Targeted gene therapy of xeroderma pigmentosum cells using meganuclease and TALEN

• Published in: PloS one 2013-11, Vol.8 (11), p.e78678
• Main Authors: Dupuy, Aurélie, Valton, Julien, Leduc, Sophie, Armier, Jacques, Galetto, Roman, Gouble, Agnès, Lebuhotel, Céline, Stary, Anne, Pâques, Frédéric, Duchateau, Philippe, Sarasin, Alain, Daboussi, Fayza
• Format: Article
• Language: English
• Subjects: Base Sequence; C cells; Cell Line; Clonal deletion; CpG islands; Deoxyribonucleases - genetics; Deoxyribonucleic acid; Design optimization; DNA; DNA binding proteins; DNA Cleavage; DNA damage; DNA Methylation; DNA Repair; DNA-Binding Proteins - genetics; Epigenesis, Genetic; Experimental design; Gene deletion; Gene therapy; Genes; Genetic Therapy; Homologous recombination; Homology; Humans; Hypersensitivity; Insertion; Lesions; Life Sciences; Loci; Methylation; Mutagenesis; Mutation; Neoplasms; Nuclease; Nucleases; Nucleotide excision repair; Phenotype; Protein Engineering; Repair; Skin; Stem cells; Transcription activator-like effector nucleases; Ultraviolet radiation; Xeroderma pigmentosum; Xeroderma Pigmentosum - therapy; XPC protein; Zinc; Zinc finger proteins
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0078678

Xeroderma pigmentosum group C (XP-C) is a rare human syndrome characterized by hypersensitivity to UV light and a dramatic predisposition to skin neoplasms. XP-C cells are deficient in the nucleotide excision repair (NER) pathway, a complex process involved in the recognition and removal of DNA lesions. Several XPC mutations have been described, including a founder mutation in North African patients involving the deletion of a TG dinucleotide (ΔTG) located in the middle of exon 9. This deletion leads to the expression of an inactive truncated XPC protein, normally involved in the first step of NER. New approaches used for gene correction are based on the ability of engineered nucleases such as Meganucleases, Zinc-Finger nucleases or TALE nucleases to accurately generate a double strand break at a specific locus and promote correction by homologous recombination through the insertion of an exogenous DNA repair matrix. Here, we describe the targeted correction of the ΔTG mutation in XP-C cells using engineered meganuclease and TALEN™. The methylated status of the XPC locus, known to inhibit both of these nuclease activities, led us to adapt our experimental design to optimize their in vivo efficacies. We show that demethylating treatment as well as the use of TALEN™ insensitive to CpG methylation enable successful correction of the ΔTG mutation. Such genetic correction leads to re-expression of the full-length XPC protein and to the recovery of NER capacity, attested by UV-C resistance of the corrected cells. Overall, we demonstrate that nuclease-based targeted approaches offer reliable and efficient strategies for gene correction.