Engineering a Synthesis-Friendly Constitutive Promoter for Mammalian Cell Expression

Since cell-based therapies require the constitutive and stable expression of therapeutic transgenes, lentiviral infection is commonly used to integrate gene material regulated by standard constitutive promoters. Unfortunately, none of the standard or synthetic constitutive promoters can be easily synthesized at low cost due to the presence of repeated subsequences. Thus, in this paper, we designed a synthetic constitutive promoter (named SFCp) that can drive the expression of fluorescent proteins that subsequently trafficked to intended subcellular localizations and the expression of synthetic proteins that rewired the cellular response of Ca2+ to cell morphology changes. Furthermore, SFCp can be used to avoid sequence homology that can theoretically result in loss of genetic material by homologous recombination in tandem constructs. As gene synthesis becomes an indispensable tool in the arsenal of synthetic biology, it is essential to develop a toolbox of gene synthesis friendly components for cell engineering such as constitutive promoters.