Rengaraj Deivendran, Truong Anh Duc, Hong Yeojin, Pitargue Franco Martinez, Kim Jong Hyuk, Hong Yeong Ho, Han Jae Yong, Kil Dong Yong
Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea; Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea.
Department of Animal Science and Technology, Chung-Ang University, Anseong-si, Gyeonggi-do 17546, Republic of Korea; Department of Biochemistry and Immunology, National Institute of Veterinary Research, 86 Truong Chinh, Dong Da, Hanoi 100000, Viet Nam.
Res Vet Sci. 2019 Apr;123:99-110. doi: 10.1016/j.rvsc.2018.12.018. Epub 2018 Dec 23.
Among the eight forms of vitamin E, the liver preferentially releases α-tocopherol into the circulation and it is distributed to the non-liver tissues. In the hepatocytes, alpha tocopherol transfer protein (TTPA) specifically recognizes α-tocopherol with 2R-configuration and facilitates its intracellular transfer. The identification and characterization of TTPA expression have not been demonstrated in avian species. Therefore, the objectives of this study were to identify avian TTPAs, to compare the sequence conservation, phylogenetic relationship, protein interactions, and disease associations of chicken TTPA with those of human and vertebrate TTPA, and to characterize the tissue expression of the TTPA gene in chickens fed diets supplemented with different amounts of α-tocopherol. Our results suggest that the chicken TTPA was highly conserved with the human and vertebrate TTPA, and consisted of a cellular retinaldehyde binding protein and TRIO guanine exchange factor (CRAL_TRIO) domain. Feeding diets supplemented with increasing amounts of α-tocopherol (25 IU/Kg, 50 IU/Kg, or 100 IU/Kg) to broiler chickens had no effects on growth performance compared with feeding basal diets containing no supplemental α-tocopherol. The expression of TTPA gene was detected high in the liver of chickens in response to dietary α-tocopherol concentrations, whereas its expression was very low or undetectable in the non-liver tissues. In conclusion, the chicken TTPA protein sequence is highly conserved with other avian and vertebrate TTPA protein sequences. The higher expression of TTPA gene in the chicken liver in response to dietary α-tocopherol concentrations may suggest its crucial role in transporting α-tocopherol in the chicken liver.
在维生素E的八种形式中，肝脏优先将α-生育酚释放到循环系统中，并将其分布到非肝脏组织。在肝细胞中，α-生育酚转运蛋白（TTPA）特异性识别具有2R构型的α-生育酚，并促进其在细胞内的转运。尚未在禽类中证实TTPA表达的鉴定和特征。因此，本研究的目的是鉴定禽类TTPA，比较鸡TTPA与人及脊椎动物TTPA的序列保守性、系统发育关系、蛋白质相互作用和疾病关联，并表征在饲喂不同量α-生育酚日粮的鸡中TTPA基因的组织表达。我们的结果表明，鸡TTPA与人及脊椎动物TTPA高度保守，由细胞视黄醛结合蛋白和TRIO鸟嘌呤交换因子（CRAL_TRIO）结构域组成。与饲喂不含补充α-生育酚的基础日粮相比，给肉鸡饲喂补充量不断增加的α-生育酚（25 IU/Kg、50 IU/Kg或100 IU/Kg）日粮对生长性能没有影响。响应日粮α-生育酚浓度，在鸡的肝脏中检测到TTPA基因的高表达，而在非肝脏组织中其表达非常低或无法检测到。总之，鸡TTPA蛋白序列与其他禽类和脊椎动物TTPA蛋白序列高度保守。响应日粮α-生育酚浓度，鸡肝脏中TTPA基因的较高表达可能表明其在鸡肝脏中转运α-生育酚方面的关键作用。
