[Dioxin-l] molecular mechanism of dioxin action

[david bell]

Dear Jon
you can read the abstract as well as I can.
Nonetheless, you appear to have misread it, or to be reading other papers of 
which I am unaware. The data of Roberts, Pollenz, et al., show that the 
activated AhR is rapidly degraded- ie is removed from the nucleus. I have 
seen no data that the further activation of cytoplasmic AhR by dioxin is in 
any way impaired.

These papers do not address your other statement- that transcription 
initiated by dioxin continues- but the disappearance of AhR from the nucleus 
suggests that the converse is true. However, it is quite clear, that in the 
presence of sufficient dioxin, there is consistent gene activation; this 
must be achieved by some balance between receptor degradation and receptor 
synthesis.

best wishes
david


<snip>
>
>      It appears that the Ah receptor, but not the ARNT, is degraded, that
>the transcription initiated by the presence of dioxin in the nucleus
>continues, and that the mechanism you are describing appears to merely
>curtail further transmission of other dioxin molecules into the nucleus.
>
>      Is this a correct interpretation?
>
>Thanks
>Jon

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