Temperature-mediated changes in hepatic gene expression of a mammalian herbivore (Neotoma lepida)

The effects of ambient temperature and dietary plant toxins on differential gene expression in the liver were compared in herbivorous rodents (woodrats, genus Neotoma) using microarrays custom-designed for woodrats. Expression profiles revealed a greater number of up-egulated genes at 22C comapred to a thermoneutral temperature (27C). Genes and pathways up-regulated at 22C were related to growth and biosynthesis, suggesting the liver could be in a building state at this temperature. Conversely, genes associated with gluconeogenesis, apoptosis and protein misfolding, which likely reflected a more stressed state for the liver. Taken together, these results highlighted the important role of temperature on gene expression profiles in the desert woodrat. As crucial players in many ecosystems, understanding how herbivorous mammals will respond to climate change is imperative to accurately predict repercussions and aid in conservation efforts. Gene expression in woodrats was compared across 4 treatment groups (N= individuals 4 per group) based upon temperature (22C or 27C) and dietary plant toxins (control or creosote diets). Animals were temperature acclimated for at least 14 days, and then fed experimental diets for 8 days. RNA was extracted from liver tissue and one-color arrays were performed at the University of Utah Microarray Core facility.