Vector that provides dominant selectable marker for resistance to antibiotic G418 in mammalian cell lines. Restriction digests of the vector gave the following sizes (kb) : EcoRI-8.6 ; HindIII-4.6, 3.1, 1.4, 0.64 ; PvuII-4.0, 2.1, 1.1, 0.74, 0.64, 0.37. Depositors: Paul Berg, Biochemistry Department Stanford University Medical Center Applications: Shuttle vector, Expression vector