Systematic comparison of constitutive promoters and the doxycycline-inducible promoter

Abstract

Constitutive promoters are used routinely to drive ectopic gene expression. Here, we carried out a systematic comparison of eight commonly used constitutive promoters (SV40, CMV, UBC, EF1A, PGK and CAGG for mammalian systems, and COPIA and ACT5C for Drosophila systems). We also included in the comparison the TRE promoter, which can be activated by the rtTA transcriptional activator in a doxycycline-inducible manner. To make our findings representative, we conducted the comparison in a variety of cell types derived fromseveral species.We found that these promoters vary considerably fromone another in their strength.Most promoters have fairly consistent strengths across different cell types, but the CMV promoter can vary considerably fromcell type to cell type. Atmaximal induction, the TRE promoter is comparable to a strong constitutive promoter. These results should facilitate more rational choices of promoters in ectopic gene expression studies. © 2010 Qin et al.