PrP.XhoI vector (also known as pPrPpE1/E2,3sal [15]) with the tetracycline-responsive promoter of pTetSplice (Life Technologies, Rockville, Maryland, United States), and then ligating mouse APP with a humanized Aβ domain (mo/huAPP695) cDNA into the new vector. We began by cloning the tetracycline-responsive promoter