title: 5'-Cytosine-phosphoguanine (CpG) methylation impacts the activity of natural and engineered meganucleases.
abstract: In this study, we asked whether CpG methylation could influence the DNA binding affinity and activity of meganucleases used for genome engineering applications. A combination of biochemical and structural approaches enabled us to demonstrate that CpG methylation decreases I-CreI DNA binding affinity and inhibits its endonuclease activity in vitro. This inhibition depends on the position of the methylated cytosine within the DNA target and was almost total when it is located inside the central tetrabase. Crystal structures of I-CreI bound to methylated cognate target DNA suggested a molecular basis for such inhibition, although the precise mechanism still has to be specified. Finally, we demonstrated that the efficacy of engineered meganucleases can be diminished by CpG methylation of the targeted endogenous site, and we proposed a rational design of the meganuclease DNA binding domain to alleviate such an effect. We conclude that although activity and sequence specificity of engineered meganucleases are crucial parameters, target DNA epigenetic modifications need to be considered for successful gene editions.
authors: CELLECTIS S.A., 8 Rue de la Croix Jarry, 75013 Paris, France. julien.valton@cellectis.com
authors: Julien
authors: J
authors: Valton
authors: Fayza
authors: F
authors: Daboussi
authors: Sophie
authors: S
authors: Leduc
authors: Rafael
authors: R
authors: Molina
authors: Pilar
authors: P
authors: Redondo
authors: Rachel
authors: R
authors: Macmaster
authors: Guillermo
authors: G
authors: Montoya
authors: Philippe
authors: P
authors: Duchateau
mesh_terms: D018899:CpG Islands; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004262:DNA Restriction Enzymes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D044127:Epigenesis, Genetic; D057809:HEK293 Cells; D006801:Humans; D017434:Protein Structure, Tertiary
chemical_list: D004247:DNA; D004262:DNA Restriction Enzymes; C048901:endodeoxyribonuclease CreI