- Processing of MucA protein is required for spontaneous and benzo[a]pyrene-induced reversion of the Escherichia coli trpA23 missense mutation by G.C-T.A transversions: effect of a deficiency in the MutY DNA glycosylase. Urios, A., Herrera, G., Aleixandre, V., Blanco, M. Mutat. Res. (1994)