Hemizygous minipigs produced by random gene insertion and handmade cloning express the Alzheimer’s disease-causing dominant mutation APPsw

In an effort to develop a porcine model of Alzheimer’s disease we used handmade cloning to produce seven transgenic Go¨ttingen minipigs. The donor fibroblasts had been stably transfected with a plasmid cassette containing, as transgene, the cDNA of the neuronal variant of the human amyloid precursor protein gene with the Swedish mutation preceded by beta-globin sequences to induce splicing and a human PDGFbeta promoter fragment to drive transcription. Transgene insertion had occurred only at the GLIS3 locus where a single complete copy of the transgene was identified in intronic sequences in opposite direction. Similar and robust levels of the transgene transcript were detected in skin biopsies from all piglets and the sequence of full-length transcript was verified. Consistent with PDGFbeta promoter function, high levels of transgene expression, including high level of the corresponding protein, was observed in brain tissue and not in heart or liver tissues. A rough estimate predicts that accumulation of the Ab peptide in the brain may develop at the age of 1–2 years.