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Generation of a stable cell line: A positive control plasmid works, but I cannot obtain stable clones with my construct of interest. What could be the reason?

One reason could be that your gene product is toxic to the cells. We recommend testing the construct for expression of the gene of interest by transient Nucleofection™ of your cells. If the proportion of expressing cells drops between 4 and 48 hours...

How long does it take to obtain stable transfectants?

Depending on individual cell type and doubling rate, selection of stable transfectants will take between 7 and 28 days. Expansion and characterization of single cell clones will take several weeks in addition.

I have a very high transfection efficiency but most of my cells die during selection, is this to be expected?

This is the normal pattern you should expect to see. Only a small proportion (1/10,000 to 1/100) of all transfected cells will integrate the transfected DNA into their genome and become stable transfectants. The remaining cells lose the transfected...

What selection markers can I use for stable transfections?

The most commonly used marker is the neomycin phosphotransferase (neo) gene that confers resistance to G418 to eukaryotic cells. Other markers are Puromycin, Hygromycin, Zeocin, or the HPRT gene that can be used in HPRT-deficient cells.


How often should I change the medium during selection of stable clones after Nucleofection?

Every 2-3 days. This eliminates potentially toxic substances produced by dying cells and secondly, it keeps the concentration of the antibiotic at a constant level.

How many stable clones will I get from one transfection?

This depends on the respective cell type (transfection efficiency, viability and integration frequency). If it is important to you to know the frequency of stable integrants before carrying out your actual experiments, the frequency should be...

Following Nucleofection, I cannot obtain stable clones from single cells, what could be the reason?

Some cell lines need certain cell densities to proliferate. For those cells you can try using conditioned medium for setting up limiting dilution or culturing single cells together with feeder cells.

In my Nucleofection Experiment I see lower expression with my IRES construct in comparison with you pmax-GFP control. Do you have any information about the different expression profiles?

The original attenuation of the IRES sequence was performed to allow for a greater difference between the expression levels of the upstream gene of interest and the downstream reporter gene. If the downstream reporter gene, the product of less than...

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