pEGFP-C1 transformation

D.K. dk at
Sat Dec 21 18:21:39 EST 2002

In article <au2nlk$71g$1 at>, "Carnac" <carnac at> wrote:
>Hey, all.  :)
>I am currently attempting to transform electrocompetent cells with a
>pEGFP-C1 vector/insert plasmid, and am having very limited success - in the
>range of absolutely no colonies, to very few.  I'm using a 1 uL volume of
>plasmid to 20 uL of competent cells in a 1 mm cuvette.  The plasmid  and
>insert digest was with SAL-I and Bam-HI, where the SAL digest was performed
>for 2 hours prior to the adding of the BAM enzyme, for a further hour.  The
>cut plasmid plus insert were then ligated with T4 ligase at room temperature
>for 1 hour prior to transformation.  I used a 3:1 insert:vector ratio for
>recombination.  After transformation, the cells were iced for 5 minutes, and
>then 1 mL of LB was adding.  The cells were transferred out of the cuvette,
>and allowed to recover for 1 hour, prior to plating on media containing
>kanamycin.  The plate was then dried under a flame for 20 minutes.
>Has anybody else had any problems transforming E coli with this plasmid?

Are competent cells really competent? What's the transformation efficiency 
with control plasmid? Dis you do a control to make sure ligase works too?


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