褪黑激素受体基因的研究进展

褪黑激素通过与药理学特异性的高亲和性G-蛋白耦联受体相结合来发挥其生物学功能。本文介绍了褪黑激素受体的结构、功能与调控、褪黑激素受体基因的克隆及基因结构、褪黑激素受体基因的发育性表达与作用、褪黑激素受体基因的定位与多态性分析,并讨论了该基因与繁殖季节性的关系。 Abstract:Melatonin exerts its biological effects through pharmacological specific,high affinity G protein-coupled receptors.This review introduced the structure,function,and regulation of melatonin receptor,the cloning and structure,developmental expression,mapping and polymorphism of melatonin receptor gene.The relationship between melatonin receptor gene and reproductive seasonality was also discussed.     

猪主要经济性状候选基因的研究进展

随着人类基因组计划的完成和动物基因组计划的进行,许多控制动物经济性状的主基因逐渐被发现,并显示出巨大的应用前景。本文概述了影响猪繁殖、肉质、生长发育等主要经济性状的主基因的基因大小、基因定位和基因效应等,对主基因的研究在动物遗传育种科学发展中的意义也作了一些阐述。 Abstract:With the accomplishment of human genome project and the development of animal genome project,many major genes affecting animal economic traits were gradually detected,and they show great application prospect.Major genes affecting reproductive traits,meat quality traits,growing and developing traits of pig are summarized from their size,location and effect.In addition,the meaning of major gene in the improvement of animal breeding and genetics is also discussed.     

猪雌激素受体基因Pvu II多态性与产仔数性状的关系

雌激素受体（estrogen receptor,ESR）能调控雌激素的合成,影响繁殖功能。将ESR基因作为控制猪产仔数的候选基因,分析其Pvu II多态性与高产猪种莱芜猪和国外引进猪种长白猪产仔数的关系。序列分析发现,PCR扩增区56bp的Pvu II酶切片段位于RFLP分析获得的37kb正向序列的起始部分。因ESR基因在高产仔数的莱芜猪中的Pvu II多态性分布不能证实B基因为优势基因,故推测37kb条带对该猪种产仔数可能不起决定作用。 Abstract:Estrogen receptor (ESR) can regulate the synthesis of oestrogen and affect the reproduction of swine.The relationship between PvuII polymorphisms at estrogen receptor gene and litter size was analyzed in Laiwu breed and Landrace breed by candidate gene method.The results were shown that 56bp of PvuII polymorphisms was the same as the beginning sequence of 37kb of RFLP.The distribution of PvuII polymorphisms also could not prove that B gene was a superior gene,and there was no decisive effect of 37kb band on litter size in pigs.     

黑素皮质素受体1——哺乳动物黑色素形成中的关键基因MC1R——the Key Gene in Mammalian Melanin Synthesis

黑色素的形成与产生在动物的生长发育过程中受到许多基因的调控。本文综述了近年来被广泛研究的哺乳动物黑色素形成调控中的一个关键基因——黑素皮质素受体1（melanocortin-1-receptor, MC1R）基因的作用机制、DNA序列变异与黑色素性状之间的关系,并且对另一重要的脊椎动物类群——鸟类中MC1R基因的确定与突变情况作以概述,此外对乌骨鸡富含黑色素的原因和鸟类的黑色素形成机制也进行了探讨。Abstract: The study of the molecular regulation mechanism of melanin synthesis during animal development has become a new focus recently .The synthesis and production of melanin during animal development are regulated by many genes. This paper summarized the molecular function mechanism of melanocortin-1-receptor (MC1R) gene and the relationship between the consequences of polymorphic variation of the gene and melanin traits, in addition to summarized the identification and mutation of MC1R gene in birds. Furthermore, the reason of abundant melanin in silkies and melanin synthesis mechanism in birds are all also discussed here.     

猪Mu阿片受体基因单核苷酸多态性分析

Mu阿片受体（简称MOR）属于G蛋白藕联受体,分布在痛觉传导区,以及与情绪和行为有关的区域,影响动物的神经反应和行为表现。该研究以长白猪、大白猪和杜洛克猪为试验材料, 用8对引物对Mu阿片受体基因的5′ UTR区域、整个编码区和3′ UTR区域用PCR-SSCP方法进行了扫描,发现5处突变基因座（GenBank登录号：AF521309）。统计结果发现基因型频率分布与品种有关,大白猪突变基因型频率显著高于长白和杜洛克,本研究推测分布上的差异可能是由于长期的选择压力造成的。 Abstract:Mu opioid receptor (MOR) is a member of G protein-coupled receptor family,distributed in the pain transduction region in the brain and related to emotion and behaviour.This study was designed to investigate the Single Nucleotide Polymorphism (SNP) of Mu opioid receptor gene in various breeds,including duroc,landrace and Yorkshire.5′ UTR ( untranslate region),coding region and 3′ UTR of Mu opioid receptor gene were amplified by eight pairs of primers,and the Single Nucleotide Polymorphism (SNP) were detected by SSCP.Five polymorphisms were found (Genebank Accession number:AF521309).The results of χ2 test showed that the frequencies of genotypes in different breeds were significantly different (P＜0.01).The frequencies of mutation genotypes in Yorkshire were significantly higher than Duroc and Landrace.According to the above results,we can speculate the difference of the frequencies of genotypes may be the results of long term choice pressure.     

PCR-RFLP检测LDL受体基因TaqⅠ多态性位点的研究

应用聚合酶链反应(PCR)扩增人类LDL受体基因外显子4-内含子4-外显子5片段,PCR产物为1.55kb,DNA片段经序列鉴定后,进行TaqI酶切位点的RFLP分析。结果显示:中国汉族人群LDL受体基因中存在着TaqⅠ酶切位点多态性; 200个LDL受体等位基因中TaqⅠ酶切位点出现的频率为0.515,该点频率较为适中, 可作为中国汉族人群LDL受体基 因的遗传标志来进行家族性高胆固醇血症(FH)的基因诊断。所建立起的LDL受体基因TaqⅠ位点的PCR -RFLP方法具有快速、简便的特点,在FH的基因诊断上有应用价值。 Abstract:To develop rapid and sensitive technique for detectin the TaqI polymorphism at the human LDL receptor gene in Chinese,the exon4-intron4-exon5 of the human LDL receptor gene was amplified by polymerase chain reaction(PCR).The PCR products were directly analysed by restriction fragment length polymorphisms(RFLP).The results showed that the TaqI polymorphism is associated with the LDL receptor gene in Chinese of Han nationality;The frequency of T= allele (presence of TaqI cutting site)is 0.515 in 200 LDL receptor alleles.This technique may be used for rapid and sensitive screening of the LDL receptor gene for the TaqI polymorphism.     

鸡催乳素基因序列多态及生物信息学分析

选择繁殖性能具有明显差异的4个鸡品种（莱航鸡、阳山鸡、丝羽乌骨鸡和隐性白洛克鸡）构建品种DNA池,采用测序的方法快速筛查鸡催乳素基因（chicken prolactin,cPRL）5′侧翼调控区、外显子区和部分内含子区约4500 bp范围内可能与产蛋性能相关的序列多态,共检测到13个SNPs和两个短片段（24 bp和15 bp）插入/缺失多态,其中在5′侧翼序列筛查到9个SNPs及两个短片段插入/缺失多态,在第2外显子筛查到1个SNP,在第5外显子筛查到两个SNPs,在第2内含子筛查到1个SNP;进一步利用生物信息学分析cPRL基因的5′侧翼调控序列,发现24 bp短片段的插入使莱航鸡比阳山鸡多出了1个Evi-1可能的结合位点（93分）,C-2402T的变异则使阳山鸡比莱航鸡多出了1个C/EBPbeta可能的结合位点（94分）,这两个结合位点是否影响cPRL基因的表达,影响鸡的就巢性和产蛋性能,还需要进一步研究。Abstract：Four chicken breeds (White Leghorn, Yangshan, Taihe Silkies, White Recessive Rocks) with different reproduction were applied to screen potential SNPs related to laying performance in the 5′flanking region, exon region and partial intron region of chicken prolactin (cPRL) gene. Totally almost 4500 bp were screened rapidly based on DNA pooling and sequencing, and thirteen single nucleotide polymorphisms (SNPs) and two indels (24 bp and 15 bp) were found, including nine SNPs and two indels in the 5′flanking region, one SNP in Exon 2, two SNPs in Exon 5 and one SNP in Intron 2 respectively. Furthermore, 5′flanking region of cPRL gene was analyzed by the website of http://motif.genome.ad.jp/. A possible Evi-1 binding site (score 93) was found in White Leghorn cPRL gene because of the 24 bp insertion, another possible C/EBPbeta binding site (score 94) was found in Yangshan cPRL gene because of the variation of C-2402T. Further studies need to be carried out to verify their effects on the expression of cPRL gene, the broodiness and laying performance of chickens.     

PIT-1基因在人、鼠及猪中的研究现状

本文对PIT-1基因在鼠、人及猪中作为生长发育性状候选基因的研究现状作-综述,主要包括PIT-1基因与鼠矮小性状、人类综合性垂体激素缺陷症及猪的生长和胴体性状之间的关系,并对PIT-1基因在小型猪中的研究前景作一展望。 This paper summaries the current study status of PIT-1 gene,which is the candidate gene for growth and development performance.The review mainly includes the association of PIT-1 gene with dwarfism in mice,CPHD in humans and growth and carcass traits in pigs.The research prospect of PIT-1 gene in mini-pig is also discussed.     

黑素皮质激素受体1（MC1R）基因与猪的毛色

猪的真黑色素与褐黑色素的合成量与分布主要受控于黑素皮质激素受体1基因。本文综述了该基因的定位、突变与多态检测,黑素皮质激素受体的作用机制,提出了对黑素皮质激素受体1基因进一步研究的看法。 Abstract：The amount and distribution of eumelanin and phaeomelanin are mainly controlled by Melanocortin Receptor 1 gene.The location、mutation and polymorphism testing of Melanocortin Receptor 1 gene and mechanism of Melanocortin Receptor 1 in pigs are discussed in the paper.The further research about the gene is also suggested.     

Functional consequences of prolactin signalling in endothelial cells: a potential link with angiogenesis in pathophysiology?

Prolactin is best known as the polypeptide anterior pituitary hormone, which regulates the development of the mammary gland. However, it became clear over the last decade that prolactin contributes to a broad range of pathologies, including breast cancer. Prolactin is also involved in angiogenesis via the release of pro-angiogenic factors by leukocytes and epithelial cells. However, whether prolactin also influences endothelial cells, and whether there are functional consequences of prolactin-induced signalling in the perspective of angiogenesis, remains so far elusive. In the present study, we show that prolactin induces phosphorylation of ERK1/2 and STAT5 and induces tube formation of endothelial cells on Matrigel. These effects are blocked by a specific prolactin receptor antagonist, del1-9-G129R-hPRL. Moreover, in an in vivo model of the chorioallantoic membrane of the chicken embryo, prolactin enhances vessel density and the tortuosity of the vasculature and pillar formation, which are hallmarks of intussusceptive angiogenesis. Interestingly, while prolactin has only little effect on endothelial cell proliferation, it markedly stimulates endothelial cell migration. Again, migration was reverted by del1-9-G129R-hPRL, indicating a direct effect of prolactin on its receptor. Immunohistochemistry and spectral imaging revealed that the prolactin receptor is present in the microvasculature of human breast carcinoma tissue. Altogether, these results suggest that prolactin may directly stimulate angiogenesis, which could be one of the mechanisms by which prolactin contributes to breast cancer progression, thereby providing a potential tool for intervention.     

藏猪繁殖性状多基因效应分析

藏猪是我国特有的高原型地方猪种, 具有适应高海拔恶劣气候环境、抗病、耐粗、肉质鲜美等特点, 但繁殖力低。文章以促卵泡素b亚基(FSHb)、雌激素受体(ESR)、促乳素受体(PRLR)和视黄醛结合蛋白4(RBP4)等基因作为繁殖性状主要候选基因, 测定76头藏猪的基因型, 分析单基因和多基因合并对繁殖性状的影响效应。结果说明, 在藏猪群体中, FSHb、ESR和PRLR基因不同基因型繁殖性状差异显著, 优良基因型分别为BB、BB和AA。藏猪RBP4基因只有2种基因型, 对繁殖性状影响不显著。FSHb-ESR-PRLR基因的合并优良基因型为BB-BB-AA, 多基因聚合效应高于单基因效应。     

Expression of the full-length rabbit prolactin receptor and its specific domains in baculovirus infected insect cells

The prolactin receptor is a membrane protein mainly involved in the development of the mammary gland and in lactation in mammals. We used specific cDNA constructs and the insect/baculovirus expression system and produced independently and in large amounts several recombinant forms of the rabbit mammary gland prolactin receptor: the full-length receptor (L1, L2), a truncated membrane form (S), a secretable form of the extracellular domain (E) and two forms of the intracellular domain (I1, I2). Of these forms, the L1 and L2 are associated with the membrane fraction, the E is predominantly secreted into the medium and the I1 and I2 are expressed as soluble proteins and surprisingly, a great portion accumulates in the culture medium. The molecular mass (94 kDa) of the expressed full-length receptor corresponds to the translation product of the entire cDNA coding region. The receptor biochemically identified in the rabbit mammary gland is however much shorter. Thus, in the mammary gland, the receptor presumably undergoes post-translational modifications. The receptor forms L1, L2 and S bind prolactin with specificity and affinity similar to those reported for the native receptor. They also interact with two monoclonal antibodies, M110 and A917, specific for the native conformation of the hormone-binding site. The I1 and I2 forms do not bind prolactin, whereas the E form does. Thus, the hormone binding site is located in the extracellular domain which can function autonomously as a PRL-binding soluble protein. However, the E form binds prolactin with a higher affinity than the native receptor and it does not bind one of the two antireceptor monoclonal antibodies, known to be hormone binding-site specific. Thus, the conformation of the native receptor and that of the E form differ.     

Prolactin receptors in rat cholangiocytes: Regulation of level and isoform ratio is sex independent

The presence of prolactin receptor and peculiarities of its isoform expression in bile duct cells (cholangiocytes) differentially isolated from rat liver under different conditions were investigated in the present study. Normal cholangiocytes express prolactin receptor at relatively low level comparable to those of some prolactin-dependent tissues. Long receptor isoform is predominant in cholangiocytes but not in hepatocytes. The prolactin receptor level increases significantly under obstructive cholestasis due to evaluation of long and appearance of short isoforms. In rat cholangiocytes, unlike other tissues, the main positive regulators of prolactin receptor expression are cholestasis-induced factors instead of sex hormone and prolactin levels. Long isoform is predominant and induced primarily by cholestasis-induced factors. Published in Russian in Biokhimiya, 2006, Vol. 71, No. 2, pp. 229–236.     

Development of prolactin receptor antagonists with reduced pH‐dependence of receptor binding

The cytokine hormone prolactin has a vast number of diverse functions. Unfortunately, it also exhibits tumor growth promoting properties, which makes the development of prolactin receptor antagonists a priority. Prolactin binds to its cognate receptor with much lower affinity at low pH than at physiological pH and since the extracellular environment around solid tumors often is acidic, it is desirable to develop antagonists that have improved binding affinity at low pH. The pK_a value of a histidine side chain is ～6.8 making histidine residues obvious candidates for examination. From evaluation of known molecular structures of human prolactin, of the prolactin receptor and of different complexes of the two, three histidine residues in the hormone–receptor binding site 1 were selected for mutational studies. We analyzed 10 variants by circular dichroism spectroscopy, affinity and thermodynamic characterization of receptor binding by isothermal titration calorimetry combined with in vitro bioactivity in living cells. Histidine residue 27 was recognized as a central hot spot for pH sensitivity and conservative substitutions at this site resulted in strong receptor binding at low pH. Pure antagonists were developed earlier and the histidine mutations were introduced within such background. The antagonistic properties were maintained and the high affinity at low pH conserved. The implications of these findings may open new areas of research in the field of prolactin cancer biology. Copyright © 2010 John Wiley & Sons, Ltd.     

Remarkable genetic diversity detected at river buffalo prolactin receptor (PRLR) gene and association studies with milk fatty acid composition

Prolactin is an anterior pituitary peptide hormone involved in many different endocrine activities and is essential for reproductive performance. This action is mediated by its receptor, the prolactin receptor, encoded by the PRLR gene. In this study, we sequenced and characterized the Mediterranean river buffalo PRLR gene (from exon 3 to 10), and we found remarkable genetic diversity. In particular, we found 24 intronic polymorphisms and 13 exonic SNPs, seven of which were non‐synonymous. Furthermore, the polymorphisms identified in the 3′‐UTR were investigated to establish their possible influence on microRNA binding sites. Considering all the amino acid changes and the observed allelic combinations, it is possible to deduce at least six different translations of the buffalo prolactin receptor and, consequently, the presence at the PRLR gene of at least six alleles. Furthermore, we identified a deletion of a CACTACC heptamer between nucleotides 1102 and 1103 of exon 10 (3′‐UTR), and we developed an allele‐specific PCR to identify the carriers of this genetic marker. Finally, the SNP g.11188A>G, detected in exon 10 and responsible for the amino acid replacement p.His328Arg, was genotyped in 308 Italian Mediterranean river buffaloes, and an association study with milk fat traits was carried out. The statistical analysis showed a tendency that approached significance for the AA genotype with higher contents of odd branched‐chain fatty acids. Thus, our results suggest that the PRLR gene is a good candidate for gene association studies with qualitative traits related to buffalo milk production.     

Associations between the prolactin receptor gene polymorphism and reproductive traits of boars

The prolactin receptor gene (PRLR), located on chromosome 16 in pigs, is a candidate gene for reproductive traits. The experiment was aimed to detect the DNA mutations in this gene and to find probable relations between the genotype and some reproductive traits in boars. The polymorphism in the PRLR gene was identified by PCR-RFLP method using specific primers and the restriction enzyme AluI. In total 229 boars of various breeds were genotyped. The frequency of allele A was estimated at 0.62 and allele B at 0.38. Genotype AA was found at a frequency of 0.45, AB at 0.35 and BB at 0.20. We found associations between PRLR genotype and ejaculate volume, sperm concentration, percentage of live sperm, and number of live sperm in the ejaculate (P < 0.01).     

Endocrine phenotype,reproductive success and survival in the great tit,Parus major

A central goal in evolutionary ecology is to characterize and identify selection patterns on the optimal phenotype in different environments. Physiological traits, such as hormonal responses, provide important mechanisms by which individuals can adapt to fluctuating environmental conditions. It is therefore expected that selection shapes hormonal traits, but the strength and the direction of selection on plastic hormonal signals are still under investigation. Here, we determined whether, and in which way, selection is acting on the hormones corticosterone and prolactin by characterizing endocrine phenotypes and their relationship with fitness in free‐living great tits, Parus major. We quantified variation in circulating concentrations of baseline and stress‐induced corticosterone and in prolactin during the prebreeding (March) and the breeding season (May) for two consecutive years, and correlated these with reproductive success (yearly fledgling number) and overwinter survival in female and male individuals. In both years, individuals with high baseline corticosterone concentrations in March had the highest yearly fledgling numbers; while in May, individuals with low baseline corticosterone had the highest yearly reproductive success. Likewise, individuals that displayed strong seasonal plasticity in baseline corticosterone concentrations (high in March and low in May) had the highest reproductive success in each year. Prolactin concentrations were not related to reproductive success, but were positively correlated to the proximity to lay. Between‐year plasticity in stress‐induced corticosterone concentrations of males was related to yearly variation in food abundance, but not to overall reproductive success. These findings suggest that seasonally alternating directional selection is operating on baseline corticosterone concentrations in both sexes. The observed between‐year consistency in selection patterns indicates that a one‐time hormone sample in a given season can allow the prediction of individual fitness.