Involvement of several transcriptional regulators in the differential expression of tfd genes in Cupriavidus necator JMP134

Authors

  • Nicole Trefault Pontifical Catholic University of Chile, Santiago, Chile
  • Leda Guzmán Pontifical Catholic University of Chile, Santiago, Chile
  • Heidi Pérez Pontifical Catholic University of Chile, Santiago, Chile
  • Margarita Godoy Pontifical Catholic University of Chile, Santiago, Chile
  • Bernardo González Faculty of Engineering and Science, Adolfo Ibáñez University, Santiago, Chile

Keywords:

Cupriavidus necator, LysR transcriptional regulators, pJP4 catabolic plasmid, tfd catabolic genes

Abstract

Cupriavidus necator JMP134 has been extensively studied because of its ability to degrade chloroaromatic compounds, including the herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) and 3-chlorobenzoic acid (3-CB), which is achieved through the pJP4-encoded chlorocatechol degradation gene clusters: tfdCIDIEIFI and tfdDIICIIEIIFII. The present work describes a different tfd-genes expression profile depending on whether C. necator cells were induced with 2,4-D or 3-CB. By contrast, in vitro binding assays of the purified transcriptional activator TfdR showed similar binding to both tfd intergenic regions; these results were confirmed by in vivo studies of the expression of transcriptional lacZ fusions for these intergenic regions. Experiments aimed at investigating whether other pJP4 plasmid or chromosomal regulatory proteins could contribute to the differences in the response of both tfd promoters to induction by 2,4-D and 3-CB showed that the transcriptional regulators from the benzoate degradation pathway, CatR1 and CatR2, affected 3-CB- and 2,4-D-related growth capabilities. It was also determined that the ISJP4-interrupted protein TfdT decreased growth on 3-CB. In addition, an ORF with 34% amino acid identity to IclR-type transcriptional regulator members and located near the tfdII gene cluster module was shown to modulate the 2,4-D growth capability. Taken together, these results suggest that tfd transcriptional regulation in C. necator JMP134 is far more complex than previously thought and that it involves proteins from different transcriptional regulator families. [Int Microbiol 2009; 12(2):97-106]

Author Biographies

Nicole Trefault, Pontifical Catholic University of Chile, Santiago, Chile

Pontifical Catholic University of Chile, Santiago, Chile

Leda Guzmán, Pontifical Catholic University of Chile, Santiago, Chile

Pontifical Catholic University of Chile, Santiago, Chile

Heidi Pérez, Pontifical Catholic University of Chile, Santiago, Chile

Pontifical Catholic University of Chile, Santiago, Chile

Margarita Godoy, Pontifical Catholic University of Chile, Santiago, Chile

Pontifical Catholic University of Chile, Santiago, Chile

Bernardo González, Faculty of Engineering and Science, Adolfo Ibáñez University, Santiago, Chile

Faculty of Engineering and Science, Adolfo Ibáñez University, Santiago, Chile

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Published

2010-01-13

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Section

Research Articles