cbx2 is a functional target of the let-7 family in the gonad of Japanese flounder (Paralichthys olivaceus)

Yahui Wu; Yangyang Wang; Yidong Xue; Ningning Wu; Jikui Wu; Junling Zhang

doi:10.1016/j.cbpb.2022.110799

cbx2 is a functional target of the let-7 family in the gonad of Japanese flounder (Paralichthys olivaceus)

Comp Biochem Physiol B Biochem Mol Biol. 2023 Jan:263:110799. doi: 10.1016/j.cbpb.2022.110799. Epub 2022 Sep 22.

Authors

Yahui Wu¹, Yangyang Wang¹, Yidong Xue¹, Ningning Wu¹, Jikui Wu², Junling Zhang³

Affiliations

¹ Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China.
² Laboratory of Quality and Safety Risk Assessment for Aquatic Product on Storage and Preservation, Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China. Electronic address: jkwu@shou.edu.cn.
³ Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Ocean University, Shanghai 201306, China. Electronic address: jlzhang@shou.edu.cn.

PMID: 36155820
DOI: 10.1016/j.cbpb.2022.110799

Abstract

As a key member of the miRNA family, the role and target gene of the let-7 family in the gonad of Japanese flounder (Paralichthys olivaceus) is unclear. Chromobox homolog 2 (CBX2) is one of the core components of the polycomb group complex (PcG) and significantly influences gonadal development. The deletion of CBX2 can lead to sex reversal in mammals. Therefore, exploring the relationship between the let-7 family and cbx2 is crucial to clarify the role played by the let-7 family in the gonad of Japanese flounder. We predicted and verified the target interaction between the let-7 family and cbx2. The results showed that cbx2 was a direct target of let-7d, let-7e, let-7g, let-7j, and let-7b. Among them, let-7d, let-7e, let-7g, and let-7j exhibited an extremely significant targeting relationship with cbx2 (p < 0.001). Taking let-7g as an example, we further investigated the regulatory role between let-7g and cbx2 in the gonad by miRNA overexpression and inhibition experiments in primary testis cells. The results revealed that let-7g could negatively regulate cbx2 at the level of primary testis cells. And the expression of sf1 (steroidogenic factor 1) was also significantly decreased after the interference of cbx2 siRNA. This suggests that the let-7 family may be involved in the Japanese flounder gonadal development via targeting cbx2.

Keywords: Gonadal development; Let-7 family; Paralichthys olivaceus; cbx2.