Molecular Identification of Anion Exchange Protein 3 in Pacific White Shrimp (Litopenaeus vannamei): mRNA Profiles for Tissues, Ontogeny, Molting, and Ovarian Development and Its Potential Role in Stress-Induced Gill Damage

Xin Zhang; Hao Yang; Hongmei Li; Ting Chen; Yao Ruan; Chunhua Ren; Peng Luo; Yanhong Wang; Bing Liu; Huo Li; Ping Zhong; Jiquan Zhang; Xiao Jiang; Chaoqun Hu

doi:10.3389/fphys.2021.726600

Molecular Identification of Anion Exchange Protein 3 in Pacific White Shrimp (Litopenaeus vannamei): mRNA Profiles for Tissues, Ontogeny, Molting, and Ovarian Development and Its Potential Role in Stress-Induced Gill Damage

Front Physiol. 2021 Sep 30:12:726600. doi: 10.3389/fphys.2021.726600. eCollection 2021.

Authors

Xin Zhang^{1

2}, Hao Yang³, Hongmei Li⁴, Ting Chen¹, Yao Ruan¹, Chunhua Ren¹, Peng Luo¹, Yanhong Wang¹, Bing Liu^{1

2}, Huo Li⁵, Ping Zhong⁶, Jiquan Zhang³, Xiao Jiang¹, Chaoqun Hu¹

Affiliations

¹ CAS Key Laboratory of Tropical Marine Bio-resources and Ecology (LMB), Guangdong Provincial Key Laboratory of Applied Marine Biology (LAMB), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
² College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China.
³ College of Life Sciences, Hebei University, Baoding, China.
⁴ Guangdong Laboratory Animals Monitoring Institute, Guangzhou, China.
⁵ Jinyang Biotechnology Co. Ltd., Maoming, China.
⁶ Institute of Hydrobiology, College of Life Science and Technology, Jinan University, Guangzhou, China.

Abstract

Bicarbonate (HCO₃ ^-) transport mechanisms play an essential role in the acid-base homeostasis of aquatic animals, and anion exchange protein 3 (AE3) is a membrane transport protein that exchanges Cl^-/HCO₃ ^- across the cell membrane to regulate the intracellular pH. In this study, the full-length cDNA of AE3 (Lv-AE3) was obtained from the Pacific white shrimp (Litopenaeus vannamei). The Lv-AE3 cDNA is 4,943 bp in length, contains an open reading frame of 2,850 bp, coding for a protein of 949 amino acids with 12 transmembrane domains. Lv-AE3 shows high sequence homology with other AE3 at the protein level. Lv-AE3 mRNA was ubiquitously detected in all tissues selected, with the highest expression level in the gill, followed by the ovary, eyestalk and brain. By in situ hybridization, Lv-AE3-positive cells were shown predominant localization in the secondary gill filaments. The expression levels of Lv-AE3 were further investigated during the essential life processes of shrimp, including ontogeny, molting, and ovarian development. In this case, the spatiotemporal expression profiles of Lv-AE3 in L. vannamei were highly correlated with the activities of water and ion absorption; for example, increased mRNA levels were present after hatching, during embryonic development, after ecdysis during the molt cycle, and in the stage IV ovary during gonadal development. After low/high pH and low/high salinity challenges, the transcript levels of Lv-AE3 were reduced in the gill, while the cell apoptosis rate increased. In addition, knockdown of Lv-AE3 mRNA expression induced cell apoptosis in the gill, indicating a potential link between Lv-AE3 and gill damage. Altogether, this study thoroughly investigated the relationship between the mRNA expression profiles of Lv-AE3 and multiple developmental and physiological processes in L. vannamei, and it may benefit the protection of crustaceans from fluctuated aquatic environments.

Keywords: Litopenaeus vannamei; anion exchange protein 3; apoptosis; development; environmental stresses.