Each vial contains a stable population of 1 million A549 cells expressing the NucLight Red fluorescent protein restricted to the nucleus. Parental A549 cells were purchased from ATCC (Cat# CCL-185). A549 cells were transduced with the IncuCyte® NucLight Red Lentivirus (Cat# 4476; EF1α, puromycin) at an MOI of 3 (TU/cell) in the presence of 8 µg/ml polybrene following the standard Essen protocol. This resulted in ≥70% transduction efficiency. 48 hours post infection, the complete population of cells were grown for 3-5 days in complete growth media containing 1 µg/ml Puromycin to select for cells expressing NucLight Red. NucLight Red expressing cells are maintained in complete media containing 0.5 µg/ml Puromycin. Following selection, a panel of validation assays designed to evaluate the effects of nuclear label expression on functional cell biology was completed. These assays include comparisons of cell morphology, growth/proliferation, migration, and cytotoxicity between stable populations and the parent populations from which they were derived. In addition, all cells in our NucLight Red catalog has been certified mycoplasma free by ATCC and our stable populations have been unambiguously authenticated using ATCC’s Short Tandem Repeat (STR) profiling.