| The human circadian rhythm drives many important processes in the body in accordance with the sleep/wake cycle. A characteristic of this biological clock is the periodic oscillation of gene expression. Current parts in the Registry designed to regulate periodic oscillations of gene expression have shown limited success.
Here we demonstrate a biological clock being standardised as a set of BioBrick parts. Our network is controlled by an engineered promoter, Plac/ara, which features both an activator and a repressor domain. This controls the production of downstream genes to activate other inducible promoters, pBAD and GlnAp2, eventually leading to the production of a repressor protein, lacI, which inhibits Plac/ara, resulting in oscillatory expression. This project shows the feasibility of standardising the biological clock in E. coli and grounds further development for applications in regulated drug/hormone delivery and ion channel control. | 
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| Plac/ara
A multi-domain promoter that is self-inducible by arabinose. Gene expression regulated by LacI binding to special operator sites in the promoter | 125x125px | glnG
Encodes for DNA-binding protein(NR1), the activity of which depends on its phosphorylation. Drives expression of genes under GlnAp2 promoter |
| 125x125px | araC
Encodes for a positive regulatory protein for L-arabinose utilization in E.coli | 125x125px | pBAD
L-arabinose inducible promoter |
| 125x125px | LacI
DNA-binding transcriptional inhibitor for lac-operon | File:Promoter image 2011.png | GlnAp2
Promoter driven by phosphorylated GlnG(NR1) |
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