Blasticidin S is a peptidyl nucleoside antibiotic isolated from Streptomyces griseochromogenes. It is a potent inhibitor of protein synthesis in in bacteria and eukaryotes, while also active against fungi, nematodes, and tumor cells. Blasticidin S acts by blocking hydrolysis of peptidyl-tRNA induced by release factors and inhibits peptide bond formation. It is used as a selection agent in both mammalian cells and bacterial cells. The recommended working concentration ranges from 1 to 30 μg/mL depending on the cell line and 25–100 μg/mL for bacterial selection. Cell death occurs rapidly, and blasticidin-resistant stable mammalian cell lines can be generated in less than one week.

Resistance to blasticidin S is conferred by BSR and BSD, isolated from Bacillus cereus K55-S and Aspergillus terreus respectively. The BSR resistance gene encodes blasticidin S deaminase, which catalyzes the conversion of blasticidin S to deaminohydroxyblasticidin S. Deaminohydroxyblasticidin S is a biologically inactive derivative of blasticidin S and does not interact with or inhibit prokaryotic or eukaryotic ribosomes. The BSD resistance gene also encodes a blasticidin S deaminase, which catalyzes a similar reaction to the BSR deaminase. For bacterial selection purposes, the salt content of the LB medium must remain low (less than 90 mM) and the pH should not exceed 7.0 to maintain the activity of basticidin S. A kill curve is recommended in order to determine the minimum effective blasticidin S concentration to kill non-resistant cells.

Applications
View detailed protocols on blasticidin selection in mammalian cells, E. coli, and yeast.