Differential gene expression in ahr-1 mutants compared to wild-type C. elegans

The aryl hydrocarbon receptor (AHR) functions in higher organisims in development, metabolism and toxic responses. Its Caenorhabditis elegans (C. elegans) ortholog, AHR-1, facilitates neuronal development, growth and movement. We investigated the effect of AHR mutation on the transcriptional profile of L4 stage C. elegans using RNA-seq and quantitative real-time PCR in order to understand better AHR-1 function at the genomic level. Illumina HiSeq 2000 sequencing yielded 51.1, 61.2 and 54.0 million reads from wild-type controls, ahr-1(ia03) and ahr-1(ju145) mutants, respectively, providing detection of over 18,000 transcripts in each sample. Fourteen transcripts were over-expressed and 125 under-expressed in both ahr-1 mutants when compared to wild-type. Under-expressed genes included soluble guanylate cyclase (gcy) family genes, some of which were previously demonstrated to be regulated by AHR-1. A neuropeptide-like protein gene, nlp-20, and an F-box domain protein gene fbxa-192 and its pseudogenes fbxa-191 and fbxa-193 were also under-expressed. Conserved xenobiotic response elements were identified in the 5'' flanking regions of some but not all of the gcy, nlp-20 and fbxa genes. These results extend previous studies demonstrating control of gcy family gene expression by AHR-1, and furthermore suggest a role of AHR-1 in regulation of a neuropeptide gene as well as pseudogenes. Overall design: One sample was created from each of the following strains: wild-type N2, ahr-1(ia03) mutant and ahr-1(ju145) mutant. In data analysis, each mutant sample was individually compared to the wild-type sample to find differentially expressed genes.

3

Aarnio V, Heikkinen L, Peltonen J, Goldsteins G, Lakso M, Wong G