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Reference information for laboratory staff. Blasticidin S is sold for research use only; follow your institution’s safety rules and the supplier’s safety data sheet.
Short answer
Blasticidin (blasticidin S) is a nucleoside antibiotic from Streptomyces griseochromogenes that inhibits protein synthesis in both prokaryotic and eukaryotic cells. Researchers use it to select cells that carry a plasmid with a blasticidin S deaminase gene, BSD or bsr. The manufacturer’s starting ranges are 50-100 µg/mL for E. coli (in low-salt LB), 25-300 µg/mL for yeast and 2-10 µg/mL for mammalian cells, and each should be confirmed with a kill curve.
Definition and scope
Blasticidin S is supplied as the hydrochloride salt (formula C17H26N8O5-HCl, molecular weight 458.9). The Thermo Fisher product sheet describes a ready-made solution at 10 mg/mL in 20 mM HEPES, pH 7.2-7.5, labelled for research use only.1 It is a selection agent: cells without a resistance gene are killed, so only cells that took up and express the marker survive. Because it acts on both bacteria and eukaryotic cells, the same drug can select in E. coli, yeast and mammalian culture, although the working concentration differs for each.
This page covers the antibiotic and its selection use. For how a selectable marker fits into a vector, see plasmid design; for stable-line workflows that use a marker after viral delivery, see the lentiviral transduction protocol guide.
Blasticidin mechanism of action
The product information sheet states that blasticidin S inhibits protein synthesis in both prokaryotic and eukaryotic cells.1 That broad activity is why a single resistance gene works across host types. This page does not go beyond that statement; for the molecular detail of ribosome binding, consult the primary literature.
Blasticidin resistance genes: BSD and bsr
Resistance comes from either of two blasticidin S deaminase genes. Both enzymes convert blasticidin S into a nontoxic deaminohydroxy derivative.1 UniProt’s reviewed entries classify the enzyme as EC 3.5.4.23, catalysing blasticidin S to deaminohydroxyblasticidin S plus ammonium; it also acts on cytomycin and acetylblasticidin S.2
| Gene | Source organism (per manufacturer) | UniProt reviewed entry |
|---|---|---|
| BSD | Aspergillus terreus | P0C2P0 and P0C2P1 |
| bsr | Bacillus cereus | P33967 |
UniProt also holds a reviewed blasticidin-S deaminase entry from Coccidioides immitis (P0CI02), which is not one of the two marker genes named on the product sheet.2 When you buy or build a vector, check which of the two genes it carries, since the sequence name on the map is what you will cite in methods.
Blasticidin selection and working concentration by host
The manufacturer’s sheet gives these starting ranges. They are ranges, not fixed values.1
| Host | Starting range | Condition stated by the manufacturer |
|---|---|---|
| E. coli | 50-100 µg/mL | Use low-salt LB (under 5 g NaCl per litre; salt below 90 mM, pH not above 7.0). Higher salt means the antibiotic does not select. |
| Yeast | 25-300 µg/mL | Run a kill curve for each species, strain and medium. |
| Mammalian cells | 2-10 µg/mL | Varies by cell line; determine with a kill curve. |
For a dense lawn of bacteria on a plate, the same sheet advises raising the concentration to 100 µg/mL.1
Blasticidin kill curve: design checklist
A kill curve finds the lowest concentration that kills untransduced cells of your own line in your own medium. The manufacturer’s mammalian procedure, summarised:1
- Plate cells at about 25% confluence in a set of six plates and let them adhere overnight.
- Next day, change to medium containing a graded series, for example 0, 2, 4, 6, 8 and 10 µg/mL.
- Replenish the selective medium every 3-4 days.
- Choose the lowest concentration that kills the cells within 10-14 days.
The yeast guidance on the same sheet asks for a kill curve per species, strain and medium, so the checklist logic carries over, but use the yeast ranges above as the dilution series.
Storage and handling
- Store the stock at -20 to -5 °C in a freezer that is not frost-free, protected from light; the sheet gives 9 months’ stability under those conditions.1
- Medium containing blasticidin is stable at 4 °C for up to 2 weeks.1
- Avoid repeated freeze-thaw cycles and discard the unused thawed portion.1
- Wear gloves, a mask, a lab coat and safety glasses, and read the safety data sheet.1 Our guide on finding a safety data sheet explains where to obtain one, and the -80 freezer management entry covers freezer practice generally.
Where it matters for lab decisions
Three points from the sources change outcomes at the bench. First, salt and pH in bacterial media can silently defeat selection, so a plate that grows everything is a media problem before it is a plasmid problem.1 Second, because the yeast range alone spans twelvefold (25-300 µg/mL), copying a number from another lab’s paper is weaker than running your own kill curve. Third, medium with the drug has a short stated shelf life at 4 °C, so make selective medium in amounts you will use within the stated window.1
Common misunderstandings
- “One concentration fits all cells.” The manufacturer gives host ranges and says mammalian concentration varies by cell line.1
- “Any LB works for E. coli.” The sheet specifies low-salt LB; high salt is listed as a cause of non-selection.1
- “A frost-free freezer is fine.” The sheet specifies a freezer that is not frost-free.1
- “BSD and bsr are the same gene.” Both encode blasticidin S deaminases but come from different organisms and are separate entries in UniProt.1,2
FAQ
What is blasticidin used for?
Selecting cells that carry a BSD or bsr resistance gene after transformation, transfection or transduction.1
What is a typical blasticidin concentration for mammalian cells?
The manufacturer lists 2-10 µg/mL as a starting range, to be fixed per cell line with a kill curve.1
How long does blasticidin selection take?
The manufacturer’s kill-curve procedure aims for a concentration that kills untransduced cells within 10-14 days, with selective medium replaced every 3-4 days.1
How should blasticidin be stored?
At -20 to -5 °C in a non-frost-free freezer, protected from light; stable 9 months. Medium containing it keeps up to 2 weeks at 4 °C.1
Sources
- Thermo Fisher Scientific, Blasticidin S HCl product information sheet, Pub. No. MAN0000780 Rev. A.0 (11 July 2016): https://documents.thermofisher.com/TFS-Assets/LSG/manuals/blasticidin_man.pdf. Read 2026-11-08.
- UniProt Knowledgebase, reviewed entries for blasticidin-S deaminase (EC 3.5.4.23): UniProt search. Read 2026-11-08.
