Prediction of selenoprotein T structure and its response to selenium deficiency in chicken immune organs.

Selenoprotein T (SelT) is associated with the regulation of calcium homeostasis and neuroendocrine secretion. SelT can also change cell adhesion and is involved in redox regulation and cell fixation. However, the structure and function of chicken SelT and its response to selenium (Se) remains unclear. In the present study, 150 1-day-old chickens were randomly divided into a low Se group (L group, fed a Se-deficient diet containing 0.020 mg/kg Se) and a control group (C group, fed a diet containing sodium selenite at 0.2 mg/kg Se). The immune organs (spleen, thymus, and bursa of Fabricius) were collected at 15, 25, 35, 45, and 55 days of age. We performed a sequence analysis and predicted the structure and function of SelT. We also investigated the effects of Se deficiency on the expression of SelT, selenophosphate synthetase-1 (SPS1), and selenocysteine synthase (SecS) using RT-PCR and the oxidative stress in the chicken immune organs. The data showed that the coding sequence (CDS) and deduced amino acid sequence of SelT were highly similar to those of 17 other animals. Se deficiency induced lower (P < 0.05) levels of SelT, SPS1, and SecS, reduced the catalase (CAT) activity, and increased the levels of hydrogen peroxide (H2O2) and hydroxyl radical (-OH) in immune organs. In conclusion, the CDS and deduced amino acid sequence of chicken SelT are highly homologous to those of various mammals. The redox function and response to the Se deficiency of chicken SelT may be conserved. A Se-deficient diet led to a decrease in SelT, SecS, and SPS1 and induced oxidative stress in the chicken immune organs. To our knowledge, this is the first report of predictions of chicken SelT structure and function. The present study demonstrated the relationship between the selenoprotein synthases (SPS1, SecS) and SelT expression in the chicken immune organs and further confirmed oxidative stress caused by Se deficiency. Thus, the information presented in this study is helpful to understand chicken SelT structure and function. Meanwhile, the present research also confirmed the negative effects of Se deficiency on chicken immune organs.