The principle of gene therapy is to use viruses to modify or express new genes within cells in a living being. But you still need to know which genes to use! The goal of the researchers is to find the genes to transform wound cells into keratinocytes. To find them, they start by comparing the gene expression profiles of these two cell types. They then identify 55 genes as potential targets.

By continuing their analyses, they managed to reduce this number to 28, which they then decided to test in-vitro. They express this cocktail of genes to cells similar to those of an open wound, and the results are there. If these cells are grown under conditions similar to those of the body, they form a structure similar to that of normal skin. But 28 genes is still too many to consider gene therapy. Then begins a laborious work where the experiment must be carried out again and again, removing each gene one by one to check if it is really essential. Finally, only 2 genes are essential, DNP63A and GRHL2, and two others greatly improve the efficiency of the transformation, MYC and TFAP2A.