Speaking of mammals (see the end of my previous entry), not even rats and mice always cut it when it comes to providing good models of human disease. Take, for example, cystic fibrosis. There are a couple of mouse models of the disease (we have published at least one of them), but the community does not seem to be satisfied with them. It is therefore great to see a pair of papers in the JCI reporting on two new attempts at generating the ideal model of cystic fibrosis.
The two of studies are very similar. In the first one, Xingshen Sun and colleagues report the first description of genetically engineered ferrets. They started by targetting the CFTR gene (the gene affected in the disease) in fibroblasts using an adeno-associated viral (AAV) construct, and then used a nuclear transfer protocol to obtain cloned ferrets heterozygous for the CFTR mutation. In the second one, Christopher Rogers and colleagues employed a similar strategy in pigs to obtain heterozygous piglets carrying the CFTR mutation.
The next steps will be to establish how much these models truly recapitulate human disease, and then use them to learn new biology about the disease and/or for preclinical drug-discovery work.
The figures, taken from the papers, show the cloned CFTR ferrets and a non-cloned albino at different ages, and the first CFTR heterozygous pig at one day of age.