The p3XFLAG-CMV?-10 Expression Vector is a 6.3 kb derivative of pCMV5 used to establish transient or stable intracellular expression of N-terminal 3XFLAG? fusion proteins in mammalian cells. The vector encodes three adjacent FLAG? epitopes (Asp-Tyr-Lys-Xaa-Xaa-Asp) upstream of the multiple cloning region. This results in increased detection sensitivity using ANTI-FLAG M2 antibody. The third FLAG epitope includes the enterokinase recognition sequence, allowing cleavage of the 3XFLAG peptide from the purified fusion protein. Efficiency of replication is optimal when using an SV40 T antigen expressing host.