摘要
Two recent articles 1,2 published in Science separately reported,for the first time,that a cytosine base editor but not an adenine base editor could induce considerable off-target effects.The advent of CRISPR-Cas9 as an RNA-guided site-specific DNA endonuclease facilitates genome modification in a precise and efficient way and brings a new dawn to targeted gene therapy.3,4 However,this genome editing tool has suffered from controversy due to its off-target effects.In 2016,based on CRISPR-Cas9,David Liu and coworkers developed the first cytosine base editing tool(CBE,a cytosine base editor which can readily mutate a G·C base pair to an A·T base pair),which marked a second inflection point in the advancement of genome-modifying capabilities.
