Characterization of heat shock protein expression and its application to temporal gene expression in the nematode Pristionchus pacificus

Temporal gene expression systems are widely used to examine gene functions at specific developmental stages. One method applied in temporal gene expression systems in many organisms is the heat-inducible gene expression system, which utilizes a heat shock promoter with evolutionarily conserved heat shock elements. The nematode Pristionchus pacificus is a satellite model system comparable to Caenorhabditis elegans, with unique developmental traits but lacking genetic tools for temporal gene expression. To establish a temporal gene expression system in P. pacificus , we investigated genes that were highly induced by heat shock. RNA-seq analysis revealed thousands of differentially expressed genes after a 2-hour heat shock event. One of the highly induced genes, PPA12242 , is an ortholog of C. elegans hsp-16.41 , and reporter transgenic animals have indicated that the genomic fragment upstream of this gene can induce gene expression in response to heat shock. PPA12242 can be highly induced in specific larval stages, which seem to be vulnerable to heat stress in some phenotypes. Taken together, we identified a potential heat shock promoter in P. pacificus that is applicable to the temporal gene expression system in this species.