C. elegans metallothioneins: response to and defence against ROS toxicity

Mol Biosyst. 2011 Aug;7(8):2397-406. doi: 10.1039/c1mb05114h. Epub 2011 Jun 7.

Abstract

The genome of the nematode Caenorhabditis elegans encodes for two multifunctional metal binding metallothioneins (MTs), CeMT-1 and CeMT-2. Here we applied qPCR to identify a transcriptional up-regulation following the exposure to free radical generators (ROS) paraquat or hydrogen peroxide, a trend that was confirmed with Pmtl::GFP expressing alleles. The deletion of the MT loci resulted in an elevation of in vivo levels of hydrogen peroxide and exposure to ROS caused a reduction in total egg production, growth and life span in wild type nematodes, effects that were particularly pronounced in the CeMT-2 and double knockout. Moreover, in vitro incubation of recombinant MTs with hydrogen peroxide demonstrated the presence of direct oxidation of the CeMTs, with zinc released from both isoforms and concomitant formation of intra-molecular disulfides. Finally, metabolic profiling (metabolomic) analysis of wild type and MT knockouts in the presence/absence of oxidative stressors, confirmed the overall trend described by the other experiments, and identified 2-aminoadipate as a potential novel small-molecule marker of oxidative stress. In summary, this study highlights that C. elegans metallothioneins scavenge and protect against reactive oxygen species and potentially against oxidative stress, with CeMT-2 being more effective than CeMT-1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Analysis of Variance
  • Animals
  • Caenorhabditis elegans / drug effects
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / growth & development
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / biosynthesis
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cluster Analysis
  • Eggs
  • Gene Deletion
  • Gene Knockout Techniques
  • Hydrogen Peroxide / metabolism
  • Hydrogen Peroxide / toxicity
  • Metabolomics
  • Metallothionein / biosynthesis
  • Metallothionein / genetics
  • Metallothionein / metabolism*
  • Molecular Sequence Data
  • Oxidative Stress / physiology*
  • Paraquat / toxicity
  • Polymerase Chain Reaction
  • Reactive Oxygen Species / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Reactive Oxygen Species
  • Metallothionein
  • Hydrogen Peroxide
  • Paraquat