The Tyro-IRES-sd-loxP-FUGW lentiviral transgene (LV2187) was designed with a mouse tyrosinase minigene (Tyro) followed by an IRES::3xATG::splice-donor::loxP sequence in the FUGW self-inactivating HIV-based lentiviral vector backbone. The Tyro-IRES-sd-loxP replaced the ubiquitin-c promoter, EGFP, and WPRE sequences originally found in the FUGW lentiviral vector. The Tyro minigene is composed of the mouse Tyr enhancer region (623 bp), promoter region (657 bp), and 1566 bp cDNA sequence (including the stop codon); all in antisense orientation relative to the FUGW backbone. The Tyro minigene is followed by an internal ribosome entry site (IRES) ending with ATGs in all three reading frames (3xATG), an artificial splice donor sequence, and a loxP site in this construct. In line 2395D-2a, the lentiviral transgene inserted into exon 14 (NCBI37/mm9; 5'-124,769,406(-)).