=== <span style="color:#D4A017">Motivation and Background</span> ===
=== <span style="color:#D4A017">Motivation and Background</span> ===
-
In humans, the circadian rhythm is controlled by several core genes that operate via a series of feedback loops (Figure 1). A transcription–translation negative-feedback loop powers the system, with a delay between the transcription of these genes and the negative feedback being a key factor that allows the system to oscillate [1]
+
In humans, the circadian rhythm is controlled by several core genes that operate via a series of feedback loops (Figure 1). A transcription–translation negative-feedback loop powers the system, with a delay between the transcription of these genes and the negative feedback being a key factor that allows the system to oscillate [1]. A 'master clock' located in the Suprachiasmatic Nucleus coordinates the timing of the rhythm, but external factors such as light exposure play a large role in regulating the exact
+
<b>Figure 1: The gene network responsible for establishing the circadian rhythm in humans [1]</b>
<b>Figure 1: The gene network responsible for establishing the circadian rhythm in humans [1]</b>
[[File:Mammalian.png]]
[[File:Mammalian.png]]
+
+
+
There has been much effort put into reconstructing and determining the exact nature of this system, as the impact the circadian rhythm has on our lifestyle and cellular processes are still not very well understood. In particular, it is believed the circadian rhythm could exert an effect on everything from body temperature, feeding behaviour and appetite, hormone secretion and metabolism, glucose homeostasis, and cell-cycle progression [2].
[1] Gallego, M & Virshup, DM 2007. "Post-translational modifications regulate the ticking of the circadian clock", <i>Molecular Cell Biology</i>, vol. 8, pp. 139-148.
[1] Gallego, M & Virshup, DM 2007. "Post-translational modifications regulate the ticking of the circadian clock", <i>Molecular Cell Biology</i>, vol. 8, pp. 139-148.
+
+
[2] Takahashi, JS, Hong, HK, Ko, CH & McDearmon, EL 2008. "The genetics of mammalian circadian order and disorder: implications for physiology and disease", <i>Genetics</i>, vol. 9, pp. 764-775.
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.
Project Details
The project has been split into categories:
Development of BioBricks
Experimental methods to be fully recorded in the Notebook
Modelling of the circuit
Modelling of the kinetics of the oscillating cells
Modelling of the synchronisation of oscillating cells
Thorough evaluation of the safety issues regarding UQ-Autralia's entry in iGEM
Human practices
Raising awareness of synthetic biology
Providing a solution to the patenting issue that iGEM is facing
Together, this forms the UQ-Australia project for the 2011 iGEM.
Motivation and Background
In humans, the circadian rhythm is controlled by several core genes that operate via a series of feedback loops (Figure 1). A transcription–translation negative-feedback loop powers the system, with a delay between the transcription of these genes and the negative feedback being a key factor that allows the system to oscillate [1]. A 'master clock' located in the Suprachiasmatic Nucleus coordinates the timing of the rhythm, but external factors such as light exposure play a large role in regulating the exact
Figure 1: The gene network responsible for establishing the circadian rhythm in humans [1]
There has been much effort put into reconstructing and determining the exact nature of this system, as the impact the circadian rhythm has on our lifestyle and cellular processes are still not very well understood. In particular, it is believed the circadian rhythm could exert an effect on everything from body temperature, feeding behaviour and appetite, hormone secretion and metabolism, glucose homeostasis, and cell-cycle progression [2].
[1] Gallego, M & Virshup, DM 2007. "Post-translational modifications regulate the ticking of the circadian clock", Molecular Cell Biology, vol. 8, pp. 139-148.
[2] Takahashi, JS, Hong, HK, Ko, CH & McDearmon, EL 2008. "The genetics of mammalian circadian order and disorder: implications for physiology and disease", Genetics, vol. 9, pp. 764-775.
"
