Nucleofection of phiC31 Integrase Protein Mediates Sequence-Specific Genomic Integration in Human Cells

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• The phiC31 integrase enzyme facilitates sequence-specific DNA integration in mammalian genomes.
• Previous methods relied on delivering phiC31 integrase via plasmid DNA or mRNA.
• The efficiency of using purified phiC31 integrase protein for gene integration was not well-established.

Purpose of the Study:

• To investigate the efficiency of purified phiC31 integrase protein in mediating site-specific genomic integration in human cells.
• To compare the integration efficiency of protein-based delivery with traditional DNA/mRNA methods.
• To assess the utility of protein-mediated integration for therapeutic applications.

Main Methods:

• Preparation of purified 605- and 613-amino-acid versions of phiC31 integrase protein.
• Co-nucleofection of purified phiC31 integrase protein with attB-containing donor plasmids or PCR fragments into human 293 cells.
• PCR analysis to confirm successful genomic integration, including at endogenous pseudo-attP sites.

Main Results:

• Purified phiC31 integrase protein successfully mediated site-specific genomic integration in human cells.
• Integration was confirmed using both donor plasmids and linear PCR fragments.
• Evidence of integration at an endogenous pseudo-attP site was obtained via PCR.
• This protein-mediated approach demonstrated efficiency with different versions of the integrase.

Conclusions:

• Purified phiC31 integrase protein is an effective tool for site-specific gene integration in human cells.
• Protein-based delivery bypasses the need for DNA or mRNA, potentially benefiting sensitive cell types.
• This method holds promise for gene therapy applications, particularly for integrating sequences into therapeutic cells like hematopoietic stem cells or T cells.