Gating functions in protein networks

Dan dmb at
Fri Aug 1 04:22:19 EST 2003

Lord Snooty wrote:
> "Gordon D. Pusch" wrote:
>>Dan <dmb at> writes:
>>>I think you can generate all logical functions using
>>>just a simple combination of lesser functions, but I
>>>forget which.
>>NAND (NOT(a AND b)) will work. Also NOR (NOT(A OR b)).  Also the
>>"Sheffer stroke," <>.
>>There are several other possibilities. To build a NOR gate,
>>insert two or more dissimilar repressor binding sites in between
>>its promotor binding site and the gene; if a repressor protein
>>binds to any of them, it shuts off transcription of the gene.
>>(Of course, the boolean response will be "softened" due to chemical
>>kinetics, but that's just a fact of life --- in both senses of the phrase! :-/)
>>-- Gordon D. Pusch
>>perl -e '$_ = "gdpusch\\n"; s/NO\.//; s/SPAM\.//; print;'
> Thanks! This is exactly the kind of information I'm looking for. You've described a
> plausible physical model for implementation of a NOR gate. My only follow-up
> question would be whether we in fact observe this in specific instances, for any
> known genes?

Do you mean one gene with two separate negative control mechanisms?
(sorry I am not sure what NOR is)


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