Using both plasmid and adeno-associated virus (AAV) donor vectors, our results demonstrate that ataxia telangiectasia and Rad3-related kinase (ATR) activity is essential for knock-in regardless of the donor type, whereas ataxia telangiectasia mutated (ATM) inhibition exhibits a donor-dependent role. The gene discussed is ATM; the disease is Ataxia-telangiectasia.