Fig. 1

Homology-directed recombination repair (HDR) assay. HeLa-DR-GFP cells are characterised by the presence of two different inactive copies of the gene encoding green fluorescent protein (GFP) integrated in a single locus in the genome. The first copy (Sce-GFP) is inactive due to the presence of a I-SceI cleavage site, and the second copy (iGFP) is truncated at both ends. Transfection of a plasmid encoding the I-Scel endonuclease will result in a double-stranded DNA break of the Sce-GFP copy. During HDR, BRCA1 will use the iGFP copy as a sequence donor to repair the break, and GFP will subsequently be expressed. Figure inspired from [22]