1 reply to this topic

[Dr_Watson]

hi everyone,

I have a strain which is DE3 and I have the same one without DE3. I transformed both with the same plasmid and tried inducing the protein with IPTG and with arabinose. The results for IPTG induction are ok, but I have a problem with the arabinose. In the strain that is DE3 I don't have any expression of the protein. The expression is ok in the same strain that is not DE3.

So finally the question: is there something on the DE3 lysogen that would explain why I don't have any expression using arabinose?

thanks for the reply, and have a nice weekend.

DrW

[pDNA]

did you made your DE3 strain on your own? ...what was the source strain?

there is the minor possibility that if the attB (the normal attachment site of phage lambda) is absent the phage can integrate in other sites ...like the ara operon ...here is a link to the publication describing that.

Maybe you are unlucky and the phage hit the gene resposible for uptake of arabinose therefore no induction is taking place!

Just a theory ...maybe you can give us more information on your experiment?

Regards,
p

Dr_Watson, on 18 February 2011 - 02:45 PM, said:

hi everyone,

I have a strain which is DE3 and I have the same one without DE3. I transformed both with the same plasmid and tried inducing the protein with IPTG and with arabinose. The results for IPTG induction are ok, but I have a problem with the arabinose. In the strain that is DE3 I don't have any expression of the protein. The expression is ok in the same strain that is not DE3.

So finally the question: is there something on the DE3 lysogen that would explain why I don't have any expression using arabinose?

thanks for the reply, and have a nice weekend.

DrW