Reporter constructs and pEPito plasmids

S/MAR elements (scaffold/matrix attachment regions) are anchor sequences that link independently regulatable chromatin domains to the protein skeleton of the nucleus of eukaryotic cells, creating an autonomous and therapeutically relevant expression system that avoids genomic integration.

In addition to supporting transcription and protecting against inactivation of (foreign) genetic information, a specific feature of these S/MAR elements has proven particularly important for the production of highly efficient plasmid DNA. In addition to supporting transcription and protecting against inactivation of (foreign) genetic information, a specific feature of these S/MAR elements has proven particularly important for the production of highly efficient plasmid DNA. Plasmids that contain a S/MAR element inserted at a defined location, in addition to the therapeutically effective gene, are replicated episomally and passed on as independent units to the daughter cells of the eukaryotic target cell.

In other words, the DNA construct is maintained as an episome for many generations, even in the absence of selection pressure, and will be stably expressed as an autonomous genetic unit without integrating.

The anchor sequence has been successfully reduced to a minimal motif of about 733 base pairs, without significantly affecting stable propagation to the daughter cells.

Key features and benefits of pEPito-based plasmids:

• Episomal replication: After delivery into eukaryotic cells, pEPito plasmids replicate independently of the host genome. This makes them ideal for long-term gene expression studies and reduces the risk of insertional mutagenesis, a critical safety concern for therapeutic applications.
• Stable transgene expression: Unlike conventional plasmids, which are often lost over successive cell generations without selection, S/MAR-based constructs are retained in daughter cells and exhibit robust, long-term expression - even in the absence of antibiotic pressure.
• Non-integrating platform: The plasmid remains extrachromosomal, preserving the genetic integrity of the host cell. This feature is especially important in clinical-grade plasmid DNA for cell and gene therapy applications.
• Reduced silencing: The presence of the S/MAR element supports open chromatin configurations and prevents epigenetic silencing of the transgene, ensuring sustained expression in both dividing and non-dividing cells.

PlasmidFactory offers a range of pEPito plasmids with customizable promoters and also produces minicircle DNA versions of S/MAR-containing vectors, further enhancing delivery efficiency and transgene expression by eliminating bacterial backbone sequences.

Our S/MAR-enabled plasmids can be used in:

• Long-term expression studies in stem cells and primary cells
• Gene therapy research without risk of insertional mutagenesis
• Vaccine development platforms requiring prolonged antigen expression
• Biomanufacturing of recombinant proteins in non-integrative systems

Through licensing agreements, PlasmidFactory provides access to both the pEPI and pEPito vector families, enabling researchers to incorporate this technology into their development pipelines.

All plasmid DNA preparations - whether standard vectors, reporter constructs, or S/MAR-based platforms - are subject to the same high standards of quality control. Optional upgrades to High Quality or GMP-compliant DNA are also available for projects progressing toward clinical applications.