Team:SMTexas/Design

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<h4> XylR Gene (Detects Xylene) </h4>
<h4> XylR Gene (Detects Xylene) </h4>
The genetically-related expression of the XylR gene consists of many steps and parts, including promoters, regulator complexes, and proteins. The first part is the Pr promoter, which promotes the coding DNA sequence for the XylR gene itself. Following that, there is the ribosomal binding site portion of the sequence, which ensures that translation is initiated and that it occurs in the right place. Directly after this RBS is the exon itself, which naturally expresses the XylR protein, important to the E. Coli cell. Because this protein triggers a secondary response in the bacterium which is vital to Xylene detection, a double termination sequence is need to ensure that anything downstream of the XylR coding region is not expressed, potentially disrupting the reactions involved in the detection system. These stop codons, although short, are effective in terminating the expression of the sequence. The XylR protein that was created, given the that xylene is present in the bacterium, reacts with the VOC and becomes conformed. This newly conformed version of the protein can bind to the Pu promoter, which is part of an entirely different sequence. After a second ribosomal binding site (strong) is used after the promoter and YFP is placed directly after this RBS.1, the bacteria will grow green in the presence of xylene.  
The genetically-related expression of the XylR gene consists of many steps and parts, including promoters, regulator complexes, and proteins. The first part is the Pr promoter, which promotes the coding DNA sequence for the XylR gene itself. Following that, there is the ribosomal binding site portion of the sequence, which ensures that translation is initiated and that it occurs in the right place. Directly after this RBS is the exon itself, which naturally expresses the XylR protein, important to the E. Coli cell. Because this protein triggers a secondary response in the bacterium which is vital to Xylene detection, a double termination sequence is need to ensure that anything downstream of the XylR coding region is not expressed, potentially disrupting the reactions involved in the detection system. These stop codons, although short, are effective in terminating the expression of the sequence. The XylR protein that was created, given the that xylene is present in the bacterium, reacts with the VOC and becomes conformed. This newly conformed version of the protein can bind to the Pu promoter, which is part of an entirely different sequence. After a second ribosomal binding site (strong) is used after the promoter and YFP is placed directly after this RBS.1, the bacteria will grow green in the presence of xylene.  
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<table><tr><td width="1200" align="center"><img src="https://static.igem.org/mediawiki/2014hs/a/a5/XylR_Map.png"></td></tr></table>  
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<table><tr><td width="1200" align="center"><img src="https://static.igem.org/mediawiki/2014hs/a/a5/XylR_Map.png"></td></tr></table>
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<h5>frmR Gene</h5>
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The frmR gene is induced by formaldehyde, a VOC that exists in higher concentrations in the breath of lung cancer patients.  In E. Coli, frmR is followed by a promoter, which in turn is followed by an operator and the GFP coding gene. frmR, which functions as a regulatory gene, codes for a protein which acts as an active repressor for the operator.  Thus, RNA polymerase cannot pass through the operator and transcribe GFP. Formaldehyde, which acts as a co-repressor, would bind to the protein and conform it into an inactive shape, allowing the RNA polymerase to pass through the operator and transcribe the GFP protein.  Thus, if formaldehyde is present, the GFP gene is expressed, and the bacteria will glow in the presence of the VOC.
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Revision as of 15:12, 11 June 2014