Microarray analysis of global gene expression in Caenorhabditis elegans exposed to potassium dichromate

Hexavalent chromium [Cr (VI)] can be considered as carcinogen heavy metal to human population. Especially, potassium dichromate [K₂Cr₂O₇; Cr (VI)] induces DNA damage response and oxidative stress. It also causes inhibition of protective process including DNA repair as well as apoptosis. However, genomic responses to Cr (VI) exposure in Caenorhabditis elegans (C. elegans) have not been performed yet. As an alternative animal model, C. elegans is well known model for genetical studies including mRNA expression (etc.) and also serves as a living biomonitor in ecotoxicological field. Moreover, recognition of chromium biomarkers for the toxicity assessment is of prime importance. In present study, we have investigated the changes of gene expression in C. elegans in response to potassium dichromate exposure using microarray consisting of 22K nematode-specific oligonucleotide probes. We have found 28 genes as a Cr (VI) responsive genes that were differentially expressed (>2 fold) following 24 hours exposure to potassium dichromate. In addition, using the comparative toxicogenomics database, we have deduced molecular targets including cyclin B, alpha-B crystalline, G-protein coupled receptor kinase, nucleobindin, U2AF splicing factor, and SR protein (splicing factor) in response to potassium dichromate toxicity in C. elegans. In consistency with previous studies in human, it has also found that alteration in expression level of these genes contributes to particular syndromes including cataract, prostatic neoplasms, liver disease and neurotoxicity syndromes. In conclusion, our investigation would be able to present precise route to figure out important biomarkers in response to potassium dichromate in the field of ecotoxicology.