Characterization and expression analysis of seven selenoprotein genes in yellow catfish Pelteobagrus fulvidraco to dietary selenium levels

BackgroundSelenium (Se) appears in the selenoproteins in the form of selenocysteine (Sec) and is important for the growth and development of vertebrates. The present study characterized seven selenoproteins, consisting of the GPX1, GPX3, GPX4, SELENOW, SELENOP, TXNRD2 and TXNRD3 cDNAs in various tissues of yellow catfish, explored their regulation to dietary Se addition.Methods3′ and 5′ RACE PCR were used to clone full-length cDNA sequences of seven selenoprotein genes (GPX1, GPX3, GPX4, SELENOW, SELENOP, TXNRD2 and TXNRD3). Their molecular characterizations were analyzed, including conservative motifs and the SECIS elements. The phylogenetic trees were generated through neighbor-joining (NJ) method with MEGA 6.0 with 1000 bootstrap replications. Quantitative real-time PCR was used to explore their mRNA tissue distribution in the heart, anterior intestine, dorsal muscle, head kidney, gill, liver, brain, spleen and mesenteric fat. Yellow catfish (mixed sex) were fed diets with dietary Se contents at 0.03 (low Se), 0.25 (adequate Se) and 6.39 (high Se) mg Se/kg, respectively, for 12 weeks, and their spleen, kidney, testis and brain were used for the determination of the mRNA levels of the seven selenoproteins.ResultsThe seven selenoproteins had similar domains to their corresponding members of other vertebrates. They were widely expressed in nine tissues, including heart, liver, brain, spleen, head kidney, dorsal muscle, mesenteric fat, anterior intestine and gill, but showed tissue-dependent expression patterns. Dietary Se addition affected the expression of the seven genes in spleen, kidney, testis and brain tissues of yellow catfish.ConclusionTaken together, our study demonstrated the characterization, expression and regulation of seven selenoproteins, which increased our understanding of the biological functions of Se and selenoproteins in fish.     

Effects of selenium supplementation on diet-induced obesity in mice with a disruption of the selenocysteine lyase gene

BACKGROUNDThe amino acid selenocysteine (Sec) is an integral part of selenoproteins, a class of proteins mostly involved in strong redox reactions. The enzyme Sec lyase (SCLY) decomposes Sec into selenide allowing for the recycling of the selenium (Se) atom via the selenoprotein synthesis machinery. We previously demonstrated that disruption of the Scly gene (Scly KO) in mice leads to the development of obesity and metabolic syndrome, with effects on glucose homeostasis, worsened by Se deficiency or a high-fat diet, and exacerbated in male mice. Our objective was to determine whether Se supplementation could ameliorate obesity and restore glucose homeostasis in the Scly KO mice.METHODSThree-weeks old male and female Scly KO mice were fed in separate experiments a diet containing 45 % kcal fat and either sodium selenite or a mixture of sodium selenite and selenomethionine (selenite/SeMet) at moderate (0.25 ppm) or high (0.5–1 ppm) levels for 9 weeks, and assessed for metabolic parameters, oxidative stress and expression of selenoproteins.RESULTSSe supplementation was unable to prevent obesity and elevated epididymal white adipose tissue weights in male Scly KO mice. Serum glutathione peroxidase activity in Scly KO mice was unchanged regardless of sex or dietary Se intake; however, supplementation with a mixture of selenite/SeMet improved oxidative stress biomarkers in the male Scly KO mice.CONCLUSIONThese results unveil sex- and selenocompound-specific regulation of energy metabolism after the loss of Scly, pointing to a role of this enzyme in the control of whole-body energy metabolism regardless of Se levels.     

Regulation and function of avian selenogenome

Background

Selenium (Se) is an essential micronutrient required by avian species. Dietary Se/vitamin E deficiency induces three classical diseases in chicks: exudative diathesis, nutritional pancreatic atrophy, and nutritional muscular dystrophy.

Selenium prevents downregulation of antioxidant selenoprotein genes by methylmercury

Selenium (Se) is an essential nutrient required by Se-dependent proteins, termed selenoproteins. The selenoprotein family is small but diverse and includes key proteins in antioxidant, redox signaling, thyroid hormone metabolism, and protein folding pathways. Methylmercury (MeHg) is a toxic environmental contaminant that affects seafood safety. Selenium can reduce MeHg toxicity, but it is unclear how selenoproteins are affected in this interaction. In this study we explored how Se and MeHg interact to affect the mRNA expression of selenoprotein genes in whole zebrafish (Danio rerio) embryos. Embryos were obtained from adult zebrafish fed MeHg with or without elevated Se in a 2×2 factorial design. The embryo mRNA levels of 30 selenoprotein genes were then measured. These genes cover most of the selenoprotein families, including members of the glutathione peroxidase (GPX), thioredoxin reductase, iodothyronine deiodinase, and methionine sulfoxide reductase families, along with selenophosphate synthetase 2 and selenoproteins H, J-P, T, W, sep15, fep15, and fam213aa. GPX enzyme activity and larval locomotor activity were also measured. We found that around one-quarter of the selenoprotein genes were downregulated by elevated MeHg. These downregulated genes were dominated by selenoproteins from antioxidant pathways that are also susceptible to Se-deficiency-induced downregulation. MeHg also decreased GPX activity and induced larval hypoactivity. Elevated Se partially prevented MeHg-induced disruption of selenoprotein gene mRNA levels, GPX activity, and larval locomotor activity. Overall, the MeHg-induced downregulation and subsequent rescue by elevated Se levels of selenogenes regulated by Se status suggest that Se deficiency is a contributing factor to MeHg toxicity.     

Selenium Deficiency Influences Nitric Oxide and Selenoproteins in Pancreas of Chickens

Selenium (Se) deficiency induces pancreatic atrophy in chickens, but the molecular mechanism remains unclear. In this study, we investigated the effect of dietary Se deficiency on the expressions of 25 selenoproteins and the content of nitric oxide (NO) and examined the relationship between selenoproteins and NO. Chickens (180; 1 day old) were randomly divided into two groups, low (L) group (fed with Se deficient (Se 0.033 mg/kg) diet) and control (C) group (fed with normal (Se 0.2 mg/kg) diet). Then, pancreas was collected at 15, 25, 35, 45, and 55 days, and the content of NO, the activity of inducible NO synthase (iNOS), and the messenger RNA (mRNA) levels of 25 selenoproteins and iNOS were measured. The results showed that 25 selenoproteins were decreased (P?P?Thioredoxin reductase 2 (TXNRD2), glutathione peroxidase 1 (GPX1), glutathione peroxidase 3 (GPX3), selenoprotein I (SELI), iodothyronine deiodinase 1 (DIO1), selenoprotein P1 (SEPP1), selenoprotein W1 (SEPW1), selenoprotein O (SELO), selenoprotein T (SELT), selenoprotein M (SELM), selenoprotein X1 (SEPX1), and SPS2 were excessively decreased (P?iNOS activity, and mRNA level were increased strikingly compared with C group (P?相似文献   

Effects of Se-depletion on glutathione peroxidase and selenoprotein W gene expression in the colon

Selenium (Se)-containing proteins have important roles in protecting cells from oxidative damage. This work investigated the effects of Se-depletion on the expression of the genes encoding selenoproteins in colonic mucosa from rats fed diets of different Se content and in human intestinal Caco-2 cells grown in Se-adequate or Se-depleted culture medium. Se-depletion produced statistically significant (P<0.05) falls in glutathione peroxidase (GPX) 1 mRNA (60-83%) and selenoprotein W mRNA (73%) levels, a small but significant fall in GPX4 mRNA (17-25%) but no significant change in GPX2. The data show that SelW expression in the colon is highly sensitive to Se-depletion.     

Beneficial antioxidant status of piglets from sows fed selenomethionine compared with piglets from sows fed sodium selenite

BackgroundStudies in mammals proved dietary organic selenium (Se) being superior to inorganic Se regarding effects on growth performance, antioxidative status, immune response, and Se homeostasis. However, the picture of possible effects of different Se sources and – levels can be expanded. The present field study evaluated the effects on weight gain, hematological and selected biochemical variables as well as plasma concentrations of vitamin E (vitE), total Se and selenobiomolecules in piglets throughout the suckling period.MethodsPiglets were monitored from birth to 38 days of age (d). The mother sows’ diets were enriched with l-selenomethionine (SeMet-0.26 and -0.43 mg Se/kg feed) or sodium selenite (NaSe-0.40 and -0.60 mg Se/kg feed) from 1 month prior to farrowing until the end of lactation period. Piglets received pelleted feed supplemented with Se similarly to the sows’ diets from one week of age. Selenite at 0.40 mg Se/kg (NaSe-0.40) represents a common Se source and -level in pig feed and served as control diet.ResultsFrom 24d, piglets in SeMet-groups had higher mean body weight (BW) compared with piglets from sows fed NaSe-0.40. Furthermore, from five-d and above, piglets from sows fed NaSe-0.60 had significantly higher BW than offspring from sows fed NaSe-0.40. Neonatal piglets in group SeMet-0.43 had significantly lower red blood cell counts (RBC), hemoglobin (Hgb) and hematocrit (Hct) concentrations compared with piglets from sows fed with NaSe-0.40. Neonatal and 5d-old piglets in group SeMet-0.26 showed higher gamma-glutamyl transferase activity than piglets in group NaSe-0.40. From five d and above, group NaSe-0.60 excelled with increased specific hematological variables culminating at age 38d with increased Hct, mean corpuscular volume (MCV), and MC hemoglobin (MCH) as well as increased activities of aspartate transaminase and lactate dehydrogenase compared with the other groups. Generally, offspring in the SeMet groups had higher total Se-concentrations in plasma than those from sows fed selenite, and showed a dose-response effect on plasma Se-concentrations. Furthermore, SeMet-fed piglets had higher plasma levels of the selenoproteins (Sel) glutathione peroxidase 3 (GPx3) and SelP as well as selenoalbumin. Plasma vitE levels were significantly negatively correlated with RBC throughout trial period.ConclusionsMaternal supplementation with SeMet during gestation influenced hematology and clinical biochemistry in neonatal piglets in a different way than in offspring from sows receiving selenite enriched diets. Growth performance was positively influenced by both dietary Se source and Se level. Higher plasma levels of GPx3 observed in piglets receiving SeMet probably improved the protection against birth or growth related oxidative stress. These might prime the piglets for demanding situations as indicated by higher weight gain in offspring from sows fed with SeMet-supplemented diets. Our results on some enzyme activities might indicate that piglets fed NaSe-0.60 had to cope with increased levels of oxidative stress compared with those originating from sows fed SeMet or lower dietary levels of selenite. We assume that combining inorganic and organic Se sources in complete feed for breeding sows might be beneficial fro reproduction and the offspring’s performance.     

Chemical Form of Selenium Affects Its Uptake,Transport, and Glutathione Peroxidase Activity in the Human Intestinal Caco-2 Cell Model

Determining the effect of selenium (Se) chemical form on uptake, transport, and glutathione peroxidase activity in human intestinal cells is critical to assess Se bioavailability at nutritional doses. In this study, we found that two sources of L-selenomethionine (SeMet) and Se-enriched yeast each increased intracellular Se content more effectively than selenite or methylselenocysteine (SeMSC) in the human intestinal Caco-2 cell model. Interestingly, SeMSC, SeMet, and digested Se-enriched yeast were transported at comparable efficacy from the apical to basolateral sides, each being about 3-fold that of selenite. In addition, these forms of Se, whether before or after traversing from apical side to basolateral side, did not change the potential to support glutathione peroxidase (GPx) activity. Although selenoprotein P has been postulated to be a key Se transport protein, its intracellular expression did not differ when selenite, SeMSC, SeMet, or digested Se-enriched yeast was added to serum-contained media. Taken together, our data show, for the first time, that the chemical form of Se at nutritional doses can affect the absorptive (apical to basolateral side) efficacy and retention of Se by intestinal cells; but that, these effects are not directly correlated to the potential to support GPx activity.     

Selenium metabolism and glutathione peroxidase activity in cultured human lymphoblasts

The metabolism of selenite, selenocysteine (SeCys), and selenomethionine (SeMet) was studied in three human lymphoblast cell lines with defects in the transsulfuration pathway and in control cells without this defect. There were very little differences in the induction of glutathione peroxidase (GPX) activity by selenite and SeCys among these cells. However, markedly higher levels of SeMet were required to induce GPX activity in transsulfuration defective cells than in control cells. Surprisingly, the addition of pyridoxal phosphate (PLP) to the media resulted in elevated GPX activity in all cells regardless of the chemical form of Se used. There is no explanation for this effect of PLP, but it is not through direct reaction with GPX or on the alteration of sulfhydryl groups.     

Differential effects of selenium and knock-down of glutathione peroxidases on TNFα and flagellin inflammatory responses in gut epithelial cells

Selenium (Se) is essential for human health. Despite evidence that Se intake affects inflammatory responses, the mechanisms by which Se and the selenoproteins modulate inflammatory signalling, especially in the gut, are not yet defined. The aim of this work was to assess effects of altered Se supply and knock-down of individual selenoproteins on NF-κB activation in gut epithelial cells. Caco-2 cells were stably transfected with gene constructs expressing luciferase linked either to three upstream NF-κB response elements and a TATA box or only a TATA box. TNFα and flagellin activated NF-κB-dependent luciferase activity and increased IL-8 expression. Se depletion decreased expression of glutathione peroxidase1 (GPX1) and selenoproteins H and W and increased TNFα-stimulated luciferase activity, endogenous IL-8 expression and reactive oxygen species (ROS) production. These effects were not mimicked by independent knock-down of either GPX1, selenoprotein H or W; indeed, GPX1 knock-down lowered TNFα-induced NF-κB activation and did not affect ROS levels. GPX4 knock-down decreased NF-κB activation by flagellin but not by TNFα. We hypothesise that Se depletion alters the pattern of expression of multiple selenoproteins that in turn increases ROS and modulates NF-κB activation in epithelial cells, but that the effect of GPX1 knock-down is ROS-independent.     

Selenoprotein expression is regulated at multiple levels in prostate cells

Selenium supplementation in a population with low basal blood selenium levels has been reported to decrease the incidence of several cancers including prostate cancer. Based on the clinical findings, it is likely that the antioxidant function of one or more selenoproteins is responsible for the chemopreventive effect, although low molecular weight seleno-compounds have also been posited to selectively induce apoptosis in transformed cells. To address the effects of selenium supplementation on selenoprotein expression in prostate cells, we have undertaken an analysis of antioxidant selenoprotein expression as well as selenium toxicity in non-tumorigenic prostate epithelial cells （RWPE- 1 ） and prostate cancer cells （LNCaP and PC-3）. Our results show that two of the glutathione peroxidase family members （GPX1 and GPX4） are highly induced by supplemental selenium in prostate cancer cells but only slightly induced in RWPE-1 cells. In addition, GPX 1 levels are dramatically lower in PC-3 cells as compared to RWPE- 1 or LNCaP cells. GPX2 protein and mRNA, however, are only detectable in RWPE-1 cells. Of the three selenium compounds tested （sodium selenite, sodium selenate and selenomethionine）, only sodium selenite shows toxicity in a physiological range of selenium concentrations. Notably and in contrast to previous studies, RWPE-1 cells were significantly more sensitive to selenite than either of the prostate cancer cell lines. These results demonstrate that selenoproteins and selenium metabolism are regulated at multiple levels in prostate cells.     

Selenium and copper status - potential signposts for neurological remission after traumatic spinal cord injury

IntroductionTraumatic Spinal Cord Injury (TSCI) is a severe incident resulting in loss of motor and sensory function caused by complex pathological mechanisms including massive oxidative stress and extensive inflammatory processes. The essential trace elements selenium (Se) and copper (Cu) play crucial roles as part of the antioxidant defense.HypothesisRemission after TSCI is associated with characteristic dynamics of early changes in serum Cu and Se status.Study designSingle-center prospective observational study.Patients and methodsSerum samples from TSCI patients were analyzed (n = 52); 21 recovered and showed a positive abbreviated injury score (AIS) conversion within 3 months (G1), whereas 21 had no remission (G0). Ten subjects with vertebral fractures without neurological impairment served as control (C). Different time points (at admission, and after 4, 9, 12, and 24 h) were analyzed for total serum Se and Cu concentrations by total reflection X-ray fluorescence, and for Selenoprotein P (SELENOP) and Ceruloplasmin (CP) by sandwich ELISA.ResultsAt admission, CP and SELENOP concentrations were higher in the remission group (G1) than in the non-remission group (G0). Within 24 h, there were marginal changes in Se, SELENOP, Cu and CP concentrations in the groups of controls (C) and G0. In contrast, these parameters decreased significantly in G1. Binary logistic regression analysis including Cu and Se levels at admission in combination with Se and CP levels after 24 h allowed a prediction for potential remission, with an area under the curve (AUC) of 87.7% (CI: 75.1%–100.0%).ConclusionThese data indicate a strong association between temporal changes of the Se and Cu status and the clinical outcome after TSCI. The dynamics observed may reflect an ongoing redistribution of the trace elements in favor of a better anti-inflammatory response and a more successful neurological regeneration.     

Metabolism of selenomethionine and effects of interacting compounds by mammalian cells in culture

Since differences have been found in animals, the efficacies of selenomethionine (SeMet), selenite, and selenocystine (SeCys) for glutathione peroxidase (GPx) induction and cellular incorporation were compared and some effects of interacting nutrients on SeMet utilization were examined in tissue cultures. In three cell lines, Chang liver cells, mouse myoblasts and human fibroblasts, selenite was more effective than SeMet for GPx induction. However, radiotracer studies showed that SeMet was more rapidly incorporated into all cells than either selenite or SeCys. Chromatography of acid hydrolysates of Chang liver cells grown with 75Se-labeled SeMet indicated that approximately 90% of incorporated 75Se remained as SeMet, and less than 10% was as SeCys, the form of Se in GPx. Selenite supplementation slightly reduced both the incorporation of 75SeMet and the proportion of cellular 75Se recoverable as SeCys in Chang liver cells. Supplementation with L-methionine, however, significantly reduced 75SeMet incorporation, but significantly increased the proportion of cellular 75Se recovered as SeCys. L-cystine supplementation had no effect on either the cellular incorporation of 75SeMet or the proportion of cellular 75Se recovered as SeCys. These studies of SeMet utilization and effects of interacting nutrients are reflective of observations on SeMet metabolism in whole animals and humans.     

Copper and selenium status as biomarkers of neonatal infections

Neonatal infections are a major risk factor for neonatal mortality. A reliable diagnosis of early-onset sepsis (EOS) is hampered by the variable clinical presentations of the children. We hypothesized that changes in the Se or Cu status, or the biomarkers selenoprotein P (SELENOP) or ceruloplasmin (CP) alone or in combination may be informative of EOS.We generated a new human CP-specific non-competitive immunoassay (ELISA) suitable of analysing small sample volumes and validated the method with a commercial CP source. Using this novel CP assay, we analysed a case-control study of EOS (n = 19 control newborns, n = 18 suspected cases). Concentrations of Se, Cu, SELENOP, CP, interleukin-6 (IL-6), and C-reactive protein (CRP) along with the Cu/Se and CP/SELENOP ratios were evaluated by correlation analyses as biomarkers for EOS. Diagnostic value was estimated by receiver operating characteristic (ROC) curve analyses.The new CP-ELISA displayed a wide working range (0.10–6.78 mg CP/L) and low sample requirement (2 μL of serum, EDTA-, heparin- or citrate-plasma). Plasma CP correlated positively with Cu concentrations in the set of all samples (Pearson r = 0.8355, p < 0.0001). Three of the infected neonates displayed particularly high ratios of Cu/Se and CP/SELENOP, i.e., 3.8- to 6.9-fold higher than controls. Both the Cu/Se and the CP/SELENOP ratios correlated poorly with the early infection marker IL-6, but strongly and positively with the acute-phase protein CRP (Cu/Se-CRP: Spearman ϱ = 0.583, p = 0.011; CP/SELENOP-CRP: ϱ = 0.571, p = 0.013). The ROC curve analyses indicate that a combination of biomarkers for the Se and Cu status do not improve the early identification of EOS considerably.This study established a robust, highly precise, partly validated and scalable novel CP sandwich ELISA suitable for basic and clinical research, requiring minute amounts of sample. The ratio of circulating CP/SELENOP constitutes a promising new composite biomarker for detection of EOS, at least in a subset of severely diseased children.     

Glutathione peroxidase-1 gene knockout on body antioxidant defense in mice

To determine the in vivo role of cellular glutathione peroxidase (E.C.1.11.1.9, GPX1), we challenged the GPX1 knockout [GPX1(-/-)], the GPX1 overexpressing [GPX1(+)], and their respective wild-type (WT) mice of different Se and vitamin E status with acute oxidative stress. After these mice were injected with pro-oxidants paraquat or diquat at 12 to 125 mg/kg of body weight, their survival rate and time were a function of their GPX1 activity levels. The GPX1 protection was associated with attenuation of NADPH and NADH oxidation, protein carbonyl and F(2)-isoprostanes formation, and alanine transaminase release in various tissues, and was irreplaceable by high levels of dietary vitamin E or other selenoproteins. The GPX1 expression was also protective against moderate oxidative stress induced by low levels of paraquat or diquat, particularly in the Se-deficient mice. Alteration of GPX1 expression showed no impact on the expression of other selenoproteins and antioxidant enzymes in unstressed mice. Total Se content in liver of the Se-adequate GPX1(-/-) mice was reduced by 60% the WT controls. In conclusion, normal expression of GPX1 is essential and overexpression of GPX1 is beneficial to protect mice against acute oxidative stress.     

Characterization and tissue expression of twelve selenoproteins in yellow catfish Pelteobagrus fulvidraco fed diets varying in oxidized fish oil and selenium levels

BackgroundSelenium (Se) functions through selenoproteins and is essential to growth and metabolism of vertebrates. The present study was conducted to identify twelve selenoproteins genes (selenoe, selenof, selenoh, selneoi, selenom, selenok, selneon, selenoo, selenot, selenos, selenou and msrb1) from yellow catfish. Their mRNA expression patterns, as well as their response to dietary oxidized fish oils and Se addition were explored.MethodsWe use 3′and 5′ RACE PCR to clone full-length cDNA sequence of twelve selenoprotein genes from yellow catfish. Their mRNA expression patterns were assessed via quantitative real-time PCR. Yellow catfish were fed diet adequate Se+ fresh fish oil, adequate Se+ oxidized fish oil, high Se+ fresh fish oil and high Se+ oxidized fish oil, respectively, for 10 weeks. Their kidney, heart, brain and testis were used to assess the mRNA expression of twelve selenoprotein.ResultsTwelve selenoprotein genes had similar domains with mammals and the other fish. Their mRNAs were expressed widely in eleven tissues but varied with the tissues. Dietary oxidized fish oils and Se addition influenced their mRNA abundances of twelve selenoproteins in a tissue-dependent manner.ConclusionOur study demonstrated the characterization and expression of twelve selenoproteins, and elucidated their responses in yellow catfish fed diets varying in oxidized fish oils and Se addition, which increased our knowledge into the biological function and regulatory mechanism of Se and selenoproteins in fish.     

A Selenium-deficient Caco-2 Cell Model for Assessing Differential Incorporation of Chemical or Food Selenium into Glutathione Peroxidase

Assessing the ability of a selenium (Se) sample to induce cellular glutathione peroxidase (GPx) activity in Se-deficient animals is the most commonly used method to determine Se bioavailability. Our goal is to establish a Se-deficient cell culture model with differential incorporation of Se chemical forms into GPx, which may complement the in vivo studies. In the present study, we developed a Se-deficient Caco-2 cell model with a serum gradual reduction method. It is well recognized that selenomethionine (SeMet) is the major nutritional source of Se; therefore, SeMet, selenite, or methylselenocysteine (SeMSC) was added to cell culture media with different concentrations and treatment time points. We found that selenite and SeMSC induced GPx more rapidly than SeMet. However, SeMet was better retained as it is incorporated into proteins in place of methionine; compared with 8-, 24-, or 48-h treatment, 72-h Se treatment was a more sensitive time point to measure the potential of GPx induction in all tested concentrations. Based on induction of GPx activity, the cellular bioavailability of Se from an extract of selenobroccoli after a simulated gastrointestinal digestion was comparable with that of SeMSC and SeMet. These in vitro data are, for the first time, consistent with previous published data regarding selenite and SeMet bioavailability in animal models and Se chemical speciation studies with broccoli. Thus, Se-deficient Caco-2 cell model with differential incorporation of chemical or food forms of Se into GPx provides a new tool to study the cellular mechanisms of Se bioavailability.     

Effects of Dietary Selenium Deficiency on mRNA Levels of Twenty-One Selenoprotein Genes in the Liver of Layer Chicken

Selenium (Se) is an essential trace element in many life forms due to its occurrence as selenocysteine (Sec) residue in selenoproteins. However, little is known about the expression pattern of selenoproteins in the liver of layer chicken. To investigate the effects of Se deficiency on the mRNA expressions of selenoproteins in the liver tissue of layer chickens, 1-day-old layer chickens were randomly allocated into two groups (n?=?120/group). The Se-deficient group (?Se) was fed a Se-deficient corn–soy basal diet; the Se-adequate group as control (+Se) was fed the same basal diet supplemented with Se at 0.15 mg/kg (sodium selenite). The liver tissue was collected and examined for mRNA levels of 21 selenoprotein genes at 15, 25, 35, 45, 55, and 65 days old. The data indicated that the mRNA expressions of Gpx1, Gpx2, Gpx3, Gpx4, Sepn1, Sepp1, Selo, Sepx1, Selu, Txnrd1, Txnrd2, Txnrd3, Dio1, Dio2, SPS2, Selm, SelPb, Sep15, and Sels were decreased (p?<?0.05), but not the levels of Dio3 and Seli (p?>?0.05). The results showed that the mRNA levels of 19 selenoprotein (except Seli and Dio3) genes in the layer chicken liver were regulated by diet Se level. The present study provided some compensated data about the roles of Se in the regulation of selenoproteins.