Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, Genetics & Heredity, catabolic transposons, biphenyl degradation, transcriptional regulation, Tn4371, Ralstonia eutropha, ALCALIGENES-EUTROPHUS CH34, RANGE CLONING VECTOR, MOLECULAR CHARACTERIZATION, NUCLEOTIDE-SEQUENCE, ESCHERICHIA-COLI, PLASMIDS, IDENTIFICATION, RESISTANCE, PROMOTER, PBBR1MCS, Amino Acid Sequence, Bacterial Proteins, Base Sequence, Biphenyl Compounds, Blotting, Northern, DNA Primers, DNA Transposable Elements, DNA, Bacterial, DNA-Binding Proteins, Escherichia coli Proteins, Gene Expression Regulation, Bacterial, Genes, Regulator, Molecular Sequence Data, Multigene Family, Operon, Promoter Regions, Genetic, Repressor Proteins, Sequence Homology, Amino Acid, Transcription Factors, 0604 Genetics, 0607 Plant Biology, Plant Biology & Botany, 3105 Genetics, 3108 Plant biology

Abstract:

Tn4371, a 55-kb catabolic transposon originally isolated from Ralstonia eutropha A5, carries genes for the degradation of biphenyl/4-chlorobiphenyl, which are clustered on a 13-kb DNA segment located in the middle of the element. DNA sequencing revealed that two potential regulatory genes, bphR and bphS, border this region. Transcriptional fusion experiments using bphC as a reporter gene, Northern hybridization and primer extension analysis led to the conclusion that the transposon-encoded genes bphEFGA1A2A3BCD form an operon transcribed from a sigma70 promoter, pE. Transcription from pE was not influenced by deletion of the bphR gene of Tn4371, which should encode a LysR-like regulator. The bphS gene product negatively regulated pE, and displayed significant similarity to GntR-like regulators. This is the first reported example of a GntR-like regulator involved in the control of an aromatic degradation pathway.