Assessment of tfdR and tfdS Promoter Activity of 2,4-Dichlorophenoxyacetic Acid

EPA Grant Number: MA916288
Title: Assessment of tfdR and tfdS Promoter Activity of 2,4-Dichlorophenoxyacetic Acid
Investigators: Davison, Michelle
Institution: California State University - Fresno
EPA Project Officer: Zambrana, Jose
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $88,478
RFA: GRO Fellowships for Graduate Environmental Study (2004) RFA Text |  Recipients Lists
Research Category: Academic Fellowships , Fellowship - Environmental Science/Forensic Science , Ecological Indicators/Assessment/Restoration


The objective of this research project is to investigate expression from the promoter regions of tfdR and tfdS coding for the regulatory proteins of the 2,4-dichlorophenoxyacetic acid (2,4-D) degradation pathway.


The work can be divided into four steps. First, the promoter regions from the soil bacterium Ralstonia eutropha JMP134 will be cloned, and promoter lacZ fusions formed. Second, expression from both promoter regions in strain JMP134, the parent microorganism, will be tested under induced, uninduced, and stress conditions. Third, the promoter fusions will be transferred to a collection of 2,4-D degrading organisms and tested for levels of expression. Fourth, fusions will be compared and analyzed by qualitative and quantitative biochemical assays for differences in expression levels.

It is known that tfdR and tfdS both are able to regulate gene expression (Wright and Snyder, 1997); however, it may be that one is expressed to a greater level than the other or that one is expressed in a regulated fashion. This project should determine if one of the regulatory genes has a greater role in pathway regulation. The results also should provide clues as to the evolution of microbial regulatory systems of catabolic pathways, essential information for understanding the eventual fate of xenobiotic compounds in the environment. We expect expression from these promoters will not be highly regulated, though expression from the promoters of tfdR and tfdS may vary.

Supplemental Keywords:

fellowship, 2,4-dichlorophenoxyacetic acid, 2,4-D, promoter regions, tfdR, tfdS, Ralstonia eutropha JMP134, lacZ, gene regulation, xenobiotics, catabolic pathway,, RFA, Scientific Discipline, Ecosystem Protection/Environmental Exposure & Risk, POLLUTANTS/TOXICS, Ecosystem/Assessment/Indicators, exploratory research environmental biology, Genetics, Ecological Effects - Environmental Exposure & Risk, Environmental Microbiology, Biochemistry, Microorganisms, Ecological Indicators, degradation, genetically engineered microorganisms, bacteria, xenobiotics, microbial communities, genetic engineering, biochemical measurements, biochemical indicators, genetic differentiation, 2

Progress and Final Reports:

  • 2004
  • 2005
  • Final