. sgRNAs were designed and cloned into the pSpCas9(BB)-2A-GFP (PX458) vector using BbsI restriction digestion and ligation. Successful insertion and correct orientation of the sgRNAs were confirmed through Sanger sequencing. LRDM cells were revived and maintained in L-15 medium supplemented with 10% fetal bovine serum. Transfection was performed at the 10th, 20th, and 30th passages. Distinct GFP-positive cells were observed at all passages for both sgRNA constructs, indicating the ability of the developed cell line to successfully express the constructs across different passages. The study successfully established CRISPR/Cas9 plasmid constructs for the mstnb gene in L. rohita and demonstrated their transfection in LRDM cell line across multiple passages. These findings provide a basis for future studies on genome editing approaches using CRISPR/Cas9 constructs in fish muscle cell lines and highlight the potential application of CRISPR/Cas9 technology for genetic engineering applications in fish muscle cells.