To determine whether Arl2 KD affects the proliferation and differentiation of mNPCs during mouse cortical development, we silenced endogenous Arl2 expression in the primary culture of mNPCs in vitro by lentivirus (pPurGreen) infection in 48-h culture and pulse-labelled with 5-ethynyl-2′-deoxyuridine (EdU) for 3 h before harvesting the cells. The gene discussed is ARL2; the disease is infection.