Difference between EF-1 alpha and the CMV promoter

Human elongation factor-1 alpha (EF-1 alpha) is a constitutive promoter of human origin that can be used to drive ectopic gene expression in various in vitro and in vivo contexts. EF-1 alpha is often useful in conditions where other promoters (such as CMV) have diminished activity or have been silenced (as in embryonic stem cells).

Teschendorf C reported that stable HT-29 (colon carcinoma) clones with > 97% of all cells homogeneously expressing GFP were generated with the EF-1 alpha promoter. In contrast in clones carrying the CMV promoter, only up to 60% of the cells were GFP-positive with expression levels varying widely between cells.

Superinfection with wild-type adenovirus induced GFP expression in more than 90% of the cells indicating that the CMV promoter was silenced. In vivo the tumors carrying the EF-1 alpha promoter were homogeneously GFP-positive, whereas the CMV promoter gave rise to a scattered pattern of GFP expression.

Reference: Teschendorf C, Warrington KH Jr, Siemann DW, Muzyczka N. Comparison of the EF-1 alpha and the CMV promoter for engineering stable tumor cell lines using recombinant adeno-associated virus. Anticancer Res. 2002 Nov-Dec;22(6A):3325-30. PMID: 12530082.