N4-hydroxycytidine: a mutagen specific for AT to GC transitions

N4-Hydroxycytidine is a mutagen of the base-analog type and one of the products formed by treatment of cytidine with hydroxylamine. In this communication evidence is presented showing that, in contrast with other known base analogs, N4-hydroxycytidine results mainly, if not exclusively, in AT leads to GC transitional alterations in Escherichia coli K12.