Generation of myostatin edited horse embryos using CRISPR/Cas9 technology and somatic cell nuclear transfer.

The study focuses on using gene-editing technology, specifically CRISPR/Cas9, to knock out the myostatin gene in horse embryos. This gene negatively impacts muscle mass development. The research showed that higher concentrations of the gene-editing plasmids resulted in more efficient modification and that it’s possible to create horse embryos with the desired gene modifications.

Methodology

• The researchers used CRISPR/Cas9 technology to target and disrupt the myostatin gene (MSTN). This gene is known to limit muscle growth.
• Horse fetal fibroblasts (cells that produce collagen and other fibers and are crucial for healing wounds) were treated with two different gRNA/Cas9 plasmids, intending to target the first exon of the MSTN gene.
• Different concentrations (1, 2, or 5 µg) of these plasmids were used to determine the optimal amount needed for efficient gene editing.

Results

• It was observed that higher plasmid concentrations resulted in a more efficient gene edition.
• Specifically, the mutation efficiencies were 63.6% for gRNA1 and 96.2% for gRNA2.
• The researchers then selected three clonal cell lines, representing three different gene edition outcomes, to produce embryos via a process called somatic cell nuclear transfer, which is a cloning method.
• All embryos were successfully edited.

Verification & Analysis

• They analyzed both the MSTN editions and off-targets in the embryos to verify the edits made and evaluate the specificity of the method.
• The study concluded that CRISPR/Cas9 is a highly efficient and dose-dependent method for the effective modification of the horse’s genome.

Implications

• The successful application of this technology in horses suggests it could be adapted to create alleles that give sport horses an advantage.
• This also opens the door for developing precision breeding programs in other industries that could benefit from gene-edited embryos, such as livestock production or biomedical research, which could significantly advance these fields.