Page 42 - 《水产学报》2025年第12期

何宏阳，等 水产学报, 2025, 49(12): 129103

Effect of setd7 on hypoxia tolerance in Nile tilapia (Oreochromis niloticus)

1,2
1,2
1,2
1,2
HE Hongyang , WANG Yifan , JIA Haiwang , ZHOU Yan ,
1,2
CHEN Liangbiao , ZU Yao 1,2*
1. International Research Center for Marine Biosciences, Ministry of Science and Technology,
Shanghai Ocean University, Shanghai 201306, China;
2. Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education,
Shanghai Ocean University, Shanghai 201306, China

Abstract: This study aims to explore the function of the methyltransferase gene setd7 in hypoxia tolerance in fish, using Nile
tilapia (Oreochromis niloticus) as the experimental model. By employing gene editing technology, we constructed setd7 gene
mutation lines to assess their physiological responses and tolerance capabilities in low oxygen environments, providing theoret-
ical basis and experimental materials for molecular breeding of hypoxia tolerant fish and research on the functional mechan-
isms of methyltransferases. Using CRISPR/Cas9 gene editing technology, specific knockout targets were designed for the con-
served amino acid region of the second exon of the setd7 gene in O. niloticus, and microinjection was performed on one cell
fertilized eggs. The gene editing efficiency was verified through T7E1 enzyme digestion experiments and sequencing analysis,
+/−
successfully obtaining the setd7 mutation line with a -23 bp base deletion. Further, one month old F 1 generation tilapia were
subjected to hypoxic stress treatment to observe their hypoxia characteristics and survival time, assessing their hypoxia toler-
+/−
ance. The experimental results showed that the setd7 mutation line exhibited a loss of function of the SETD7 protein due to a
frameshift mutation, with a significantly reduced expression level of the setd7 gene compared to the wild type. In the hypoxic
+/−
stress experiment, the setd7 mutant tilapia demonstrated stronger hypoxia tolerance, with the onset of surface swimming
occurring significantly later than in the wild type, and a markedly extended survival time in low oxygen environments. This
indicates that the mutation of the setd7 gene significantly enhances the hypoxia adaptation ability of tilapia. This study found
that mutations in the methyltransferase gene setd7 can significantly improve the hypoxia tolerance of Nile tilapia, providing
important experimental materials and theoretical foundations for molecular breeding of hypoxia tolerant tilapia. Additionally,
this research lays a scientific foundation for further exploration of the molecular mechanisms and functional studies of methyl-
transferases in hypoxia adaptation.

Key words: Oreochromis niloticus; methyltransferase; setd7 gene; gene editing; hypoxia tolerance
First author: HE Hongyang. E-mail: 572192582@qq.com
Corresponding author: ZU Yao. E-mail: yzu@shou.edu.cn
Funding projects: National Key Research and Development Program of China (2024YFD2402400, 2022YFD2400801);
National Natural Science Foundation of China (32170423, 31501166)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
9