Difference between revisions of "Part:BBa K1104202"

Revision as of 12:35, 2 October 2013

HemH promoter

Introduction

HemHp promoter is controlled by OxyR (transcription factor), which is activated by ROS(Reactive Oxygen Species). An intramolecular disulfide bond between Cys199 and Cys208 will form in an OxyR transcription factor, and active OxyR molecule will bind to the binding site of HemHp, making the following circuit turned on.

In our project: Bee. coli, we use HemH as the sensor of Bee. coli to sense Nosema ceranae. After Nosema ceranae enter bees' midgut, the natural immune reaction will lead to ROS released by epithelia of bees' midgut. We select several promoters that can be induced by OxyR(Part:BBa_K1104200), which is activated by ROS. One of these promoters is HemHp.

OxyR is activator of ahpC promoter and its improvement parts. More details about OxyR can be found on the PartRegistry page: Part:BBa_K1104200.

HemHp

Information of HemHp on [http://www.ecocyc.org/ECOLI/NEW-IMAGE?type=OPERON&object=TU0-3104 Ecocyc]

We get information of HemHp from [http://www.ecocyc.org/ECOLI/NEW-IMAGE?type=OPERON&object=TU0-3104 Ecocyc],

HemHp is regulated by σ70, and there are two TFBSs upstream for OxyR. We also did some literature study, according to the citation.

In E. coli genome, thioredoxin(trxC) will express in response to elevated H₂O₂ level. Expression of genes encoding thioredoxin(trxC) is regulated by OxyR. Oxidized OxyR binds directly to HemHp and induce its expression.

Schematic drawing of the HemH regulon in E. coli K12 (taken from [http://www.ecocyc.org/ECOLI/NEW-IMAGE?type=OPERON&object=TU0-3104 Ecocyc])

Nucleotide Sequence of HemHp(taken from [http://www.ecocyc.org/ECOLI/NEW-IMAGE?type=OPERON&object=TU0-3104 Ecocyc])

OxyR TFBS1 Sequence of HemHp(taken from [http://www.ecocyc.org/ECOLI/NEW-IMAGE?type=OPERON&object=TU0-3104 Ecocyc])

OxyR TFBS2 Sequence of HemHp(taken from [http://www.ecocyc.org/ECOLI/NEW-IMAGE?type=OPERON&object=TU0-3104 Ecocyc])

_{Reference: Ritz, D. (January 28, 2000). Thioredoxin 2 Is Involved in the Oxidative Stress Response in Escherichia coli. Journal of Biological Chemistry, 275, 4, 2505-2512.}

Usage and Biology

We designed circuit fighting against Nosema ceranae. After Nosema ceranae infected midgut cells of bees, and Bee. coli should sense the pathogen first before the following circuit(fighting against Nosema ceranae)is triggered, and substance such as Defensin(Part:BBa_K1104300), Abaesin(Part:BBa_K1104301) (more details on [http://2013.igem.org/Team:NYMU-Taipei/Project/Inhibition/Killing Killing Nosema] page) in the following circuit will express.

Besides, in order to enhance the strength of HemHp, we added a device (more details on [http://2013.igem.org/Team:NYMU-Taipei/Project/Inhibition/Sensor Sensing Nosema] page).

HemHp-strenthening device

Related Parts

1. Part:BBa_K1104242: HemHp+E0840, reporter with GFP for promoter testing.
2. Part:BBa_K1104202: HemHp, another OxyR-induced promoter.

Sequence and Features