| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1992: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1991: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1990: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
How do bacterial cells use information about their surroundings to make appropriate adaptive responses? In its simplest, a two-component regulatory system consists of a membrane receptor and a cytoplasmic DNA-binding protein. Environmental information gathered by the receptor is passed to the DNA-binding protein (regulatory protein) via phosphorylation. This modification changes the properties of the regulatory protein, resulting in an alteration in gene expression. One hint that cross-talk can occur in vivo is also suggested by the fact that expression or overproduction of the regulator proteins NtrC, OmprR DctD, CheY, OgtA, FixJ and PhoR in the absence of their sensor partners, elicits a target response that, in most cases, is consitutive. In this report, we present a new two component system isolated using such a cross-talk in vivo. This success also suggests that the network of bacterial signal transduction via cross-talk should be profound.
The 1864 uncleotide sequences containing
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the essential region, which is located at 51 min.on E. coli chromosome and regulates ompC expression, were determined. In this region, two open reading frame were present. These results suggest that ORF1 and 2 constitutes the typical two component system and the ORF1 and ORF2 were tentatively named EvgA and EvgS, respectively. The protein products of EvgA and EvgS, predicted from their DNA sequences were in fact detected by in vitro coupled transcription translation system. These deduced molecular weights of EvgA and EvgS were well consistent with BvgA and BvgS (23kDa,135kDa).
It is well known that the virulence gene of Bordetella pertussis is repressed by 28ﾟC, MgSO_4 or nicotinic acid via BvgA and BvgS. The effects of such environmental factors on ompC expression via EvgA and EvgS were investigated. In RU1012 containing pSK001, ompC-expression was repressed by 28ﾟC, MgSO_4 or nicotinic acid.
In this paper, we have succeeded in cloning two new component regulatory genes which is based on the idea that in vivo cross-talk can actually work, This cloning strategy was confirmed to be effective in isolating the two component regulatory genes involved in environmental responsive system. Clearly structural homology also indicates that EvgA and EvgS can work as a signal transduction system similar to the EnvZ-OmpR two component system. Taken together, these evidences described here strongly support that in vivo cross-talk could work between OmpR/EnvZ and EvgA/EvgS. Less
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