Simultaneous single cell stable expression of 2-4 cDNAs in HeLaS3 using psiC31 integrase system

Area of Science:

• Molecular Biology
• Gene Delivery Technology
• Genomics

Background:

• Efficiently delivering and co-expressing multiple genes within a single cell remains a significant challenge in gene therapy and biotechnology.
• Existing vector systems often struggle with stable integration and stoichiometric gene expression.

Purpose of the Study:

• To develop and validate a novel multi-cDNA expression vector system for stable and stoichiometric delivery of multiple genes.
• To enhance the efficiency of gene integration and expression using the psiC31 recombinase system.

Main Methods:

• Construction of multi-cDNA expression plasmids containing two to three tandem cDNAs.
• Utilizing the psiC31 recombinase system for site-specific integration into HeLaS3 cell chromosomes.
• Analysis of integration events to identify pseudo attP sites and characterization of their sequence motifs.
• Demonstration of successive integration of multiple plasmids and the use of cHS4 insulators to enhance expression.

Main Results:

• Identification of 39 pseudo attP sites in HeLaS3 chromosomes with sequence similarity to the native psiC31 attP.
• Demonstration of site-specific integration of multi-cDNA constructs at these pseudo attP sites.
• Successful successive integration of two different multi-cDNA plasmids, achieving stable co-expression of four transgenes at precise genomic loci.
• Enhanced, stable, and robust transgene expression achieved by incorporating the cHS4 insulator.

Conclusions:

• The developed multi-cDNA expression vector system, when combined with the psiC31 recombinase, offers a powerful tool for stable and efficient multigene delivery.
• The identification of pseudo attP sites facilitates precise genomic integration of multiple transgenes.
• The use of insulators further optimizes transgene expression, paving the way for advanced gene therapy applications.