A bacterial artificial chromosome (BAC), RPCI23-385H16, was used to isolate 144kb sequence containing the entire mouse Prox1 (prospero-related homeobox 1) gene. A 144kb portion of this BAC, containing only Prox1, was modified to include a red fluorescent protein, tdTomato, from the pClasper vector, between amino acid 5 and the Prox1 nuclear localization sequence. Line 12 contains 10 copies of the transgene. (J:182015)