The Legend

"It all began with the forming of the magic Coli rings. Three were given to the eleven Coli Kings, noblest and fairest of all Coli-beings. Seven were given to the dwarf Colis, great miners who live in there Halls of Agar. And nine, nine rings were given to Mortal Colis, who above all desire power. But they were all of them deceived, for the Dark Coli Lord in secret formed a master Coli ring! One ring rule them all. One by one the Colis fell into the control of Dark Coli Lord. But there were some who resisted it. In a great battle the Dark Coli Lord was ultimately defeated and the Coli rings were lost. Time passes by, history becomes legend, legend becomes myth. When the master Coli ring had passed out from almost all knowledge, it was then picked up by someone who the Colis would never have expected: a group of human from HKU!
The Coli ring itself was a book of history. In it the human learnt about the great Coli rings of the past and that great battle which had already faded into the years and nowhere else be found. It was said that those who are able to collect the entire set of magic Coli rings can fulfill any hopes that they wish. Influenced by the magic of the master Coli ring, the human and his fellow set out to search for the rest magic Coli rings…… "

(Modified from script of The Lord of the Rings: The Fellowship of the Ring)

Abstract

The ability of living organisms to form patterns is an untapped resource for synthetic biology. The HKU iGEM2008 team aims to generate unique patterns by rewiring the genetic circuitry controlling cell motility. Specifically, E. coli cells are programmed to autonomously regulate their movement by sensing local cell density. Interesting patterns are formed by two types of newly engineered cells. The high cell-density motility-off cells spread outwards and spontaneously form a distinctive ring of low cell density surrounded by rings of high cell density whilst the high cell-density motility-on cells form a Fuji-mountain-like structure. Moreover, we build a theoretical model that satisfactorily fits our current experimental data, and also predicts some parameters which may significantly affect the ring formation. The study of this self-organized spatial distribution of cells helps us to understand principles underlying the formation of natural biological patterns, and synthetic non-natural patterns have various potential applied uses

Overview

iGEM2008 iHKU team aims to deliver you the most brilliant project this year. We come from departments of Biochemistry, Bioinformatics, Physics, and Chemistry. With different backgrounds and modalities of thought, we complement each other in developing new ideas, and in following wet/dry lab work (Team).
Pattern formation is one of the most common yet fascinating biological phenomena happening in our daily lives, though for centuries, biologists, physicists and mathematicians have struggled to understand its nature. How do highly ordered patterns arise from a few living cells? How can our hands, our eyes, our bones form their shape with such an extremely low mistake rate? This question is fascinating but crucial. Bacteria use their flagella to move around. To generate a recognizable and stable pattern, bacterial motility must be controlled and coordinated. This can be accomplished by designing a genetic circuits coupling bacterial quorum sensing system and genes controlling mobility. There are several key genes responsible for the movement of flagella, two of them are cheY and cheZ. CheY protein has two forms: its phosphorylated form makes flagella rotate clockwise and the cell will tumble; its dephosphorylated form makes flagella rotate counterclockwise and the cell will be driven straight in one direction (run). CheZ protein can help the progress of dephosphorylation of protein cheY.
By rewiring the genetic circuitry controlling cell motility, we aim to generate unique patterns (Design). First, we applied the method of Recombineering to delete cheZ gene in chromosome of wild type E.coli strain, MG1655 (Protocols). And then, a series of biobricks and strains were successfully constructed (Plasmids and strains). As expected, fantastic patterns were fortunately observed (Results), including Fuji-mount like and ring-like pattern. Since the ring-like pattern is so charming, our rest work mainly focused on the characterization and modeling of this pattern. The modeling…. (Modeling). Modeling and experimental data indicated some factors might significantly affect the development of ring-like pattern. By measuring these factors, we provided not only solid data to support our hypothesis of modeling, but values of parameters to maturate it (Results).? As a result, it’s surprising that we achieve two-ring pattern by slightly tuning the genetic circuitry (Results).
During the experiments, we have encountered uncountable difficulties. To overcame them, we have created several NOVEL protocols, software, and devices with the help of our knowledge from different fields, such as “growth curve on agar plate” (Protocols ), “movie taker” , and “reflection spectrophotometer” (Novel devices). We believe more researchers will benefit from our inventions.
Last but not least, in this project, we created 15 biobricks and characterized 1 existed biobrick (Characterization), which are considered to be helpful to coming iGEM competitions and the study of synthetic biology.
Everybody of us cherish this invaluable opportunity to work together to improve communication and complementarity, and finally to fulfill our dream in iGEM2008!