2-HYDROXYAMINO-1-METHYL-6-PHENYLIMIDAZO[4,5-B]PYRIDINE INDUCTION OF RECOMBINATIONAL MUTATIONS IN MAMMALIAN-CELL LINES AS DETECTED BY DNA-FINGERPRINTING

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhlP) is the most abundant mutagenic heterocyclic amine in cooked foods. Two mouse tumor cell lines, BMT11 and FM3A, were exposed to its proximate form, 2-hydroxyamino-1 -methyl-6-phenylimidazo[4,5-b]pyridine (N-OH-PhlP). Fifty-six subclones of BMT11 and 39 subclones of FM3A were isolated and analyzed by DNA fingerprinting. Treatment with 10-20 mu M N-OH-PhlP gave rise to extra bands or shifted bands, but treatment without N-OH-PhlP did not. This suggests that mutations resulting from recombination were induced. The mutation frequencies were 21-53% and 22-35% for BMT11 and FM3A, respectively. These findings suggest that PhlP induces recombinational mutations. (C) 1994 Wiley-Liss, Inc.