Metallomics integrated with proteomics in deciphering metal-related environmental issues

The present work shows the possibilities of metallomics to characterize metal-linking proteins in Mus Musculus that could be used in environmental assessment. The laboratory mouse M. musculus is used as reference of gene/protein sequence databases to address methodological approaches based on changes in transcripts regulation, proteins expression and metalloproteins profiles in the environmental bio-indicator Mus spretus that has been demonstrated to be genetically homologous to M. Musculus. A metallomic approach using size exclusion chromatography with inductively coupled plasma-mass spectrometry detection (SEC-ICP-MS) was applied to cytosolic extracts from different M. musculus organs: lung, liver, spleen, kidney, brain, testicle, hearth and muscle. The resulting profiles of metallobiomolecules revealed the presence of a Cu-binding fraction in the 7-10 kDa range which was not present in the other tissues, can be associated to low molecular mass metallothionein-like proteins. The application of reverse phase chromatography with ICP-MS detection to this fraction gives two peaks that have been isolated for later identification by tandem mass spectrometry. The mass balance of copper evaluated by ICP-MS analysis of the digested brain fractions isolated by SEC and RP chromatography reveals good recoveries of the separations. The application of 2-DE to both crude brain extract and SEC fraction (7-10 kDa) reveals the considerably reduction of the number of proteins confirming that a good purification has been attained by SEC. This integration of metallomics with proteomics and transcriptomics can be useful in further studies involving the free-living mouse M. spretus for assessment of environmental issues. (C) 2009 Elsevier Masson SAS. All rights reserved.