Does anyone know if CMV or EF1a which is better to express gene by Safe Harbor CRSPR knock in U2OS cells. Some cell line doesn’t express through CMV promoter in some cell lines. Is it the case for the U2OS cell line if I use CMV as a donor plasmid expression for the safe harbor site CRISPR knockin. I know CMV does express protein in regular over expression set up but not sure for the Safe harbor CRISPR knock in set up. Also if they both express then what number difference I should expect for this cell line for both the promoters.