pLL-EF1a-Luciferase-T2A-Puro Lenti-Labeler™ Lentivector Plasmid & Pre-packaged Virus. SBI’s family of Lenti-Labeler™ constructs facilitate a wide range of studies—including cell tracking, high-throughput assays, and more—by enabling efficient and reliable. SBI’s family of Lenti-Labeler™ constructs facilitate a wide range of studies—including cell tracking, high-throughput assays, and more—by enabling efficient and reliable labeling of your cells. The pLL-EF1α-Luciferase-T2A-Puro Lenti-Labeler™ construct expresses luciferase from the EF1α promoter, which delivers moderate expression in most cell types (including primary and stem cells), and co-expresses the puromycin resistance gene for selection in vitro prior to in vivo use.