共查询到20条相似文献,搜索用时 15 毫秒
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Chengshui Liao Mingyuan Liu Xue Bai Pan Liu Xuelin Wang Tingting Li Bin Tang He Gao Qingsong Sun Xidong Liu Ying Zhao Feng Wang Xiuping Wu Pascal Boireau Xiaolei Liu 《PLoS neglected tropical diseases》2014,8(8)
Background
Deoxyribonuclease II (DNase II) is a well-known acidic endonuclease that catalyses the degradation of DNA into oligonucleotides. Only one or a few genes encoding DNase II have been observed in the genomes of many species. 125 DNase II-like protein family genes were predicted in the Trichinella spiralis (T. spiralis) genome; however, none have been confirmed. DNase II is a monomeric nuclease that contains two copies of a variant HKD motif in the N- and C-termini. Of these 125 genes, only plancitoxin-1 (1095 bp, GenBank accession no. ) contains the HKD motif in its C-terminus domain. XM_003370715.1Methodology/Principal Findings
In this study, we cloned and characterised the plancitoxin-1 gene. However, the sequences of plancitoxin-1 cloned from T. spiralis were shorter than the predicted sequences in GenBank. Intriguingly, there were two HKD motifs in the N- and C-termini in the cloned sequences. Therefore, the gene with shorter sequences was named after plancitoxin-1-like (Ts-Pt, 885 bp) and has been deposited in GenBank under accession number . The recombinant protein (rTs-Pt) was expressed in a prokaryotic expression system and purified by nickel affinity chromatography. Western blot analysis showed that rTs-Pt was recognised by serum from T. spiralis-infected mice; the anti-rTs-Pt serum recognised crude antigens but not ES antigens. The Ts-Pt gene was examined at all T. spiralis developmental stages by real-time quantitative PCR. Immunolocalisation analysis showed that Ts-Pt was distributed throughout newborn larvae (NBL), the tegument of adults (Ad) and muscle larvae (ML). As demonstrated by DNase zymography, the expressed proteins displayed cation-independent DNase activity. rTs-Pt had a narrow optimum pH range in slightly acidic conditions (pH 4 and pH 5), and its optimum temperature was 25°C, 30°C, and 37°C. KF984291Conclusions
This study indicated that Ts-Pt was classified as a somatic protein in different T. spiralis developmental stages, and demonstrated for the first time that an expressed DNase II protein from T. spiralis had nuclease activity. 相似文献7.
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Kevin K. A. Tetteh Lindsay B. Stewart Lynette Isabella Ochola Alfred Amambua-Ngwa Alan W. Thomas Kevin Marsh Gareth D. Weedall David J. Conway 《PloS one》2009,4(5)
Background
Endemic human pathogens are subject to strong immune selection, and interrogation of pathogen genome variation for signatures of balancing selection can identify important target antigens. Several major antigen genes in the malaria parasite Plasmodium falciparum have shown such signatures in polymorphism-versus-divergence indices (comparing with the chimpanzee parasite P. reichenowi), and in allele frequency based indices.Methodology/Principal Findings
To compare methods for prospective identification of genes under balancing selection, 26 additional genes known or predicted to encode surface-exposed proteins of the invasive blood stage merozoite were first sequenced from a panel of 14 independent P. falciparum cultured lines and P. reichenowi. Six genes at the positive extremes of one or both of the Hudson-Kreitman-Aguade (HKA) and McDonald-Kreitman (MK) indices were identified. Allele frequency based analysis was then performed on a Gambian P. falciparum population sample for these six genes and three others as controls. Tajima''s D (TjD) index was most highly positive for the msp3/6-like PF10_0348 (TjD = 1.96) as well as the positive control ama1 antigen gene (TjD = 1.22). Across the genes there was a strong correlation between population TjD values and the relative HKA indices (whether derived from the population or the panel of cultured laboratory isolates), but no correlation with the MK indices.Conclusions/Significance
Although few individual parasite genes show significant evidence of balancing selection, analysis of population genomic and comparative sequence data with the HKA and TjD indices should discriminate those that do, and thereby identify likely targets of immunity. 相似文献11.
Roz Laing Taisei Kikuchi Axel Martinelli Isheng J Tsai Robin N Beech Elizabeth Redman Nancy Holroyd David J Bartley Helen Beasley Collette Britton David Curran Eileen Devaney Aude Gilabert Martin Hunt Frank Jackson Stephanie L Johnston Ivan Kryukov Keyu Li Alison A Morrison Adam J Reid Neil Sargison Gary I Saunders James D Wasmuth Adrian Wolstenholme Matthew Berriman John S Gilleard James A Cotton 《Genome biology》2013,14(8):R88
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Carlos Quijano Pavel Tomancak Jesus Lopez-Marti Mikita Suyama Peer Bork Marco Milan David Torrents Miguel Manzanares 《Genome biology》2008,9(12):R176
Background
The physical organization and chromosomal localization of genes within genomes is known to play an important role in their function. Most genes arise by duplication and move along the genome by random shuffling of DNA segments. Higher order structuring of the genome occurs in eukaryotes, where groups of physically linked genes are co-expressed. However, the contribution of gene duplication to gene order has not been analyzed in detail, as it is believed that co-expression due to recent duplicates would obscure other domains of co-expression.Results
We have catalogued ordered duplicated genes in Drosophila melanogaster, and found that one in five of all genes is organized as tandem arrays. Furthermore, among arrays that have been spatially conserved over longer periods than would be expected on the basis of random shuffling, a disproportionate number contain genes encoding developmental regulators. Using in situ gene expression data for more than half of the Drosophila genome, we find that genes in these conserved clusters are co-expressed to a much higher extent than other duplicated genes.Conclusions
These results reveal the existence of functional constraints in insects that retain copies of genes encoding developmental and regulatory proteins as neighbors, allowing their co-expression. This co-expression may be the result of shared cis-regulatory elements or a shared need for a specific chromatin structure. Our results highlight the association between genome architecture and the gene regulatory networks involved in the construction of the body plan. 相似文献17.
Background
Whole genome studies have highlighted duplicated genes as important substrates for adaptive evolution. We have investigated adaptive evolution in this class of genes in the human parasite Trypanosoma brucei, as indicated by the ratio of non-synonymous (amino-acid changing) to synonymous (amino acid retaining) nucleotide substitution rates.Methodology/Principal Findings
We have identified duplicated genes that are most rapidly evolving in this important human parasite. This is the first attempt to investigate adaptive evolution in this species at the codon level. We identify 109 genes within 23 clusters of paralogous gene expansions to be subject to positive selection.Conclusions/Significance
Genes identified include surface antigens in both the mammalian and insect host life cycle stage suggesting that competitive interaction is not solely with the adaptive immune system of the mammalian host. Also surface transporters related to drug resistance and genes related to developmental progression are detected. We discuss how adaptive evolution of these genes may highlight lineage specific processes essential for parasite survival. We also discuss the implications of adaptive evolution of these targets for parasite biology and control. 相似文献18.
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Differential DNA methylation in discrete developmental stages of the parasitic nematode Trichinella spiralis 总被引:1,自引:0,他引:1
Fei Gao Xiaolei Liu Xiu-Ping Wu Xue-Lin Wang Desheng Gong Hanlin Lu Yudong Xia Yanxia Song Junwen Wang Jing Du Siyang Liu Xu Han Yizhi Tang Huanming Yang Qi Jin Xiuqing Zhang Mingyuan Liu 《Genome biology》2012,13(10):1-13