Jun 24, 2009 image
In an abstract form (top), a biological memory device includes two elements:
- A ‘trigger’ that senses an external stimulus; and
- A ‘memory loop’ that is turned on by the trigger and then turns itself on.
These elements are constructed as large pieces of DNA that include promoter regions and segments that code for proteins. These DNAs are essentially mash-ups (technically termed fusions or chimeras) – bits and pieces of natural DNAs from different sources that have been combined in new ways to have new properties of human design. For example, the specific trigger module shown here consists of a promoter from yeast and coding segments for a fluorescent protein from a jellyfish, a DNA-binding protein from a bacterium, a transcription activator from a mammalian virus, and a nuclear localization signal from a different virus. The protein coding segments are joined to make a single fusion protein with properties combining all of the components. (Credit: Silver lab)