Telomerase reverse transcriptase (TERT, or hTERT in human) is a catalytic subunit of the enzyme telomerase, Ectopic expression of telomerase in telomerase-silent cells is sufficient to overcome senescence and to extend cellular lifespan, and has been used for cell immortalization. This lentivirus expresses hTERT under the control of CAG promoter with puromycin as a selection marker.