Despite various advances in the use of gene therapy to treat HIV-1 infection, and thefact that TALEN and CRISPR-Cas9 have been used in most studies, including targetingof the CCR5 gene, nothing is known about possible variations in the patterns andefficiencies of TALEN and CRISPR-Cas9 in editing the beginning of the CCR5 gene.Such knowledge is important for corroborating the choice of a given tool in basicresearch and gene therapy targeting of the CCR5 gene. Here, CCR5 is linked to HIV-1 infection.