The Functional Identification of the CYP2E1 Gene in the Kidney of Lepus yarkandensis

This study aims to identify the function of the cytochrome P450 2E1 (CYP2E1) gene in the kidneys of Lepus yarkandensis. CYP2E1 is a significant metabolic enzyme involved in the metabolism of various endogenous and exogenous compounds and is associated with the occurrence and progression of multiple diseases. Given L. yarkandensis's ability to survive in the extremely arid L. yarkandensis, we hypothesize that CYP2E1 in its kidneys plays a crucial role in adaptability. Through molecular cloning and sequence analysis, we discovered that the CYP2E1 gene of Lepus yarkandensis encodes a protein of 493 amino acids. The 493-amino acid protein encoded by the Lepus yarkandensis CYP2E1 gene shows 13 amino acid variation sites compared to the homologous protein in Oryctolagus cuniculus. The protein is primarily localized to the endoplasmic reticulum membrane and lacks transmembrane structures. In the yeast expression system, the heterologous expression of the CYP2E1 gene enhanced the yeast's tolerance to drought, salinity, and high temperatures, achieved by increasing antioxidant enzyme activity and reducing levels of oxidative stress markers. Additionally, this study identified a "Yeast Oxidative Stress Lethal Threshold (Yeast OSLT)" under specific stress conditions. Once this threshold is exceeded, the cell's antioxidant defense system can no longer maintain cellular homeostasis, leading to massive cell death. Although CYP2E1 did not change this threshold, it contributed to cell survival to some extent. These findings not only reveal the function of L. yarkandensis CYP2E1 in stress adaptation but also provide valuable molecular insights into its survival strategy in extreme environments.