pEF1α-Myc is a mammalian expression vector that constitutively expresses a protein of interest fused to an N-terminal c-Myc tag, even after stable integration of the vector into the host cell genome. Stable, constitutive expression of the tagged protein is driven by the human elongation factor 1 alpha (EF1α) promoter, which allows expression of the fusion without the transgene silencing associated with CMV promoters. The myc-tagged protein of interest can be detected by either western analysis or fluorescence microscopy using an anti-myc antibody.