Transcriptomic changes in the jerboa supraoptic nucleus during osmotic stress: <scp>PCSK1</scp> and <scp>PTPRN</scp> changes are conserved across desert and mesic species

The supraoptic nucleus (SON) is a hypothalamic region essential for the orchestration of osmoregulation in mammals. We sought to understand how gene expression in the SON is orchestrated in a rodent species adapted for survival in arid desert conditions. After an acclimatisation period, we compared the male and female trancriptomes of the Lesser Egyptian jerboa (Jaculus jaculus) SON under euhydrated, dehydrated, and rehydrated conditions. Gene expression in the jerboa SON was remarkably stable across the conditions with only 46 differentially expressed genes (DEGs) after dehydration and 4 DEGs after rehydration compared to controls; far fewer than previously shown to respond in the jerboa kidney and in the SON of mesic species. When comparing across species (jerboa, camel, and rat), the genes PCSK1 and PTPRN were consistently regulated under conditions of osmotic stress suggesting they have important conserved functions. The dehydration response in jerboa SON is tightly regulated. PCSK1 and PTPRN are identified as conserved components of the response, indicating their importance.