Correction of a Factor VIII genomic inversion with designer recombinases?

Despite advances in nuclease-based genome editing technologies, correcting human disease-causing genomic inversions remains a challenge. Here, we describe the potential use of a recombinase-based system to correct a 140 kb int1h inversion frequently found in patients diagnosed with Hemophilia A. With the use of directed molecular evolution, we developed a linked heterodimeric recombinase system (RecF8) achieving 30% inversion of the target sequence in human tissue culture cells. Transient RecF8 treatment of endothelial cells, differentiated from int1h patient derived iPSCs, resulted in prominent correction of the inversion and restored Factor VIII mRNA expression. Our data suggest that the development of designer-recombinases represent an efficient and specific mean towards treatment of large gene inversions causing monogenic diseases. Overall design: ChIP-Seq based examination of RecF8 recombinase binding sites in a human cell line.