Further improvement in BE4 was
achieved through fusion of Gam protein derived from Phage Mu. The Gam protein
fusion product in the form of BE3-Gam and BE4-Gam vectors helps in binding with
DSBs leading to reduction in indels and an improvement in product purity. Thus
fusion of Mu Gam protein protein to BE3 and BE4 gave one of the best base
editors for conversion of C:G to T:A15 (Figure 9).