Comparison of gene-trapping efficiency between retroviral and lentiviral vectors in mouse embryonic stem cells

► False-positive gene-trap events were frequently observed with the retroviral vector. ► Most of the retroviral integration sites were found in the 5′ untranslated region. ► The lentiviral vector integrated uniformly throughout transcriptional units. ► Lentiviral vectors can trap active genes more efficiently than retroviral vectors.