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The BacMam system allows you to run the assays you need in relevant cellular models quickly with high quality results. The technology offers the following key advantages:

  • Efficient transduction of mammalian cell lines, including primary cells and stem cells
  • Safety (non-replicating in mammalian cells) and lack of observable cytopathic effect
  • Frozen storage of pre-transduced cells generates assay-ready cells
  • Easy modulation of gene expression by varying transduction amounts
  • Reproducible co-transduction and expression of multi-component complexes at the right stoichiometry

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Mechanism of BacMam-mediated Gene Delivery

The BacMam technology is based on double-stranded DNA insect viruses (baculovirus) as vehicles to efficiently deliver and express genes in mammalian cells. The baculovirus has been modified by engineering of a mammalian expression cassette for transgene expression in mammalian cells. Baculoviruses are non-replicating in mammalian cells and thus have an excellent safety profile combined with being well-tolerated by cells. BacMam reagents have been used in cell based assays, live cell imaging, stem cell biology and many other applications (View references).

To introduce genes into mammalian cells, a standard transduction process is used (Figure 1). BacMam particles are taken up by endocytosis and released for transcription and expression following migration to the nucleus.  Gene expression begins within 4–6 hours of transduction and is at near maximum level within 24 hours of transduction. 

Depending on transduction efficiency, cell type and cell division rate, the transgene remains detectable from 5 to 14 days.

 

BacMam transduction process

  Figure 1. BacMam-mediated gene delivery.

BacMam Workflow and Protocols

BacMam reagents are used in your normal workflow as any other reagent for cell-based research; take the reagent from the fridge, add it to cells, incubate and assay (Figure 2). Transduction is efficient and reproducible in most cell lines, including primary and stem cells. The BacMam platform enables easy transduction of large quantities of cells in batch mode; transduced cells can stored frozen in aliquots for later use, providing assay-ready cells when you need them—with no loss of activity. Cells can be assayed within hours of thawing and plating.

BacMam 2.0 Workflow
Figure 2—BacMam 2.0 workflow. 
Simply culture cells, add virus, incubate, and visualize BacMam 2.0 fluorescent protein expression.

BacMam technology is extremely well tolerated without apparent cytopathic effects, even at very high (1,000) virus particle to cell [multiplicity of infection (MOI)] ratios. Gene expression can therefore be easily titrated to a desired level by adjusting the dose. There are two basic transduction protocols: adherent cell transduction (Figure 3) and suspension cell transduction (Figure 4). Adherent cell transduction is more efficient, whereas transduction of cells in suspension gives a more convenient workflow and is recommended for high throughput based assay screening applications.

 


 
Figure 3. Adherent cell transduction protocol.
 

 


 
Figure 4. Suspension cell transduction protocol.
 

References

  1. Boyce, FM & Bucher, NL (1996) Baculovirus-mediated gene transfer into mammalian cells. PNAS, 93:2348-2352
  2. Kost, TA, Condreay, JP & Jarvis, D.L. (2005) Baculovirus as versatile vectors for protein expression in insect and mammalian cells. Nature Biotechnol 23:567-575.
  3. Condreay JP, Kost TA (2007) Baculovirus Expression Vectors for Insect and Mammalian Cells. Current Drug Targets 8(10): 1126-1131.
  4. Ames RS, Kost TA, Condreay JP (2007) BacMam technology and its application to drug discovery. Expert Opin Drug Discov 2:1669-1681.
  5. Kost TA, Condreay JP, Ames RS, Rees S, Romanos MA (2007) Implementation of BacMam virus gene delivery technology in a drug discovery setting. Drug Disc Today 12:396-403.
  6. Hu Y-C (2008) Baculoviral vectors for gene delivery: A review. Current Gene Ther 8:54-65.
  7. Airenne KJ, Mähönen AJ, Laitinen OH, Ylä-Herttuala S (2009) Baculovirus-Mediated Gene Transfer: An Emerging Universal Concept, pp 263-291.  In Gene and Cell Therapy, Third Edition, NS Templeton Ed. CRC Press, Boca Raton, FL.