Field of Science

Creating Biobricks

One of the main features of synthetic biology is that it should work very much like Lego. Genes are acquired from a standard registry, and can be introduced into bacteria in the form of plasmids (small autonomously replicating sections of DNA). The genes are in a standard format, connected to standard 'prefix' and 'suffix' sections (which contain restriction sites - cut and paste DNA sections that connect everything together, most specifically connect the gene to the plasmid).
The BioBrick part (shown bracketed in blue) contains the actual gene. In my case, the gene for the brown pigment melanin. The little circles on either side are restriction sites, enzymes can cut the DNA at these places, allowing the BioBricks to be moved around and, if necessary, stuck together. The red brackets show the plasmid. The purple square labelled 'origin' is the origin of replication, allowing the plasmid to be copied within the bacterial cell. The green 'antibiotic resistance' box is a marker, to check whether the plasmid has entered the cell. The plasmids are put into the bacteria in a process called transformation, after which the bacteria are plated out onto antibiotic plates. Only those which contain the plasmid are able to survive.

It works well on paper. And it seems to work quite well in real life. There is even a registry of standard BioBrick parts, you can order them and mix them together to form biological engineering systems. They tend to work as well, with varying degrees of success, and if all goes well hopefully my little brown pigment plasmid will be in there as well one day. All I have to do is cut the gene out of the plasmid it's currently in, remove unwanted restriction sites, and stick it into the red-bracketed plasmid shown above.

This can all be done by PCR =D

(If I get totally stuck with it, the other option is just to get the gene synthesised and stick it straight into the plasmid. Easier...but more expensive)


Toby said...

How do you produce the BioBrick in the first place? Do you just get millions of the plasmids and then cut out the BioBrick?

Or can you synthesis them from scratch?

Lab Rat said...

The BioBrick vector is a pretty standard vector that has just been modified a little. You can get the registry to send them too you.

The actual gene can be taken from anywhere. You can either splice them out of genomes or other plasmids or get them synthesised. Synthesis is becoming more and more common as it gets cheeper.