A Novel Cre/lox71-Based System for Inducible Expression of Recombinant Proteins and Genome Editing

In this study, we developed a novel Cre/lox71-based system for the controlled transient expression of target genes. We used the bacteriophage P1 Cre recombinase, which harbors a short, highly specific DNA-binding site and does not have endogenous binding sites within mouse or human genomes. Fusing the catalytically inactive form of Cre recombinase and the VP64 transactivation domain (VP16 tetramer), we constructed the artificial transcription factor Cre-VP64. This transcription factor binds to the lox71 sites within the promoter region of the target gene and, therefore, upregulates its expression. We tested the Cre-VP64/lox71 system for the controlled expression of several genes, including growth factors and the genome editor CRISPR/Cas9, and obtained superior efficiency in the regulation of transgene expression, achieving a high expression level upon induction together with low basal activity. This system or its modified forms can be suggested as a novel effective tool for the transitory controlled expression of target genes for functional genomic studies, as well as for gene therapy approaches.

Automated summary

In this study, a novel Cre/lox71-based system for the controlled transient expression of target genes was developed. The system utilizes the bacteriophage P1 Cre recombinase, which has a highly specific DNA-binding site without endogenous binding sites within mouse or human genomes. By fusing the catalytically inactive form of Cre recombinase with the VP64 transactivation domain, an artificial transcription factor Cre-VP64 was constructed. This transcription factor binds to the lox71 sites within the promoter region of the target gene and enhances its expression. The system demonstrated superior efficiency in regulating transgene expression with high expression level upon induction and low basal activity. This system, along with its modified forms, can serve as an effective tool for the temporary controlled expression of target genes in functional genomic studies and gene therapy approaches.