What is the size of the dCas9-VPR protein and what antibody do you recommend for confirmation of expression of the dCas9-VPR?

The VPR activators add additional 536 amino acids to dCas9 which then shift the molecular weight of the dCas9-VPR to approximately ~220 kDa. The protein could be detected using Cas9 antibodies (for example: Novus Biologicals cat #NBP2-36440).