Bovine β-defensin gene family: opportunities to improve animal health? (original) (raw)
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Evolution, expression and effectiveness in a cluster of novel bovine β-defensins
Immunogenetics, 2008
The anti-microbial peptides β-defensins constitute a large family of innate immune effector molecules, conserved across a wide species range. In this paper, we describe a systematic search of the sequenced bovine genome to characterise this extensive gene family in Bos taurus, providing an insight into the pattern of conservation of β-defensin genes between species. We have sequenced a sub-set of these newly discovered bovine β-defensin genes and also report expression data for these genes across a range of tissues. We have synthesised the peptide product of one of these genes, bovine β-defensin 123, and found it to be a potent inhibitor of several pathogenic microbes, particularly Escherichia coli and Listeria monocytogenes.
Genome-level identification, gene expression, and comparative analysis of porcine β-defensin genes
BMC Genetics, 2012
Background Beta-defensins (β-defensins) are innate immune peptides with evolutionary conservation across a wide range of species and has been suggested to play important roles in innate immune reactions against pathogens. However, the complete β-defensin repertoire in the pig has not been fully addressed. Result A BLAST analysis was performed against the available pig genomic sequence in the NCBI database to identify β-defensin-related sequences using previously reported β-defensin sequences of pigs, humans, and cattle. The porcine β-defensin gene clusters were mapped to chromosomes 7, 14, 15 and 17. The gene expression analysis of 17 newly annotated porcine β-defensin genes across 15 tissues using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) showed differences in their tissue distribution, with the kidney and testis having the largest pBD expression repertoire. We also analyzed single nucleotide polymorphisms (SNPs) in the mature peptide region of pBD ...
Proteins, 2008
Host defense peptides (historically called antimicrobial peptides, AMPs) are key components in the mammalian innate immune system, and are responsible for both direct killing and immunomodulatory effects in host defense against pathogenic organisms. In order to identify novel host defense peptides by sequence analysis, we constructed the AMPer resource (http://www.cnbi2.com/cgi-bin/amp.pl) that utilizes hidden Markov models to recognize sequences of antimicrobial peptides. In the current work, we utilized the AMPer resource to search bovine expressed sequence tags from the NCBI dbEST project and the bovine genome sequence for novel host defense peptides. Of the 34 known bovine AMPs, 27 were identified with high confidence in the AMPs predicted from ESTs. A further potential 68 AMPs predicted from the EST data were found that appear to be novel giving a total estimate of 102 AMPs present in the genome. Two of these were cathelicidins and selected for experimental verification in RNA ...
Expression and polymorphism of defensins in farm animals
Acta biochimica Polonica, 2010
Due to their activity against bacteria, viruses, and fungi, antimicrobial peptides are important factors in the innate resistance system of humans and animals. They are called "new generation antibiotics" for their potential use in preventive and therapeutic medicine. The most numerous group of antimicrobial peptides is a family of cationic peptides which include defensins and cathelicidins. Among them the most common are peptides with a beta-sheet structure containing three intra-molecular disulphide bonds, called defensins, comprising three classes: alpha, beta, and theta. The class of beta-defensins is the largest one. Their transcripts have been found in many tissues of humans and animals. The aim of this paper is to present the current knowledge about antimicrobial peptides from the defensin family in farm animals, their expression, polymorphism, as well as the potential of their use as genetic markers of health and production traits.
Primate β-defensins - Structure, Function and Evolution
Current Protein & Peptide Science, 2005
Host defense peptides (HDPs) are endogenous antibiotics that play a multifunctional role in the innate immunity of mammals. Among these, β-defensins contribute to mucosal and epithelial defense, also acting as signal molecules for cellular components of innate and adaptive immunity. Numerous members of this family have been identified in mammalian and avian species, and genomic studies in human and mouse indicate a considerable complexity in their gene organization. Recent reports on the evolution of primate and rodent members of this family indicate quite a complex pattern of variation. In this review we briefly discuss the evolution of mammalian β-defensins in relation to other types of defensins, and then concentrate on the evolution of β-defensins 1 to 4 in primates. In particular, the surprisingly varied patterns of evolution, which range from neutral or weakly purifying, to positive selection to a high level of conservation are analyzed in terms of possible genetics, structural or functional implications, as well as to observed variations on the antimicrobial activity in vitro. The role of polymorphisms in the genes encoding for these host defense peptides in determining susceptibility to human diseases are also briefly considered.
Molecular Evolutionary Analysis of a-Defensin Peptides in Vertebrates
Rajshahi University Journal of Science and Engineering, 2016
α-Defensin is a group of polypeptides with antimicrobial activity found in the host defense system and it is widely distributed in, but not limited to mammalian epithelial cells and phagocytes. These molecules protect the organism from a diverse spectrum of bacteria, viruses, fungi, and protozoan parasites. Different studies have revealed widesequence variation within α-defensin sequences, but the underlying evolutionary cause is not well-studied. In this study, the α-defensin gene from 25 vertebrate species has been comprehensively collected and computationally analyzed. NCBI gene and nucleotide databases were accessed to extract meta-information about α-defensin gene's defensin domain and leader propeptide sequences. Full coding sequences downloaded from nucleotide database by splitting out intron sequence. MEGA software used to construct phylogenetic tree using Neighbor-Joining method, which indicates that α-defensin gene evolution does not matches with species evolution. Sel...
Bioinformatic and expression analysis of novel porcine β-defensins
Mammalian Genome, 2006
b-Defensins are a major group of mammalian antimicrobial peptides. Although more than 30 b-defensins have been identified in humans, only one porcine b-defensin has been reported. In this article we report the identification and initial characterization of 11 novel porcine b-defensins (pBD). Using bioinformatic approaches, we screened 287,821 porcine expressed sequence tags for similarity of their predicted peptides to known human b-defensins and identified full-length or partial sequences for the 11 novel pBDs. Similar to the previously identified pBD1, all of these peptides have a consensus b-defensin motif. A differential expression pattern for these newly identified genes was found. For example, unlike most b-defensins, pBD2 and pBD3 were expressed in bone marrow and in other lymphoid tissues including thymus, spleen, lymph nodes, duodenum, and liver. Including pBD2 and pBD3, six porcine b-defensins were expressed in lung and skin. Several newly identified porcine b-defensins, including pBD123, pBD125, and pBD129, were expressed in male reproductive tissues, including lobuli testis and some segments of the epididymis. Phylogenetic analysis indicates that in most cases the evolutionary relationship between individual porcine b-defensins and their human orthologs is closer than the relationship among b-defensins in the same species. These findings establish the existence of multiple porcine b-defensins and suggest that the pig may be an ideal model for the characterization of b-defensin diversity and function.
β-Defensin Antibiotic Peptides in the Innate Immunity of the Buffalo: In Vivo and In Vitro Studies
Alternatives to Laboratory Animals
β-Defensin antimicrobial peptides are multifunctional biomolecules, which are a major component of the oxygen-independent microbicidal system of buffalo polymorphonuclear (PMN) cells. They have great potential for use as proteomic biomarkers of host cell responses in the presence of microbial agents. On purifying these peptides by RP-HPLC, four defensin peptides were revealed. The results from testing against Escherichia coli, Staphylococcus aureus, Streptococcus pyogenes, Candida albicans, Rinderpest Virus (RPV) and Newcastle Disease Virus (NDV), showed that the peptides possessed antimicrobial and antiviral activities. Minimum inhibitory concentration (MIC) values varied according to the peptide amounts and the exposure time. Furthermore, an increase in the levels of these cationic antimicrobial peptides was apparent in milk obtained from natural cases of mastitis, as compared to the levels in normal milk. MALDI-TOF-based amino acid sequencing confirmed the expression of two β-defensins (LAP and BNBD-2) in mastitis milk. A comparison of peptide sequences revealed that buffalo LAP and BNBD-2 share 98.6% and 100% sequence identity, respectively, with those of cattle. In vitro, Bovine Viral Diarrhoea Virus (BVDV) infection was shown to induce the expression of the β-defensin gene, as evidenced by the PCR amplification of cDNA with specific primers. The determination of the enhanced expression of β-defensin peptides in mastitis milk and in PMN cells, can be considered as an advanced approach to the assessment of cellular and molecular responses to cell injury. It is hoped that in vitro studies on phagocytes such as PMN cells and other cell lines, will eventually replace the use of animals in elucidating the roles of these cytokines in response to microbe-derived cell damage. It will also be possible to use defensins as biomarkers to correlate failure in host cell defence systems with peptide heterogeneity.
Molecular cloning and tissue expression of porcine β-defensin-1
FEBS Letters, 1998
Beta-defensins constitute an emerging family of cysteine-rich antimicrobial peptides, which are particularly prominent at mucosal epithelial sites in mammals. Here we report the identification of a novel L L-defensin from porcine tissues, porcine L L-defensin-1 (pBD-1). The cDNA sequence of pBD-1 encoded a 64 amino acid prepro-peptide, which contained the L L-defensin consensus sequence of six invariantly spaced cysteine residues. Northern blot analysis showed that pBD-1 was expressed abundantly in tongue epithelia and that the expression was regulated developmentally. Using RT-PCR, pBD-1 mRNA was detected throughout the respiratory and digestive tracts and also in thymus, spleen, lymph node, brain, liver, kidney, urinary bladder, testis, skin, heart, muscle, bone marrow, peripheral blood neutrophils, alveolar macrophages, and umbilical cord. The wide expression of pBD-1 suggests that this endogenous peptide antibiotic may contribute to both mucosal and systemic host defenses in pigs, which may have implications for the use of porcine tissues and organs in xenotransplantation.
Primate beta-defensins--structure, function and evolution
Current protein & peptide science, 2005
Host defense peptides (HDPs) are endogenous antibiotics that play a multifunctional role in the innate immunity of mammals. Among these, beta-defensins contribute to mucosal and epithelial defense, also acting as signal molecules for cellular components of innate and adaptive immunity. Numerous members of this family have been identified in mammalian and avian species, and genomic studies in human and mouse indicate a considerable complexity in their gene organization. Recent reports on the evolution of primate and rodent members of this family indicate quite a complex pattern of variation. In this review we briefly discuss the evolution of mammalian beta-defensins in relation to other types of defensins, and then concentrate on the evolution of beta-defensins 1 to 4 in primates. In particular, the surprisingly varied patterns of evolution, which range from neutral or weakly purifying, to positive selection to a high level of conservation are analyzed in terms of possible genetics, ...