Cloning and sequence analysis of the mercury resistance operon of Streptomyces sp. Strain CHR28 reveals a novel putative second regulatory gene.

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TitleCloning and sequence analysis of the mercury resistance operon of Streptomyces sp. Strain CHR28 reveals a novel putative second regulatory gene.
Publication TypeJournal Article
Year of Publication2000
AuthorsRavel, J, DiRuggiero, J, Robb, FT, Hill, RT
JournalJ Bacteriol
Volume182
Issue8
Pagination2345-9
Date Published2000 Apr
ISSN0021-9193
KeywordsAmino Acid Sequence, Base Sequence, Cloning, Molecular, Drug Resistance, Microbial, Genes, Bacterial, Genes, Regulator, Mercury, Molecular Sequence Data, Operon, Promoter Regions, Genetic, Sequence Analysis, DNA, Sequence Homology, Amino Acid, Streptomyces
Abstract

A DNA library of pRJ28, a large linear plasmid encoding mercury resistance, was constructed, and the mercury resistance genes were cloned. The 5,921-bp sequence was analyzed and showed a high degree of similarity to the Streptomyces lividans 1326 mercury resistance operon. Genes merR, merT, merP, and orfIV were found in a similar order and in a single transcription unit. merA and merB were found to be transcribed in the opposite direction to genes merR, merT, merP, and orfIV, as in S. lividans 1326. A novel putative regulatory gene, orfX, was found 22 bp downstream of merA. orfX encodes a 137-amino acid protein with a potential helix-turn-helix motif in the N-terminal domain, characteristic of the MerR family of transcriptional regulators. Transcriptional studies showed that orfX is cotranscribed with merA and merB. It is hypothesized that orfX plays a role in the regulation of the mercury resistance operon, probably by binding at the MerR operator site.

Alternate JournalJ. Bacteriol.
PubMed ID10735885
PubMed Central IDPMC111291