The British Roslin Institute, which created Dolly the sheep, succeeded in cloning a genetically modified experimental sheep in order to obtain a cure for ‘Batten’s disease’, a rare childhood genetic disease. The cloned sheep carry the mutated gene that causes Batten’s disease and was used to test the effectiveness of a treatment that has been proven in previous mice.
According to the Guardian on the 9th (local time), a research team at the Roslin Institute in the UK succeeded in cloning a defective amount of the gene ‘CLN1’ related to Batten’s disease using CRISPR gene editing technology.
Inherited from parents, Batten’s disease usually occurs in children aged 4 to 10 years. The most common symptom is vision loss, which occurs around the age of 10. Over time, cognitive decline, muscle stiffness, and sleep disturbance appear, and these complications often lead to death before the age of 20.
Batten’s disease is caused by abnormalities in the function of lysosomes, which are intracellular organs. Lysosomes are organs that break down or recycle waste products and fats that accumulate in cells. Among the genes, there are neuroceroid protein (CLN) genes that are responsible for the function of lysosomes. As these genes are mutated, the function of lysosomes is reduced. Batten’s disease is subdivided according to the type of mutation in the CLN gene.
Among the CLN genes, the research team focused on mutations in the CLN1 gene. This gene is specialized in recycling foreign substances accumulated in cells or aging cells.
The team created sheep with a defect in the CLN1 gene using a gene-scissing technique. The ovaries of sheep were extracted, modified to the CLN1 gene, and transplanted into experimental sheep to give birth to sheep with the genetic defect.
The resulting sheep was injected with an enzyme that the CLN1 gene must produce to break down foreign substances.
The sheep injected with the enzyme showed relief from the symptoms of the disease. The research team also found the appropriate injection amount and the most appropriate injection route for the enzyme through experiments.
In the previous mouse experiment, the injection of the enzyme was shown to improve the degradation function of the CLN1 gene.
Jonathan Cooper, a professor at Washington University of Medicine who participated in the study, said, “This experiment using sheep confirmed the safety that was not confirmed in a mouse experiment. I found a way to do it,” he said.
