two additional activities have been localized to the bamhi-c dna fragment : ( i ) a dna sequence that could functionally substitute for the simian virus 40 enhancer and promoter elements controlling the expression of g-418 resistance and ( ii ) a dna sequence which , although not sufficient to allow extrachromosomal plasmid maintenance , enhanced the frequency of transformation to g-418 resistance in ebv-positive ( but not ebv-negative ) cells .
C0086860
elements
C0007634
cells