A citrate-inducible gene, encoding a putative tricarboxylate transporter, is downregulated by the organic solvent DMSO in Agrobacterium tumefaciens.
OBJECTIVE
To investigate the effects of the organic solvent dimethyl sulfoxide (DMSO) on the expression of a citrate-inducible gene, encoding a putative tricarboxylate transporter, in Agrobacterium tumefaciens.


RESULTS
By two-dimensional gel electrophoresis, we discovered a putative tricarboxylate transporter named ActC, whose expression was downregulated by DMSO. The expression of actC is also induced by tricarboxylates but not affected by other organic acids of the TCA cycle. Intriguingly, transcriptional activation of actC by citrate is compromised in the presence of DMSO. Furthermore, expression of actC is abolished by deletion of actDE, encoding a putative two-component regulatory system upstream of the actCBA gene cluster.


CONCLUSIONS
actC is a citrate-inducible gene that is repressed by DMSO and whose expression is likely regulated by a two-component system.


CONCLUSIONS
This study provides useful information as to a potential DMSO-regulatory system of A. tumefaciens or other soil bacteria when encountering DMSO in nature. In addition, DMSO-regulated genes should be taken into account for studies in which bacterial cultures were treated with compounds dissolved in DMSO.
Liu
A-C
AC
Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.
Shih
H-W
HW
Hsu
T
T
Lai
E-M
EM
D016960:Agrobacterium tumefaciens / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002951:Citrates; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics; D011401:Promoter Regions, Genetic
D002352:Carrier Proteins; D002951:Citrates; C020723:citrate-binding transport protein; D004121:Dimethyl Sulfoxide