BE3 and YEE-BE3 mRNA was transcribed using the mmol/LESSAGEmmol/LACHINE T7 ULTRA kit (Life Technologies) following the manufacturer’s instruction. gRNA-1 transcribed using the MEGAshortscript T7 kit (Life Technologies) following the manufacturer’s instruction. mRNAs and gRNAs were subsequently purified using the MEGAclear kit (Life Technologies) and resuspended in RNase-free water.