title: Characterization and dietary regulation of oligopeptide transporter (PepT1) in different ploidy fishes.
abstract: The oligopeptide transporter (PepT1) is located on the brush-border membrane of the intestinal epithelium which has been regarded as a mediator of protein absorption. Here, we cloned and characterized PepT1 genes from diploid (red crucian carp), triploid and tetraploid fish. Then, the PepT1 expression pattern in different tissues and embryogenesis were assayed. Meanwhile, using real-time PCR and western blotting, we showed the expression profiles of diets with different protein levels, protein sources and additives (sodium butyrate) in triploids. The cDNAs of the three different ploidy fishes have a high sequence similarity of PepT1 among vertebrates. PepT1 mRNA expression was also developmentally regulated and showed the strongest expression around the 2-cell and 4-cell stage in all three kinds of fishes. The maternal transcripts were first detected in eggs and dropped from blastula stage to muscle contraction stage. Tissue expression studies showed higher expression of PepT1 genes in the intestines of fishes compared with other tissues. In adults, triploids showed significantly higher expression levels of PepT1 in the intestines of the three kinds of ploidy fishes during breeding season and non-breeding season. In addition, high or low protein level diets both promote PepT1 expression in the intestine. We also confirmed that fish meal showed a significant increase in PepT1 expression than soybean meal in triploid intestines. Furthermore, sodium butyrate additives induce PepT1 expression that may be mediated by CDX2 and CREB. This research provides a new insight into protein absorption and its regulation in triploid fish.
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410081, China; Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410081, China; Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410081, China. Electronic address: lsj@hunnu.edu.cn.
authors.forename: Shaojun
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Junchang
authors.initials: J
authors.lastname: Feng
authors.affiliation: Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Shuangqing
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Xiong
authors.affiliation: Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Dizhi
authors.initials: D
authors.lastname: Xie
authors.affiliation: Department of Biotechnology and Environmental Science, Changsha University, Changsha 410003, China.
authors.forename: Jianshe
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410081, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000818:Animals; D002347:Carps / Q000196:embryology* / Q000235:genetics; D029941:Fish Proteins / Q000096:biosynthesis* / Q000235:genetics; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D007413:Intestinal Mucosa / Q000166:cytology / Q000196:embryology*; D021381:Protein Transport / Q000502:physiology; D027981:Symporters / Q000096:biosynthesis* / Q000235:genetics; D057891:Tetraploidy; D057885:Triploidy
chemical_list: D029941:Fish Proteins; D027981:Symporters
keywords: Dietary protein level; Peptide transporter 1; Red crucian carp; Sodium butyrate; Tetraploid; Triploid