Neomycin is more efficient than streptomycin in suppressing frameshift mutations

The effects of streptomycin and neomycin on the phenotypic suppression of frameshift mutations in the lacZ gene of Escherichia coli and on the efficiency of suppression of amber mutations in T4 phage by the informational supE tRNA nonsense suppressor were compared. Neomycin stimulated much more efficiently than streptomycin the phenotypic suppression of frameshift mutations. Because neomycin favors mismatches of the central codon base whereas streptomycin favors mismatches of the first codon base, this result suggests that mismatching of the central codon base pair and shifting of the reading frame are two correlated phenomena. In contrast, both streptomycin and neomycin stimulated about equally the efficiency of the tRNA nonsense suppressor, an effect probably related to their interference with the proofreading control in tRNA selection.Key words: streptomycin, neomycin, suppression of frameshift mutations, translational accuracy.