Abstract
Epidermal growth factor receptor (EGFR) is one of the most important tyrosine kinase receptor families, which plays a pivotal role in cell signaling transduction and physiological processes. Studies on the EGFR gene in humans and other species have demonstrated its pivotal role in regulating the sodium ion balance and mediating sodium and water reabsorption in the kidney's proximal tubules. However, the impact of EGFR gene in how the Yarkand hare (Lepus yarkandensis) adapts to extreme environmental habitat remains unclear. The Yarkand hare is a desert-dwelling animal with multiple adaptations to cope with drought. Given the important physiological function of EGFR gene, we strived to understand its role in arid environment and explore the molecular mechanism of drought tolerance in the Yarkand hare. We first performed segmental cloning of the CDS of the Yarkand hare EGFR gene. Then, we constructed the phylogenetic tree of the Yarkand hare's EGFR gene and compared it with that of other species. The results showed that the Yarkand hare was most closely related to the Tolai hare (Lepus tolai). Through quantitative reverse transcription polymerase chain reaction (RT-qPCR), we discovered that EGFR expression in the kidneys of the Yarkand hare was higher than in the allopatric Tolai hare from non-arid areas. Therefore, we hypothesized that EGFR gene overexpression in the kidney of the Yarkand hare may play a crucial role in drought adaptability. Subsequently, we inserted CDS of EGFR gene into a pcDNA3.1-EGFP expression vector to construct recombinant plasmid, which was transfected into HeLa cells and overexpressed. RT-qPCR demonstrated a notable and statistically significant increase in EGFR mRNA expression and western blot proved stable expression of this protein in HeLa cells. Through cell experiments, EGFR gene overexpression markedly enhanced the survival of Hela cells subjected to NaCl, H(2)O(2), and heat stresses, increased superoxide dismutase activity, and decreased malondialdehyde content. In conclusion, these findings preliminarily suggest that EGFR might help the Yarkand hare adapt to extreme environmental conditions. EGFR manipulation in vivo could be a promising strategy to enhance the resilience of animals to extreme conditions.