Vector 3
The Vector 3 is 5.4kb in length, and contains the the amp resistance gene, conferring selection of the plasmid in E. coli., the kanamycin resistance gene (neomycin for mammalian selection), and the CMV promoter upstream of the cDNA insert. The SV40 origin allows for replication in mammalian cells, the ColE1 origin is the bacterial origin of replication, and the f1 origin is the filamentous phage origin of replication.