A 5′ Promoter Region SNP in CTSC Leads to Increased Hypoxia Tolerance in Changfeng Silver Carp (Hypophthalmichthys molitrix)

作者：Nannan Feng, Xiaohui Li, Hang Sha, Xiangzhong Luo, Guiwei Zou, Jiquan Zhang, Hongwei Liang · 发表于：Animals · 年份：2025 · DOI：10.3390/ani15040532 · 被引用次数：3 · 研究领域：Physiological and biochemical adaptations、Aquaculture disease management and microbiota、Cancer, Hypoxia, and Metabolism

Silver carp is a critically significant species in freshwater aquaculture in China, characterized by its limited tolerance to hypoxia. In this study, a significant SNP locus at Chr8: 29647765 (T/C) associated with hypoxia tolerance traits was identified in Changfeng silver carp, and the homozygotic CC genotype exhibited higher hypoxic tolerance than the homozygotic TT and heterozygotic TC genotypes. Under hypoxic conditions, the hemoglobin concentration increased, with the CC genotype demonstrating a significantly higher level compared with the TT genotype; the activities of antioxidant enzymes including catalase and superoxide dismutase were significantly higher in the CC genotype than in the other genotypes; the area of the gill lamellae was significantly smaller in the CC genotype than in the TT and TC genotypes; and the number of apoptotic cells in the brain was significantly lower in the CC genotype than in the TT and TC genotypes. Sequence analysis showed that this SNP was located in the promoter region of the cathepsin C (CTSC) gene. The expression levels of the CTSC gene were analyzed across the three genotypes, revealing that the CC genotype exhibited significantly lower expression compared with the TT and TC genotypes under hypoxia. This finding suggests that the SNP associated with the CC genotype leads to reduced CTSC expression, which may facilitate better physiological adaptation to hypoxia. Analysis of the promoter region of CTSC found a unique predicted hypoxi...