From 2006.igem.org

Revision as of 08:11, 19 September 2005

Organisational

Group Members

• Christophe, Dominic (coordinator), Giorgia, Herve, Zlatko

Group Meeting History

log 2005-08-17: Wednesday, 13:00 @ polyterrasse: Discussion of module, next steps, task distrib.
log 2005-08-22: Monday, 15:00 @ polyterrasse: Discussion of biol. solutions.
log 2005-09-12: Thursday, 17:30 @ teammeeting.

Input-module Development

Introduction

The iGEM-team at ETH decided to implement a modular and standardized Counter-system that can in principle be used to count any kind of biological event and generate any kind of output after a certain number N of events has been detected. The Counter-system can be split into 2 basic units, the NOR-module and the INPUT-module (outlined in red in the schematic below). This document deals with the implementation of the INPUT-module.

Purpose of the INPUT-module

In a nutshell, the Input module has 2 system boundaries, both of which are characterized by PoPS (Polymerase Per Second). Its purpose is to take a single input PoPS and output 2 different PoPS. One of the outputs should be high and the other low when S is high and vice versa when S is low.

     PoPS_outn
         ^
         ¦
 high    ¦ PoPS_out2 _______           _________ PoPS_out1
         ¦                  \         /
         ¦                   \       /
         ¦                    \     /
         ¦                     \   /
         ¦                      \ /
         ¦                       X
         ¦                      / \
         ¦                     /   \
         ¦                    /     \
         ¦                   /       \
 low     ¦ PoPS_out1 _______/         \_________ PoPS_out2
         ¦--------------------------------------------------> PoPS_in, t
         0                                               1

Input-module Schematic

Below a preliminary parts-view of the module, i.e. encapsulation of biological specific implementations into a functional box with general PoPS interfaces.

With this design, any input can be used, as long as a romoter can be found that is either activated or suppressed by it. At the output any kind of genes can be added which will be produced depending on the PoPS of that particular input.

legend: 
I:         input signal that will bind to the promotor P_in, e.g. heat shock dependent etc.
P_in:      promotor that allows the signal of choice I to bind.
PoPS_in:   polymerase per second dependent on promotor and concentration of I
Reg:       regulation genes. there are different solutions possible, see below.
r:         repressing signal. highly dependent on Reg, P_r and of course speed and binding considerations
a:         activating signal. highly dependent on Reg, P_a and of course speed and binding considerations
rep:       repression, indicated by horizontal bar
act:       activation, indicated by arrow
P_r:       promotor region to be repressed and/or "roadblock" region. constitutively active
P_a:       promotor region to be activated and/or "roadblock" region. not constitutively active
PoPS_out1: polymerase per second dependent on P_r and r.
PoPS_out2: polymerase per second dependent on P_a and a.
R_n:       toggle switch gene(s)

Suitable Strategies

As shown in the black box above, the core of the device is a regulator sub-module, for which different implementation strategies have been investigated.

We identified various solutions, the remaining ones being

• The λ-system with two variants
  • The original anti-parallel version
  • An engineered unidirectional version
• The Lux-system

To be continued: [http://www.ek.ethz.ch/iGEM/Input-module.planning.050905.doc input-module docu as word document] for now (maintained by dominic). Details of the literature research on the two strategies above should be extended by Christophe and Hervé themselves