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Our understanding of the basis to immunoglobulin formation in cattle has benefited substantially from the application of molecular biology over the past decade. It is now established that both the lambda light chain and heavy chain repertoires are founded upon the frequent expression of single gene families and subgroups of segments which are of conserved sequence. It is likely that a functional kappa locus exists in the bovine genome but this isotype comprises as few as 5% of bovine light chains. Similarly, alternative but non-expressed V(H) gene families are present posing intriguing but unresolved questions about the regulation of immunoglobulin synthesis. The heavy chain frequently bears a third complementarity-determining region which is atypically long but the processes which expand this region of the reading frame and its contribution to the interaction with antigen remain matters of speculation. Opportunities exist to map the major immunoglobulin loci and to define the membership and sequence diversity of the gene families which dominate each repertoire. However, it is already evident that cattle cannot generate significant diversity from rearrangement and junctional imprecision alone. Elucidation of the mechanism(s), dynamics and tissue distribution of immunoglobulin diversification in cattle, thus, remain key challenges in this branch of veterinary immunology. 相似文献
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ABSTRACT: This review focuses on the diversity of immunoglobulin (Ig) genes and Ig isotypes that are expressed in domestic animals. Four livestock species--cattle, sheep, pigs, and horses--express a full range of Ig heavy chains (IgHs), including mu, delta, gamma, epsilon, and alpha. Two poultry species (chickens and ducks) express three IgH isotypes, mu, upsilon, and alpha, but not delta. The kappa and lambda light chains are both utilized in the four livestock species, but only the lambda chain is expressed in poultry. V(D)J recombination, somatic hypermutation (SHM) and gene conversion (GC) are three distinct mechanisms by which immunoglobulin variable region diversity is generated. Different domestic animals may use distinct means to diversify rearranged variable regions of Ig genes. 相似文献
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Chen L Li M Li Q Yang X An X Chen Y 《Veterinary immunology and immunopathology》2008,124(3-4):284-294
To characterize the bovine immunoglobulin lambda light chain constant region (IGLC) genes, we have isolated a bacterial artificial chromosome (BAC) clone by a PCR based approach from a bovine genomic DNA library, constructed using a genital ridge cell line derived from a male Holstein fetus. The positive BAC clone, containing the bovine IGLC genes, was fully sequenced and had a 138 kb insert. Sequence analysis revealed that the bovine immunoglobulin lambda light chain locus consisted of four joining-constant gene recombination units spanning approximately 20 kb DNA in length. A detailed examination of the recombination signal sequences, RNA splicing sites and coding sequences of the four joining-constant gene recombination units suggested that only two IGLC genes (IGLC2 and IGLC3) were functional while the IGLC1 and IGLC4 appeared to be pseudogenes. This conclusion was further confirmed by a series of RT-PCR amplifications, which also showed that among these four genes the IGLC3 was preferentially expressed in cattle. Phylogenetic analysis indicated that the bovine IGLC genes were more closely related to their equivalents in sheep and goats than that to other mammals. 相似文献
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Weber ER Helps CR Foster AP Perry AC Gruffydd-Jones TJ Hall L Harbour DA Duffus WP 《Veterinary immunology and immunopathology》2000,76(3-4):299-308
A feline splenic cDNA library was screened with a (32)P-labelled cDNA probe encoding the canine IgE epsilon heavy chain subunit. A cDNA sequence of 1614 nucleotides encoding the complete feline IgE heavy chain, as well as a portion of a variable region, was identified. A search of the GenBank database revealed an identity of 82% at the nucleotide level and 76% at the amino acid level between the feline epsilon heavy chain sequence and the canine homologue. In a separate study, feline genomic DNA, isolated from whole feline embryo cells, was subjected to PCR amplification using primers based on known partial genomic DNA sequences for the feline C epsilon gene. Following removal of an intron from the 683 bp PCR product, the coding sequence yielded an ORF of 506 bp. The DNA sequence of this PCR clone differed by a single nucleotide from the cDNA clone. This difference is silent, and therefore the proteins encoded by the two sequences are identical over the regions cloned and sequenced. Phylogenetic analysis of the constant regions of nine immunoglobulin epsilon genes revealed that the feline cDNA is most similar to the canine homologue. 相似文献
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1. Poaching of peacocks, the national bird of India, is illegal. People kill this beautiful pheasant bird for tail feathers and mix the meat with chicken or turkey. Differentiation of the meat of these species is essential in order to address the ambiguity about the origin of the sample. 2. The present study was carried out to investigate the use of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of mitochondrial 12S rRNA gene for identification of these species. 3. Peacock mitochondrial 12S rRNA partial gene was amplified using universal primers, cloned and characterised. It was found to be 446 nucleotides long. 4. Sequence analysis revealed 86.8 and 84.1% similarity with reported turkey and chicken sequences, respectively. Sequence and phylogenetic analysis showed that the peacock is much closer to the turkey than the chicken. 5. PCR-RFLP of 446 bp amplicon using commonly available restriction enzymes AluI and Sau3AI produced a differential pattern for identifying these poultry species unambiguously. 相似文献
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Complementary DNA (cDNA) of prolactin (PRL) and vasoactive intestinal polypeptide (VIP) of the Java sparrow were cloned and sequenced. The proximal region of the PRL promoter was also identified. Java sparrow PRL was found to have 88.3, 88.3, and 89.1% sequence identity at the cDNA level to PRL of chicken, turkey, and duck, respectively. The predicted amino acid sequence had an overall similarity with a comparable region of chicken (91.4%), turkey (88.9%) and duck (92.0%) PRL. Based on the cDNA sequence and genomic structure of the chicken PRL gene, the proximal promoter was characterized. Sequence analysis of the proximal region of Java sparrow PRL promoter revealed a high degree of similarity to that of chicken, turkey and duck PRL promoters. Moreover, cDNA of prepro-VIP was also cloned and sequenced. Java sparrow prepro-VIP shows high similarity to chicken and turkey prepro-VIP. However, the region upstream of the 5' untranslated region of Java sparrow prepro-VIP did not show similarity to that of chicken. These results suggest that the mechanisms, which regulate expression of the VIP gene, may be different between precocial and altricial birds, but expression of the PRL gene may be widely conserved in avian species. 相似文献
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V(D)J recombination, or immunoglobulin gene rearrangement is a developmentally regulated, cell type specific, site directed recombination event that brings either immunoglobulin or T-cell receptor gene segments together to form mature, expressible Ig or TCT genes. This DNA recombination is directed by the recombinational signal sequences or RSS elements present adjacent to Ig and TCR gene segments. The RSS element is composed of a conserved nonamer element and a conserved heptamer element separated by a conserved length spacer region. In this report, we examine the expression of DNA binding proteins that interact with the RSS element in the bovine fetal thymus using EMSA assays. Our data indicates that the nonamer portion of the RSS element is the primary site of recognition for RSS binding proteins expressed in the bovine fetal thymus. We also show that these proteins are expressed from early stages of bovine fetal development through to full term development. 相似文献
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Daly KA Digby M Lefèvre C Mailer S Thomson P Nicholas K Williamson P 《Veterinary immunology and immunopathology》2007,120(3-4):187-200
Marsupial young are born in an under-developed state without mature immune responses. Prior to the maturation of an immune system, marsupial young are heavily reliant upon immune factors secreted in the milk to defend them against potential microbial pathogens in the environment. In this study, we identified and characterized the immunoglobulin heavy chain constant regions, light chains, polymeric Ig receptor (pIgR), J chain, neonatal Fc receptor (alpha chain) (FcRn) and the chemokine CCL28 from the model marsupial species, the tammar wallaby (Macropus eugenii). Low levels of conservation were seen in motifs in C and Cγ associated with receptor binding and or transcytosis, and this may have potential implications for functionality. We evaluated the expression of immunoglobulin genes in the tammar mammary gland throughout lactation and found that two periods of increased expression of immunoglobulin genes occur. These two periods coincide with the birth of the young, and with its first emergence from the pouch. This increased expression may represent a strategy for maternal immunological protection of the pouch young. 相似文献
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功能基因组学研究进展 总被引：3，自引：0，他引：3
2 1世纪是生物时代和信息时代 ,基因组学的研究已从结构基因组学转向功能基因组学 ,对于基因功能的研究也由单一基因转向大规模、批量分析。文章对功能基因组学及相关学科的概念作了概述 ,介绍了功能基因组学的研究内容与研究方法 ,主要包括应用差异显示反转录 PCR、基因表达序列分析 (SAGE)、微点阵、蛋白质组学和生物信息学等研究基因组表达概况、基因组多样性和模式生物学等。 相似文献
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Monoclonal antibodies (Mabs) to bovine immunoglobulin heavy chain of the four major isotypes gamma 1, gamma 2, alpha, mu and the light chains (combined kappa and lambda) were produced and found to cross-react in enzyme-linked immunoassay (ELISA) with immunoglobulins of some other animal species despite the discrete specificity associated with an antibody derived from a single clone. This cross-reactivity, particularly amongst ruminants, could be utilized in serological testing for the diagnosis of disease in these species. For example, Mabs produced against bovine immunoglobulin light chain cross-react with bison immunoglobulin light chain and were used successfully in serological testing as the secondary detection antibody in an indirect ELISA for the diagnosis of Brucella abortus in bison herds in north-western Canada. 相似文献
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野桑蚕肌球蛋白轻链2基因(MLC2)的克隆和序列分析 总被引：2，自引：0，他引：2
利用反转录聚合酶链式反应(RT-PCR)和cDNA末端快速扩增(RACE)技术克隆了野桑蚕间接飞行肌(in-direct flight muscle,IFM)的肌球蛋白轻链2(myosin light chain2,MLC2)基因(GenBank登录号:EU332913),其cDNA序列全长979 bp,包括63 bp的5′端非翻译区序列(5′-UTR)、603 bp的开放读码框(ORF)、终止密码子TAA和310bp的3′端非翻译区序列(3′-UTR)。克隆该基因的内含子序列并分析基因结构表明,该基因包括3个外显子和2个内含子,编码201个氨基酸,预测蛋白质分子质量约22.0 kD,等电点4.67。用在线软件SMART分析显示,野桑蚕MLC2蛋白有2个Ca2+结合基序(EFh)结构域,可以结合Ca2+,属于肌钙蛋白C超家族成员,并且含有保守的可以磷酸化的氨基酸残基,有可能具有磷酸化过程,参与肌动球蛋白ATPase活性的调节。 相似文献
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El-Sayed A Alber J Lämmler C Bönner B Huhn A Kaleta EF Zschöck M 《Journal of veterinary medicine. B, Infectious diseases and veterinary public health》2005,52(1):38-44
The present study was designed to comparatively investigate 19 Staphylococcus aureus strains isolated from specimens of 19 different birds during routine microbiological diagnostics. The S. aureus strains were characterized genotypically by polymerase chain reaction (PCR) amplification using 62 different oligonucleotide primers amplifying genes encoding staphylococcal cell surface proteins, exoproteins and two classes of the accessory gene regulator agr. All 19 investigated S. aureus were positive for the gene segment encoding a S. aureus-specific part of the 23S rRNA, the genes encoding thermostable nuclease (nuc), clumping factor (clfA) and coagulase (coa) and the gene segments encoding the Xr-repetitive region and the immunoglobulin G (IgG)-binding region of protein A (spa). In addition, all tested strains were positive for the genes hla and fnbA and negative for the genes seb, sec, sed, see, sej, tst, eta and etb. The remaining genes, including sbi, hlb, fnbB, ebpS, cna (domains A and B), cap5, cap8, set1, agr class I, agr class II, sea, seg, seh and sei were detected in a variable number of isolates. The presented data give an overview on the distribution of virulence determinants of S. aureus strains isolated from birds. This might be useful to understand the role of these virulence determinants in bird infections. 相似文献