Human elongation factor 1 alpha short form (EFS) promoter
Compact constitutive promoter created by truncating the human elongation factor 1 alpha (EF1A) promoter to remove its first intron and associated enhancer element. Retains stable, ubiquitous expression in a much smaller footprint than full-length EF1A, making it suited to size-constrained lentiviral and AAV vectors.
Origin: Truncated human EF1A promoter, intron and enhancer removed (engineered)
Characteristics
232 bp truncated derivative of the human EF1A promoter (Kim et al. 1990) lacking the first intron and its enhancer, which reduces the risk of the promoter trans-activating genes near a lentiviral integration site. In a side-by-side comparison against viral promoters (including CMV and MND) in primary human T cells and CD34+ hematopoietic stem/progenitor cells, EFS drives lower peak expression than the stronger viral promoters but maintains stable expression with less silencing over extended culture (Kao et al. 2014).
Applications: Used in lentiviral vectors for ex vivo gene modification of human CD34+ hematopoietic stem/progenitor cells and primary T cells for clinical gene-therapy applications; valued for its compact size in constructs with limited packaging capacity, such as AAV, and for lower genotoxicity risk than viral enhancer-containing promoters (Kao et al. 2014).
Limitations: Produces lower peak expression than strong viral promoters such as CMV or MND in primary human hematopoietic cells (Kao et al. 2014); removing the EF1A first intron also removes the intron-dependent expression-enhancing effect reported for full-length EF1A (Kim et al. 1990).
Used in
Sequence
References
- Kim et al. (1990). Use of the human elongation factor 1 alpha promoter as a versatile and efficient expression system. Gene - Kim 1990 EF1a Promoter