In article <199511221416.JAA04468 at mail2.sas.upenn.edu>,
David Roos <droos at sas.upenn.edu> wrote:
>Paul Horrocks recently noted difficulties in functionally expressing GFP
>in the malaria parasite Plasmodium falciparum. We have had similar lack
>of success with attempts at expression in the related protozoan parasite
>Toxoplasma gondii. It is my understanding that at least 6 other groups
>have also failed in to express GFP in Plasmodium or in Toxoplasma.
>>We have cultured parasites in a high oxygen environment, but to no avail.
>Lowering the culture temperature to 30 or 25 degrees also has no
>detectable effect. I would not conclude from our limited experience that
>this project cannot succeed, but would be interested to hear of efforts
>by others. In particular, we have never obtained antibody to determine
>if the GFP protein is even made. It would also be interesting to try the
>'red-shift' mutation (and other mutants).
>I have heard from more than one source that expression of GFP in organisms
with strict codon usage requires the reengineering of GFP to avoid rare
codons. Looking at Plasmodium falciparum's codon usage indicates that
several codons are quite rare indeed (less than 10 per 35000). I would
take a look at Toxoplasma codon usage to see if the same problem exists.
Bill
--
William J. Buikema Phone: (312)702-1081 e-mail: hetman at uchicago.edu
Dept. Mol. Genet. & Cell Biol. / / --- --- /|/| /| /| /
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