Oxygen Control System: PrrA/PrrB two

component regulation system!

This regulatory system is able to sense oxygen concentration and send a response, under high oxygen tension, the system remains inactive, when oxygen concentration decreases PrrB (Histidine sensor kinase) turns active through an autophosphorylation with help of PrrC, which receive the signal from electron transport chain. Then PrrB transfer a phosphate group to PrrA that directly binds promoter and recruits RNA polymerase to start GFP transcription. (See the next video for a visual explanation).

Our biobricks

The first biobrick consists in the complete oxygen dependent system, PrrA, PrrB and PrrC, each one with a Ribosome Binding Site, under a Medium strength promoter (J23104), this first biobrick also it has the PrrA dependent promoter and GFP as a reporter gene

The second biobrick is just the PrrA dependent promoter and GFP as a reporter gene.

We were inspired in:

This system is inspired in PrrBCA two component system from R. sphaeroides, which is a master regulator involved in expression of approximately 850 genes, >20% of the genome (Kaplan & Eraso 2005) This system coordinately controls genes involved in the complex switch between aerobic and anaerobic conditions and the optimum use of reducing power. It also regulates gene expression involved in photosynthesis, carbon dioxide fixation, nitrogen fixation, hydrogen uptake, aerotaxis, denitrification, electron transport, aerobic and anaerobic respiration, and heme biosynthesis, and others. Thus emphasizing its global role (Elsen et.al 2004, Kaplan & Eraso 2005, Zeilstra-Ryalls & Kaplan 2004).

References
1. Kaplan S, Eraso J, Roh JH. (2005). Interacting regulatory networks in the facultative photosynthetic bacterium, Rhodobacter sphaeroides 2.4.1. Biochem. Soc. Trans. 33:51–55
2. Zeilstra-Ryalls JH, Kaplan S. (2004). Oxygen intervention in the regulation of gene xpression: the photosynthetic bacterial paradigm. Cell. Mol. Life Sci. 61:417–36
3. Eraso JM, Kaplan S (2009) Regulation of gene expression by PrrA in Rhodobacter sphaeroides 2.4.1: role of polyamines and DNA topology. J Bacteriol 2009, 191(13):4341-4352.