Identification of an archaeal mercury regulon by chromatin immunoprecipitation

Deepak Rudrappa, Andrew I. Yao, Derrick White, Benjamin J. Pavlik, Raghuveer Singh, Marc T. Facciotti, Paul Blum

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Mercury is a heavy metal and toxic to all forms of life. Metal exposure can invoke a response to improve survival. In archaea, several components of a mercury response system have been identified, but it is not known whether metal transport is a member of this system. To identify such missing components, a peptide-tagged MerR transcription factor was used to localize enriched chromosome regions by chromosome immunoprecipitation combined with DNA sequence analysis. Such regions could serve as secondary regulatory binding sites to control the expression of additional genes associated with mercury detoxification. Among the 31 highly enriched loci, a subset of five was pursued as potential candidates based on their current annotations. Quantitative reverse transcription-PCR analysis of these regions with and without mercury treatment in WT and mutant strains lacking merR indicated significant regulatory responses under these conditions. Of these, a Family 5 extracellular solute-binding protein and the MarR transcription factor shown previously to control responses to oxidation were most strongly affected. Inactivation of the solute-binding protein by gene disruption increased the resistance of mutant cells to mercury challenge. Inductively coupled plasma-MS analysis of the mutant cell line following metal challenge indicated there was less intracellular mercury compared with the isogenic WT strain. Together, these regulated genes comprise new members of the archaeal MerR regulon and reveal a cascade of transcriptional control not previously demonstrated in this model organism.

Original languageEnglish (US)
Pages (from-to)2423-2433
Number of pages11
JournalMicrobiology (United Kingdom)
Issue number12
StatePublished - Dec 2015

ASJC Scopus subject areas

  • Microbiology

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