视黄醇结合蛋白(RBP)及基因在养猪生产中的应用

视黄醇结合蛋白(RBP)是体内一种低分子量的载体蛋白,在酸性环境中较为稳定。自从1968年Kanai等首次分离发现RBP后,已在猪、牛、绵羊等家畜中进行了广泛研究。RBP在协助维生素A(V i-tA)发挥生理功能中起着重要作用。RBP能特异性地与视网膜上皮组织结合,为其提供V itA,完成转运V itA至靶细胞后,即与前白蛋白分离,迅速通过肾小球滤过膜,在肾近曲小管被吸收分解,吸收率可达99.97%。在孕酮诱导下,猪子宫内膜会分泌视黄醇结合蛋白,这些蛋白有四种结构形式,分别为RBP1、RBP2、RBP3和RBP4。本文主要就RBP及基因在养猪生产中的应用作一…     

视黄醇结合蛋白4的生物学作用研究进展

视黄醇结合蛋白(Retinol-binding protein,RBP)是一类疏水性运载蛋白,其中的视黄醇结合蛋白4(RBP4)是目前已经证实的唯一一类可在血液中转运视黄醇的蛋白。RBP4在机体的各个脏器中均有表达,肝脏为主要表达场所,视黄醇在家禽繁殖过程中起到一定的促进作用,而RBP4参与视黄醇的存储、代谢和吸收过程。文章针对RBP4对家禽繁殖性能影响方面的研究进展进行论述,以初步揭示该蛋白与家禽繁殖性能之间的关系。     

视黄醇结合蛋白4基因调控动物繁殖性能的研究进展

视黄醇结合蛋白4(RBP4)是孕体产生的主要蛋白质之一,也是动物体内唯一一种能够在血液中运载维生素A的转运蛋白,在协助视黄醇发挥生理作用中至关重要。文章介绍了RBP4基因在动物胚胎发育、产仔性能、睾丸功能和精液品质等方面的重要作用,并对RBP4基因多态性与动物繁殖性能的关系进行了阐述,以期为RBP4相关研究提供参考。     

视黄醇结合蛋白4基因与母猪繁殖性能相关性的研究进展

视黄醇结合蛋白4(Retinol Binding Protein 4,RBP4)是动物体内低分子量细胞外视黄醇的主要疏水转运蛋白,对母猪繁殖性能和胚胎发育过程起到一定的促进作用。RBP4在辅助视黄醇发挥其生理功能过程中起着不可替代的作用。本文综述了RBP4基因对母猪繁殖性能的影响,旨在为母猪选种、育种等繁殖性能的研究提供参考依据。     

视黄醇结合蛋白(RBP)及其基因在猪中的研究进展

本文综述了视黄醇结合蛋白(RBP)的生物学作用和作用机理,RBP基因的结构和在猪中的染色体定位,以及与猪繁殖性能的关系。     

视黄醇结合蛋白4(RBP4)基因多态性对猪繁殖性能的影响

视黄醇结合蛋白4(RBP4)是动物体内一种重要的转运蛋白,它在介导维生素A及其代谢物生理功能的正常发挥中起着不可替代的作用。RBP4是孕体产生的主要蛋白之一,对动物的胚胎发育和繁殖性能有较显著的影响。近年来,RBP4基因作为猪产仔数候选基因在国内外开展了广泛的研究。文章综述了RBP4基因的结构与定位、RBP4的生物学功能,以及RBP4基因多态性对猪繁殖性能的影响,重点讨论了RBP4基因多态性对猪产仔数的影响,并对RBP4基因研究中存在的问题和前景进行了展望,为进一步阐明其遗传机理和后续研究提供理论参考和实践帮助。     

血清视黄醇结合蛋白和维生素A浓度与1月龄仔猪体重关系的研究

采用ELISA法和HPLC法检测了56头1月龄仔猪血清中视黄醇结合蛋白(RBP)和维生素的含量,并用SASV6.12软件对所获得数据进行了统计分析。结果表明:RBP和维生素的含量在不同体重组间无差异(P>0.05),而在不同窝间存在差异(P<0.05);血清中RBP和维生素的含量存在显著正相关(P<0.01);维生素的含量与1月龄仔猪体重存在显著正相关(P<0.01)。可以考虑将RBP的检测结果作为一个评价仔猪营养状况的指标。     

家畜视黄醇结合蛋白4（RBP4）的研究进展

视黄醇结合蛋白4（retinol-binding proteins 4,RBP4）是由孕酮受体产生的重要蛋白质,其促进转化生长因子（TGF）的表达,参与胚胎的早期发育。此外,RBP4还具有参与VA转运等功能。RBP4基因是影响家畜繁殖性能的候选基因,现已在绵羊、猪、牛和其他家畜中进行了广泛研究。综述了家畜RBP4基因的作用和近年来国内外的相关研究进展。     

RBP4基因与动物繁殖性能的相关性

视黄醇结合蛋白4(RBP4)是动物体内一种重要的转运蛋白,它在介导维生素A及其代谢物生理功能的正常发挥中起着不可替代的作用。RBP4是孕体产生的主要蛋白之一,对动物的胚胎发育和繁殖性能有较显著的影响。RBP4的功能障碍会导致维生素A的储存、转运、分布及代谢的异常,进而引发各种疾病,并影响上皮、骨组织的生长、分化与繁殖、胚胎发育。本文综述了RBP4基因的结构与定位,RBP4的生物学功能,以及RBP4基因与动物繁殖性能的关系。     

视黄醇结合蛋白4基因多态性对长自猪繁殖性能的影响

通过PCR-RFLP技术对长白猪视黄醇结合蛋白4（Retinol binding protein4，RBP4）基因进行多态性检测，并分析其对产仔数的影响。结果表明，在长白初产和经产母猪中，RBP4基因有利基因型为AA基因型，AA型在总产仔数和产活仔数方面均高于AB型、阻型，其中总产仔数显著高于AB型（P〈0．05），产活仔数显著高于BB型（P〈0．05）各基因型之间断奶窝重与初生窝重差异不显著。     

Characterisation of transthyretin and retinol-binding protein in plasma and cerebrospinal fluid of dogs

The aim of this study was to investigate differences in concentrations of vitamin A, transthyretin (TTR) and retinol-binding protein (RBP) between plasma and cerebrospinal fluid (CSF) in dogs. RBP was detected using ELISA, and both RBP and TTR by Western blot analysis after separation on SDS-PAGE. Vitamin A was determined by high performance liquid chromatography. RBP and TTR as well as vitamin A were detected in all samples but at substantially lower concentrations in CSF compared to plasma. RBP in dog plasma showed a similar molecular mass to that of humans, whereas canine TTR had a lower molecular mass. Comparison between plasma and CSF showed that both RBP and TTR were of lower molecular mass in CSF. In CSF, RBP and retinol were present at 10-100-fold lower concentrations compared to plasma. Retinyl esters were present only in minute amounts in 5/17 samples. In conclusion, the CSF of dogs compared to humans is significantly different in terms of both quality and quantity of transport proteins for vitamin A.     

Effects of chronic renal disease on the transport of vitamin A in plasma and urine of dogs

OBJECTIVE: To determine plasma and urine concentrations of retinol, retinyl esters, retinol-binding protein (RBP), and Tamm-Horsfall protein (THP) in dogs with chronic renal disease (CRD). ANIMALS: 17 dogs with naturally developing CRD and 21 healthy control dogs. PROCEDURE: A diagnosis of CRD was established on the basis of clinical signs, plasma concentrations of creatinine and urea, and results of urinalysis. Concentrations of retinol and retinyl esters were measured by use of reverse-phase high-performance liquid chromatography. Concentrations of RBP and THP were measured by use of sensitive ELISA systems. RESULTS: Dogs with CRD had higher plasma concentrations of retinol, which were not paralleled by differences in plasma concentrations of RBP. Calculated ratio of urinary total vitamin A (sum of concentrations of retinol and retinyl esters to creatinine concentration) and ratio of the concentration of urinary retinyl esters to creatinine concentration did not differ between groups. However, we detected a significantly higher retinol-to-creatinine ratio in the urine of dogs with CRD, which was paralleled by a higher urinary RBP-to-creatinine ratio. Thus, in dogs with CRD, the estimated fractional clearance of total vitamin A, retinol, and RBP was increased. Furthermore, dogs with CRD had a reduced urinary THP-to-creatinine ratio. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study documented that CRD affects the concentrations of retinol in plasma and urine of dogs. Analysis of the data indicates that measurement of urinary RBP and urinary THP concentrations provides valuable information that can be helpful in follow-up monitoring of dogs with CRD.     

Levels of retinol and retinyl esters in plasma and urine of dogs with urolithiasis

Vitamin A (VA) deficiency and Tamm-Horsfall glycoprotein (THP), a protein that binds retinol and retinyl esters in canine urine, might be involved in the pathogenesis of urolithiasis in dogs. In the present study, we assessed levels of retinol, retinyl esters, retinol-binding protein (RBP) and THP in plasma and urine of dogs with a history of urolithiasis (n = 25) compared with clinically healthy controls (n = 18). Plasma retinol concentrations were higher in dogs with uroliths of struvit (P < 0.01), calcium oxalate (P < 0.05), urate (P < 0.01) and cysteine, but there were no differences in the concentrations of plasma RBP and retinyl esters. Excretion of urinary retinol and retinyl esters were tentatively, but not significantly higher in the stone-forming groups, which was accompanied by increased levels of urinary RBP (P < 0.01) and lower excretions in THP (P < 0.01). The results show that VA deficiency may be excluded as a potential cause for canine urolithiasis. However, the occurrence of RBP and a concomitant reduction of THP in urine indicates a disturbed kidney function as cause or consequence of stone formation in dogs.     

Immunochemical Localization of Megalin,Retinol-binding protein and Tamm–Horsfall Glycoprotein in the Kidneys of Dogs

Megalin, retinol-binding protein (RBP) and Tamm–Horsfall glycoprotein (THP) are involved in the renal metabolism of vitamin A in canine species. The presence of megalin, RBP and THP in the kidneys of dogs was investigated using immunohistochemical methods. Megalin was highly expressed in the apical membrane of the proximal convoluted and straight tubule cells. Immunoreactive RBP was detected below the apical plasma membrane, as well as in basolateral granules of the proximal convoluted tubule cells. THP immunoreactivity was seen in the epithelial cells lining the thick ascending limb of the loop of Henle. Furthermore, THP was displayed in a scattered pattern within the distal convoluted tubules. The co-localization of megalin and RBP coincides with biochemical studies that have shown megalin to be responsible for renal RBP absorption in the proximal convoluted tubules after filtration through the renal glomerulus. The presence of THP, the carrier for vitamin A in canine urine, showed that vitamin A excretion in the urine of dogs is not merely a filtration process but also seems to be a pathway located in the distal part of the nephron.     

The distribution of vitamin A and retinol-binding protein in the blood plasma, urine, liver and kidneys of carnivores

The contents of retinol and retinyl esters as well as retinol-binding protein (RBP) in the plasma, urine, liver and kidneys of dogs, raccoon dogs and silver foxes were investigated. In the plasma and urine of all three species, vitamin A was present as retinol and retinyl esters. Vitamin A levels (1376+/-669 microg x g(-1)) were significantly higher in the livers of dogs than in the kidneys (200+/-217 microg x g(-1), P < 0.001 ). However, vitamin A levels in the kidneys of raccoon dogs (291+/-146 microg x g(-1)) and silver foxes (474+/-200 microg x g(-1)) were significantly higher than in the liver (67+/-58 microg x g(-1) and 4.3+/-2.4 microg x g(-1), respectively, both P < 0.001). RBP was immunologically detected in the blood plasma of all species, but never in the urine. In the liver, immunoreactive RBP was found in hepatocytes. In the kidneys of all species, RBP was observed in the cells of the proximal convoluted tubules. The levels of vitamin A in the livers of raccoon dogs and silver foxes were extremely low, which would be interpreted as a sign of great deficiency in humans. This observation might indicate that the liver status cannot be used as an indicator of vitamin A deficiency in canines. The high levels of vitamin A in the kidneys in all three species may indicate a specific function of the kidney in the vitamin A metabolism of canines.     

Purification and properties of porcine allantoic fluid retinol-binding protein

Retinol-binding protein (RBP) was purified from Day 60 porcine allantoic fluid by a combination of diethylaminoethyl cellulose, G-100 Sephadex, G-50 Sephadex, Phenyl-Sepharose, and Reactive Green 19-dye-agarose chromatography. The yield was 1 to 2 mg of RBP, which generated a single M_r 20,000 band after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and up to four isoelectric variants (isoelectric variants 1 to 4) after two-dimensional PAGE (2D-PAGE). The protein cross-reacted with antiserum raised against human RBP. When incubated with [³H]retinol and subjected to G-100 Sephadex chromatography, [³H]retinol coeluted with the protein. These results indicate that the purified protein is an RBP. When purified RBP was subjected to native 2D-PAGE, six forms of RBP were observed. Three native forms were fluorescent, and three were not fluorescent, suggesting that these forms were RBP with and without retinol, respectively. Denaturing 2D-PAGE analysis of each native form of RBP suggested that two of the nonfluorescent and two of the fluorescent native forms of RBP corresponded to isoelectric variant 1 on denaturing 2D-PAGE, whereas the other fluorescent and nonfluorescent forms corresponded to isoelectric variant 2. The incubation of RBP with 50 μM retinol enhanced the amount of both isoelectric variants present as fluorescent RBP, but uptake by isoelectric variant 1 was greater than that by isoelectric variant 2. These data indicate that RBP can be purified from porcine allantoic fluid and suggest that the isoelectric variants may differ in their affinity for retinol.     

Production of monoclonal antibodies and enzyme immunoassay to bovine retinol-binding protein and determination of retinol-binding protein serum levels and retinol concentrations in serum and liver in dairy cows before and after parturition

To study vitamin A transport in dairy cows and heifers around parturition, an enzyme immunoassay for bovine retinol binding protein (RBP) was developed and serum levels determined. Serum and liver concentrations of retinol were assayed by HPLC. Four weeks before expected calving the cows and heifers were divided into two groups each, and half of the animals received a protein supplementation during the dry period.The mean serum RBP concentration 4 weeks before calving was 42 mg l-1 for the cows and 44 mg l-1 for the heifers. The serum retinol concentrations were 0.53 mg l-1 for the cows and 0.42 mg l-1 for the heifers, and the liver retinol concentrations 0.30 mg l-1 and 0.13 mg g-1, respectively. In the groups without protein supplementation there was a significant decrease in serum RBP at sampling 1 week before parturition compared to initial values. The measurement of serum RBP may prove useful in assessment of amino acid availability in dairy cows.     

Retinol transport system in cattle and purification of retinol-binding protein from bovine serum

Retinol transport system in cattle was investigated, followed by the purification and characterization of bovine serum retinol-binding protein (RBP). Gel filtration of serum from cow produced two retinol peaks, peak 1 and 2. The major, peak 1 having higher molecular weight corresponded to the retinol peak from human serum which consisted of RBP and prealbumin (PA). The peak 2 which was not presented in the human serum had lower molecular weight (about 20,000). In the presence of 3.0 M urea, the peak 1 was almost disappeared and peak 2 was increased. On the other hand, in the serum from calf, major retinol peak was corresponded to the peak 2 from cow. These results suggested that, in cow, retinol was transported by the complex of RBP and another protein, presumably PA, but in calf, mainly by RBP alone. Purification of bovine RBP was carried out by using four chromatographic steps as follows; 1. DEAE-cellulose (pH 6.0), 2. Sephadex G-100 (using the buffer containing 3.0 M urea), 3. DEAE-cellulose (pH 8.3), 4. Sephadex G-100. From 1,100 ml of serum, 14.1 mg of bovine RBP was finally obtained and the overall recovery was estimated to be about 32%. Its molecular weight, ultraviolet absorption and fluorescence spectra, electrophoretic mobility, and amino acid composition were similar to those of other species.     

Evidence for Effects of Testis and Epididymis Expressed Genes on Sperm Quality and Boar Fertility Traits

Retinol-binding protein 4 (RBP4), androgen receptor (AR), relaxin (RLN), acrosin (ACR) and osteopontin (polymorphism in intron 6 named OPNin6; polymorphism in promoter region named OPNprom) were addressed as functional candidate genes for sperm quality and boar fertility and investigated for their association with sperm concentration, motility, semen volume per ejaculate, plasma droplets rate, abnormal spermatozoa rate as well as non-return rate and number of piglets born alive. Therefore 356 AI boars of the purebred Pietrain (PI) and crossbred Pietrain x Hampshire (PI x HA) were genotyped at these loci. Analysis of variance revealed significant associations of RBP4 (p < 0.05), ACR (p < 0.01), and OPNin6 (p < 0.05) with sperm motility. OPNin6 (p < 0.05) was also associated with number of piglets born alive. Moreover, AR (p < 0.05) and OPNprom (p < 0.05) were significantly associated with abnormal spermatozoa rate. For RLN (p < 0.01) there was evidence for effects on sperm volume and ACR significantly affected sperm concentration (p < 0.05) as well as non-return rate (p < 0.05). No significant effects of any locus on plasma droplets rate were observed.