Enhanced smooth muscle 22 alpha (enSM22α) promoter

Characteristics

Adding the rabbit SMMHC enhancer upstream of the SM22alpha promoter core substantially increases reporter gene expression relative to the SM22alpha promoter alone, while preserving smooth-muscle restriction - in vivo, reporter activity is confined to arterial smooth muscle with no detectable expression at remote, non-vascular sites. Retains the postnatal restriction to conductive arterial smooth muscle characterized for the base mouse SM22alpha (Tagln) promoter, from which its core is derived.

Applications: Boosting SM22alpha promoter activity for adenovirus-mediated cardiovascular gene transfer targeting arterial vascular smooth muscle cells, where the unmodified SM22alpha promoter alone gives low-level expression compared with viral promoters such as CMV. Suited to reporter and therapeutic gene delivery studies of vascular remodeling, restenosis, and atherosclerosis needing higher-output, smooth-muscle-restricted expression than the base SM22alpha promoter.

Limitations: Characterized with adenoviral, not AAV, delivery, so expression levels and specificity under AAV packaging are not directly established. Inherits the base SM22alpha promoter's restriction to conductive arterial smooth muscle, excluding venous and visceral smooth muscle despite endogenous SM22alpha expression there, and its embryonic activity in cardiac and skeletal muscle lineages.

References

1. Li et al. (1996). Expression of the SM22alpha promoter in transgenic mice provides evidence for distinct transcriptional regulatory programs in vascular and visceral smooth muscle cells. J Cell Biol - Li 1996 SM22a Promoter Specificity