A SPECTRUM OF MUTATIONS INDUCED BY CROTONALDEHYDE IN SHUTTLE VECTOR PLASMIDS PROPAGATED IN HUMAN-CELLS

A spectrum of crotonaldehyde-induced mutations in the supF gene of the shuttle vector plasmid pMY189 replicated in human fibroblast cells wa s examined. Base sequence analysis of 104 plasmids with mutations in t he supF gene revealed that the majority of the mutations were base sub stitutions (85%) and the rest were frameshifts (15%), A single base su bstitution was most frequently found (47%), while 25% had multiple bas e substitutions and interestingly 13% had tandem (adjacent two) base s ubstitutions, Of the base substitution mutations, 50% were G:C-->T:A t ransversions and 23% were G:C-->A:T transitions. The mutations were no t distributed randomly but were located at several hotspots, most of w hich were G:C base pairs in 5'-AAGG-3' (or 5'-CCTT-3') sequences, Prod uction of propanodeoxyguanosine adducts may be related to such specifi city in the mutation spectrum.