Team:Harvard/Parts/Other

From 2008.igem.org

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=lacI Inducible System=
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=Our other parts=
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==TetR-based Inducible System==
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In this system, the lac repressor (LacI) is controlled by a strong constitutive promoter, and is upstream of mtrB under the control of pLac, a LacI regulated promoter. In the default state, LacI is expressed, and inhibits transcription at pLac. Thus, in the default state, mtrB is not expressed. IPTG (an analog of allolactose) induces mtrB expression by binding to LacI, thereby preventing it from inhibiting transcription at pLac.
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The TetR system we hoped to develop would have been similar to the lacI system. The pTet promoter which controls mtrB expression is regulated by the repressor TetR ([http://partsregistry.org/wiki/index.php?title=Part:BBa_C0040| BBa_C0040]). Expression of mtrB would have occurred when the system is induced with anhydrotetracycline which binds TetR. Unfortunately, as mtrB is toxic, we could not clone successful clone this system.
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<div style="text-indent:0pt;color:black">[[Image:BBa_K098984.png|thumb|650px|center|BBa_K098984 with BioBrick Prefix and Suffix]]</div>
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==Inducibility Test for Lac System with GFP Reporter and Weak Promoter==
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An induction test was designed to test the inducibility of the lac system by IPTG when the repressor (LacI) is driven by a weak promoter.
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===Method===
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<div style="text-indent:0pt;color:black">[[Image:Lac.png|thumb|150px|Click for diagram of induction experimental method]]</div><br>
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Starter cultures of E. coli with [http://partsregistry.org/wiki/index.php?title=Part:BBa_K098982| BBa_K098982] were grown overnight.  They were then diluted and grown to OD 0.2 before separation into induced (+IPTG, 1mM) and uninduced cultures (-IPTG). OD and GFP readings were taken at time 0, 2, and 4 hours.  Additionally, after diluting T=2hrs samples to OD 0.2 for accurate GFP measurements, samples were further diluted 1000x, induced (or not induced) again, and placed back in the incubator until the end of the experiment, when OD and GFP readings were taken.
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===Results===
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Induction of GFP expression was observed at both 2 and 4 hours after adding IPTG.  Levels of GFP expression in uninduced samples, however, remained relatively the same throughout the 4 hours.  Meanwhile, IPTG induction was not observed in either the negative control ([http://partsregistry.org/wiki/index.php?title=Part:BBa_K098981| BBa_K098981]) or the constitutive GFP control ([http://partsregistry.org/wiki/index.php?title=Part:BBa_K098991| BBa_K098991]).
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PDF version: [https://static.igem.org/mediawiki/2008/c/ce/CIts_system.pdf]
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<div style="text-indent:0pt;color:black">[[Image:Lac.jpg|720px|thumb|center|Lac Inducibility Results]]</div>
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The 1000x dilutions of samples at 2 hours after induction produced similar results after 5-6 hours.  These cells are presumably at a different growth phase from cells that have been growing at much higher concentration for longer, and are thus induced in different conditions.
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<div style="text-indent:0pt;color:black">[[Image:Lac1000.jpg|720px|thumb|center|Lac Inducibility 1000x Results]]
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However, we did submit parts [http://partsregistry.org/wiki/index.php?title=Part:BBa_K098980 BBa_K098980] and [http://partsregistry.org/wiki/index.php?title=Part:BBa_K098981 BBa_K098981] in case you might find them useful.
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==Light-induced System==
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We tried to create a light-induced mtrB expression system using the [http://partsregistry.org/Featured_Parts:Light_Sensor light sensor] in the registry. This requires an EnvZ deficient strain of ''S. oneidensis'' which we could not successfully generate. Additionally, the registry versions of some of the parts appear wrong (in sequence) or nonfunctional. We thus provide the following two parts for future teams' use:
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*[http://partsregistry.org/wiki/index.php?title=Part:BBa_K098011 ''E. coli'' ompR for introduction into other species of bacteria]
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*[http://partsregistry.org/wiki/index.php?title=Part:BBa_K098010 A HO-pcyA protein generator]
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Latest revision as of 04:51, 30 October 2008



Our other parts

TetR-based Inducible System

The TetR system we hoped to develop would have been similar to the lacI system. The pTet promoter which controls mtrB expression is regulated by the repressor TetR (BBa_C0040). Expression of mtrB would have occurred when the system is induced with anhydrotetracycline which binds TetR. Unfortunately, as mtrB is toxic, we could not clone successful clone this system.

However, we did submit parts BBa_K098980 and BBa_K098981 in case you might find them useful.

Light-induced System

We tried to create a light-induced mtrB expression system using the light sensor in the registry. This requires an EnvZ deficient strain of S. oneidensis which we could not successfully generate. Additionally, the registry versions of some of the parts appear wrong (in sequence) or nonfunctional. We thus provide the following two parts for future teams' use: