Reconstruction of the transcriptional regulatory networks in the kidney of desert-adapted species.

Desert animals have evolved systems that enable them to thrive under dry conditions. A plethora of adaptations are well studied and, more recently, the molecular underlying mechanisms have been investigated, but these are not fully understood. We recently characterised the kidney transcriptomic adaptations of camels and jerboas that enable these animals to withstand water deprivation, revealing a role for cholesterol in camels. Here, we aim to further mine these data and run reconstruction of transcriptional regulatory networks (TRN) analyses in camel, jerboa and olive mouse kidneys under different water regimes. We identify a total of 283 differentially expressed transcription factors (TFs) and 209 regulatory networks among all species. Among them, we find SREBF1 and SREBF2, which are key TFs involved in the cholesterol biosynthesis pathway. We further explore this pathway using immunofluorescence imaging. Localisation and/or signal of SREBP2 seems to change across conditions in camels and jerboas, perhaps indicative of protein retention in the Golgi during dehydration. Together, these data confirm a role for cholesterol during dehydration. Moreover, reconstruction of TRN analyses reveal a new set of potentially interesting genes and networks that would otherwise be ignored, these include but are not limited to other genes involved in cholesterol metabolism.