>Benedikt,
>CFP has a much lower quantum efficiency than GFP or YFP. If your pollen
tubes
>are growing in the light, maybe the high level of CFP is producing enough
free
>radicals to affect growth. If this was the problem, the CFP should not
affect
>the pollen tubes in the dark.
>-=Paul=-
Thanks for this comment!
The pollen tubes were actually kept in the dark starting right after
particle bombardment until observation under the microscope. So, the
suggested explanation appears unlikely.
I wonder whether the CFP toxicity we find in pollen tubes may
have something to do with the observation made by Heim et al. (1994, PNAS
9,12501) that GFP carrying the Y66W mutation (which is responsible for CFP's
fluo characteristics) is only inefficiently expressed in E. coli (in
contrast
to other GFP versions). Could it be that the protein has a stability
problem, and that accumulating missfolded CFP can interfere with essential
cellular functions?
Benedikt
