Instruction from pEGFP: The recombinant EGFP vector can be transfected into mammalian cells using any standard transfection method. If required, stable transformants can be selected usingG418 . pEGFP-C1 can also be used simply to express EGFP in a cell line of interest (e.g., as a transfection marker).
However, after SV40 promoter, which promotes transcription of NeoR in eukaryotic cells, there is an ATG before NeoR. I thought the translation will start at this ATG, not NeoR' ATG. and frameshift happens.