Re: [DIYbio] Current patents on GFP, RFP, and bioluminescence

I imagine that the lac operon was discovered long before GFP, and
therefore the lacZ complementation system, though far more awkward and
boring, is public-domain by now.

If you're not familiar with it, lacZ complementation works like this:
LacZ is a protein that digests lactose into Galactose and Glucose. It
can be artificially induced (gene activation) by an artificial chemical
called IPTG, and it digests not only lactose but a bunch of artificial
pro-dyes such as X-gal, giving them a vivid colour upon digestion.

LacZ is knocked out in loads of lab strains of E.coli (don't assume;
check your strain!), so that you can use a plasmid containing a
functional LacZ gene and use it to detect transformants by plating them
on X-gal under conditions that activate your artificial LacZ gene.
Transformed cells will turn dark blue as they digest the pro-dye into a
vivid blue dye.

Because most cloning methods use antibiotic resistance and therefore
don't need colours to detect likely transformants, it's common enough
for plasmids to contain LacZ with a cloning site in the middle of it, so
that if you successfully get your desired new DNA into the plasmid and
deliver this to the cell, your desired transformants will be colourless
instead. In this case, blue cells represent those that were transformed
with an "empty" plasmid without your desired DNA, whereas the colourless
ones (presumably) contain the DNA you tried to clone into the plasmid
prior to transformation.

Of course, the problem with LacZ is that it requires X-gal.

I imagine there are other dyes and colours you can get a cell to produce
besides GFP that were discovered first, but GFP was always more popular
because you can do long exposures to detect invisibly small amounts of
GFP, so it's easy to detect, and easy to compare for relative
expression. I recall detecting a few bacillus pigments in the literature
when designing a B.subtilis plasmid, but I ignored them because they've
been reclassified into different species since discovery, and I was
constraining the design to B.subtilis-only DNA for regulatory reasons...

On 27/01/13 23:54, Koeng wrote:
> My real question is is there any marker that are open sourced yet? It
> would be great if there was :)
>
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