Transcriptional changes in the absence of nth-1, xpa-1 and nth-1;xpa-1

Background: The ability of an organism to repair damages to DNA is inextricably linked to aging and cancer. We have characterized and compared the transcriptome of C. elegans mutants deficient in DNA base excision repair, nucleotide excision repair or both to elucidate the transcriptional changes incurred by the reduction of these repair pathways. Results: The gene expression signatures from nth-1, xpa-1 and nth-1;xpa-1 are deciphered. We find that the single mutants are more similar in overall transcriptomic activity compared to the double mutant and their corresponding wild-type (N2). Interestingly, of the enriched Gene Ontology terms for respective mutants are aging and proteolysis for nth-1, aging, energy production and unfolded protein response for xpa-1, and DNA repair and regulation of M-phase for nth-1;xpa-1. We also find striking similarities between the biological processes found to be enriched in the single mutants, which show a shared response in genes associated with aging and insulin signaling. Loss of either BER or NER induces an oxidative stress response, but does not confer resistance to heat shock. Conclusion: Taken together, our study provides a general overview about the global transcriptional changes in the absence of nth-1, xpa-1 and nth-1;xpa-1. Our results also point to a two-tiered global response to combat the effects of decreased DNA repair capacity. C. elegans RNAi mutants deficient in DNA excision repair, nth-1, xpa-1, nth-1;xpa-1 and the corresponding wild-type N2, were subjected to Affymetrix C. elegans microarrays. For nth-1, triplicates were run, whereas for xpa-1, nth-1;xpa-1 and N2, duplicates were run.