while no difference in binding of factor was detected between wild-type polyoma enhancer and the enhancers of the pyec mutants , pyf111 and pyf441 , which had been selected for productive infection of f9 cells , definite differences between wild-type and mutants were observed in the digestion patterns of their naked dnas with either dnaase i or exonuclease iii .
C0086222
enhancers
C0007634
cells