Functional characterization of Bcl-2-related ovarian killer (Bok) in apoptosis and antibacterial immunity in Trachinotus ovatus.

Authors

Zhenjie Cao, Zhiru Liu, Jing Zhang, Ying Chen, Yaqi Huo, Longxiang You, Lintao Meng, Ying Wu, Chen Zhang, Yongcan Zhou, Yun Sun

Published in

Fish & shellfish immunology. Pages 111678. Aug 24, 2026. Epub Aug 24, 2026.

Abstract

Bok (Bcl-2-related ovarian killer) is a pro-apoptotic member of the Bcl-2 family that plays a critical role in the intrinsic apoptotic pathway in mammals. However, its functional characterization in teleost fish remains largely unexplored. In this study, we identified and characterized TroBok, a Bok ortholog from golden pompano (Trachinotus ovatus), and investigated its role in apoptosis and antibacterial immunity. The full-length coding sequence of TroBok is 642 bp, encoding a protein of 213 amino acids containing four conserved BH domains (BH1-BH4). TroBok was ubiquitously expressed in all tissues examined, with the highest abundance in the head kidney, and was significantly upregulated upon Vibrio harveyi challenge. Subcellular localization revealed that TroBok is predominantly distributed in the cytoplasm. Functional analysis in golden pompano snout (GPS) cells stimulated with rFla B, the flagellin protein of V. harveyi, demonstrated that TroBok overexpression significantly increased apoptosis, promoted mitochondrial membrane potential (MMP) loss, induced DNA fragmentation, and enhanced Caspase-9 and Caspase-3 activities, whereas TroBok knockdown produced opposite effects. Furthermore, TroBok overexpression upregulated pro-apoptotic genes (p53, cytochrome c, Caspase-3, Caspase-7, and Caspase-9) and downregulated the anti-apoptotic Bcl-2, indicating that TroBok activates the intrinsic mitochondrial apoptotic pathway. In vivo, TroBok overexpression significantly reduced V. harveyi burdens in the liver, spleen, and head kidney, whereas TroBok silencing markedly increased bacterial loads. Mechanistically, TroBok promoted apoptosis of head kidney macrophages and elevated Caspase-9 and Caspase-3 activities in head kidney tissues, indicating that the antibacterial effect of TroBok may be associated with its pro-apoptotic function. Our results indicate that TroBok exerts a conserved pro-apoptotic function via the mitochondrial pathway and contributes to antibacterial immunity in golden pompano, providing new insights into the role of BOK family proteins in teleost host defense.

PMID:
42637163
Bibliographic data and abstract were imported from PubMed on 25 Aug 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.