Biochem/physiol Actions

G 418 blocks polypeptide synthesis by interfering with ribosomal function and inhibiting protein elongation.

Mode of Action: Blocks polypeptide synthesis by inhibiting protein elongation. For use in the selection and maintenance of eukaryotic cells stably transfected with neomycin resistance genes.

Mode of Action: Blocks polypeptide synthesis by inhibiting protein synthesis at the level of the 70S and 80S ribosomes. For use in the selection and maintenance of eukaryotic cells stably transfected with neomycin resistance genes.

Other Notes

Aminoglycoside antibiotic similar in structure to gentamicin, neomycin and kanamycin.

Application

G 418 is a Micromonospora-produced aminoglycoside antibiotic with activity against protozoa and helminths¹. G 418 disulfate salt is used for selection and maintenance of prokaryotic and eukaryotic cells transfected with a iNOS promoter construct and neomycin resistance gene².

G 418 is an aminoglycoside antibiotic similar in structure to gentamycin. It is normally toxic towards eukaryotic and prokaryotic cells, but is useful for selection of cells stably transfected with neomycin resistance gene (Neo). The optimal concentration for selection and maintenance must be determined for each cell line. For bacteria and algae, concentrations of 5 μg/ml or less are recommended. Animal cells may require up to 300-500 μg/ml. Typically, resistance is conferred by one of two dominant genes of bacterial origin, which can be expressed in eukaryotic cells. Cells that are multiplying will be affected sooner than those are quiescent. Cells in log phase may require three to seven days for selection. In general, concentrations of approximately 400 μg/ml for selection and 200 μg/ml for maintenance are required for mammalian cells.

1. G. H. Wagman, R. T. Testa, et al., Antibiotic G-418, a New Micromonospora-Produced Aminoglycoside with Activity Against Protozoa and Helminths: Fermentation, Isolation, and Preliminary Characterization Antimicrob. Agents Chemother. 6, 144-149, (1974)

2. Outi Sareila, Mari Hämäläinen, et al., Orazipone Inhibits Activation of Inflammatory Transcription Factors Nuclear Factor-B and Signal Transducer and Activator of Transcription 1 and Decreases Inducible Nitric-Oxide Synthase Expression and Nitric Oxide Production in Response to Inflammatory Stimuli J. Pharmacol. Exp. Ther. 324, 858-866, (2008)

Lin-Cereghino J, Hashimoto MD, et. al., Direct selection of Pichia pastoris expression strains using new G418 resistance vectors. Yeast 25, 293-299, (2008)

Agaphonov M, Romanova N, Choi ES, et. al., A novel kanamycin/G418 resistance marker for direct selection of transformants in Escherichia coli and different yeast species. Yeast 27, 189-195, (2010)

Canaani, D., and Berg, P., Regulated expression of human interferon β1 gene after transduction in to cultured mouse and rabbit cells. Proc. Natl. Acad. Sci. U. S. A. 79, 5166-5170, (1982)

Southern, P., and Berg, P., Transformation of mammalian cells to antibiotic resistance with a bacterial gene under control of the SV40 early region promoter. J. Mol. Biol. 1, 327-341, (1982)

Halaban, R., and Alfano, F., Selective elimination of fibroblasts from cultures of normal human melanocytes. In Vitro Cell. Dev. Biol. 20, 447-450, (1984)

Ursic, D., et al., A new antibiotic with known resistance factors, G418, inhibits plant cells. Biochem. Biophys. Res. Commun. 101, 1031-1037, (1981)

Bar-Nun, S., et al., G-418, an elongation inhibitor of 80 S ribosomes. Biochim. Biophys. Acta 741, 123-127, (1983)

Kingston, R, Ausubel, F. et al., Stable transfer of genes into mammalian cells. Short Protocols in Molecular Biology 2nd ed., New York , (1992), 9.14