circular psv2gpt plasmid dna was linearized by digestion with ecori and reacted with n-ethyl-n-nitrosourea in vitro to a level of about one o6-etgua residue per dna molecule , labeled with 32p , and subsequently incubated with extracts prepared from l929 mouse fibroblasts and with mab er-6 .
C0012925
circular
C0012854
dna molecule