|
|
Line 3: |
Line 3: |
| {{Team:Amsterdam/Header}} | | {{Team:Amsterdam/Header}} |
| {{Team:Amsterdam/Sidebar1}} | | {{Team:Amsterdam/Sidebar1}} |
- | <html>
| |
| <div id="main-content"> | | <div id="main-content"> |
- | <p><b>Introduction</b><br>
| |
- | Prokaryotes have been selected through evolutionary processes for accurate sensing
| |
- | and acting upon their living environments. This bacterial versatility can be used by
| |
- | us, humans, to sense the environments in places we have trouble reaching. Maybe we
| |
- | would want to measure the conditions (e.g. nutrient availability, toxicity, pathogen
| |
- | presence, light) somewhere deep under the ground, perhaps we would want to noninvasively
| |
- | scan for biomarkers in diseased tissue in our bodies. The classical way
| |
- | to make a bacteria tell us whether a certain event has happened is to link it to the
| |
- | transcription of fluorescent proteins. This however requires constant monitoring and
| |
- | maintenance in order to get an idea of the time-variation of the studied system. Could
| |
- | we make the cell ‘remember’ what it has sensed and when so we can leave it alone for a
| |
- | while and make it report back to us later?<br><br>
| |
- |
| |
- | Meet <b>'Me C0l1'</b>, a methylation based celullar log, which uses the naturally occurring phenomenon
| |
- | of <b>DNA methylation</b> to robustly store signals it has sensed in its environment. The
| |
- | Amsterdam iGEM 2012 team, consisting of six students, will dedicate the summer to
| |
- | the realization of this innovative and ambitious plan. This novel storage mechanism,
| |
- | redesignating an evolutionarly designed tested and proven principle for novel purposes,
| |
- | could be linked to any of the many biological sensors that are available in the DNA
| |
- | parts registry. E. memo therefore holds great promise as a detect & store–system for
| |
- | experimental and industrial purposes.<br><br>
| |
- |
| |
- | Just storing whether certain signals have been sensed by the cell is only half of the story
| |
- | however. The proposed memory mechanism would be a form of volatile memory,
| |
- | of which the traces slowly dissappear as the E. memo-population keeps proliferating.
| |
- | This is because methylation-patterns are not transferred to the progeny in eukaryotes.
| |
- | We can use this our advantage. The most exciting part of our project would be to infer
| |
- | when a signal has been sensed from the percentage of bits that is methylated, which
| |
- | slowly decreases as the cells keep proliferating. This way, we won’t just store whether
| |
- | a certain signal has occured; we will also know when it happened.<br><br>
| |
- |
| |
- | <b>Molecular mechanism</b><br>
| |
- | In short, we will introduce a site-specific methyltransferase into the iGEM default
| |
- | chassis organism E. coli, that will only be active/transcribed when the measured signal
| |
- | is encountered by the logbook-cell. The activated methyltransferase will then move
| |
- | over to a plasmid region we’ve termed the bit and append a methyl-group to it. By
| |
- | 1
| |
- | linking the methyltransferase to a Zinc-Finger, its site-specificity is greatly increased,
| |
- | reducing the amount of undesired background methylation events to a minimum.
| |
- | Furthermore, by slowing down the cell replication cycle of the cells, we can increase
| |
- | the span of time we can use to do measurements on.</p>
| |
| </div> | | </div> |
- | </html>
| |
| {{Team:Amsterdam/Foot}} | | {{Team:Amsterdam/Foot}} |