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1.
Sci Rep ; 7(1): 6236, 2017 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-28740209

RESUMO

Genome-wide association studies have identified risk loci for SLE, but a large proportion of the genetic contribution to SLE still remains unexplained. To detect novel risk genes, and to predict an individual's SLE risk we designed a random forest classifier using SNP genotype data generated on the "Immunochip" from 1,160 patients with SLE and 2,711 controls. Using gene importance scores defined by the random forest classifier, we identified 15 potential novel risk genes for SLE. Of them 12 are associated with other autoimmune diseases than SLE, whereas three genes (ZNF804A, CDK1, and MANF) have not previously been associated with autoimmunity. Random forest classification also allowed prediction of patients at risk for lupus nephritis with an area under the curve of 0.94. By allele-specific gene expression analysis we detected cis-regulatory SNPs that affect the expression levels of six of the top 40 genes designed by the random forest analysis, indicating a regulatory role for the identified risk variants. The 40 top genes from the prediction were overrepresented for differential expression in B and T cells according to RNA-sequencing of samples from five healthy donors, with more frequent over-expression in B cells compared to T cells.

2.
Eur Respir J ; 47(3): 898-909, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26585430

RESUMO

In pulmonary sarcoidosis, CD4(+) T-cells expressing T-cell receptor Vα2.3 accumulate in the lungs of HLA-DRB1*03(+) patients. To investigate T-cell receptor-HLA-DRB1*03 interactions underlying recognition of hitherto unknown antigens, we performed detailed analyses of T-cell receptor expression on bronchoalveolar lavage fluid CD4(+) T-cells from sarcoidosis patients.Pulmonary sarcoidosis patients (n=43) underwent bronchoscopy with bronchoalveolar lavage. T-cell receptor α and ß chains of CD4(+) T-cells were analysed by flow cytometry, DNA-sequenced, and three-dimensional molecular models of T-cell receptor-HLA-DRB1*03 complexes generated.Simultaneous expression of Vα2.3 with the Vß22 chain was identified in the lungs of all HLA-DRB1*03(+) patients. Accumulated Vα2.3/Vß22-expressing T-cells were highly clonal, with identical or near-identical Vα2.3 chain sequences and inter-patient similarities in Vß22 chain amino acid distribution. Molecular modelling revealed specific T-cell receptor-HLA-DRB1*03-peptide interactions, with a previously identified, sarcoidosis-associated vimentin peptide, (Vim)429-443 DSLPLVDTHSKRTLL, matching both the HLA peptide-binding cleft and distinct T-cell receptor features perfectly.We demonstrate, for the first time, the accumulation of large clonal populations of specific Vα2.3/Vß22 T-cell receptor-expressing CD4(+) T-cells in the lungs of HLA-DRB1*03(+) sarcoidosis patients. Several distinct contact points between Vα2.3/Vß22 receptors and HLA-DRB1*03 molecules suggest presentation of prototypic vimentin-derived peptides.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Cadeias HLA-DRB1/metabolismo , Receptores de Antígenos de Linfócitos T/imunologia , Sarcoidose Pulmonar/imunologia , Adulto , Líquido da Lavagem Broncoalveolar , Broncoscopia , Feminino , Citometria de Fluxo , Humanos , Pulmão/imunologia , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Suécia
3.
Virology ; 408(1): 64-70, 2010 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-20875907

RESUMO

Phage integrases have the potential of becoming tools for safe site-specific integration of genes into unmodified human genomes. The P2-like phages have been found to have different bacterial host integration sites and consequently they have related integrases with different sequence specificities. In this work the site-specific recombination system of the P2-like phage ΦD145 is characterized. The minimal attB site is determined to 22 nt with 18 nt identity to the core region of attP. A non-coding sequence on the human chromosome 13 is shown to be a rather good substrate for recombination in vivo in bacteria as well as in a plasmid system in HeLa cells when HMG protein recognition sequences are inserted between the left arm-binding site and the core in the complex phage attachment site attP. Thus ΦD145 integrase that belongs to the tyrosine family shows potential as a tool for site-specific integration into the human genome.


Assuntos
Bacteriófagos/enzimologia , Integrases/metabolismo , Recombinação Genética , Sítios de Ligação Microbiológicos , Sequência de Bases , Escherichia coli/genética , Células HeLa , Humanos , Dados de Sequência Molecular , Plasmídeos , Homologia de Sequência
4.
Virology ; 404(2): 240-5, 2010 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-20627350

RESUMO

Temperate coliphage P2 integrates its genome into the host chromosome upon lysogenization via a site-specific recombination event mediated by an integrase belonging to the complex family of tyrosine recombinases. The host integration site attB (BOB') is localized in the end of the cyaR gene and shares 27 nucleotides with the core of attP (COC'). In the present study we determine the minimal attB site using an in vivo recombination assay. Ten nt on the left side (B) are found to be nonessential for recombination. We show that the integrase has higher affinity for the right side (B') compared to B and that artificial B'OB' and an attP site with a matching core (C'OC') are efficient substrates for recombination in vitro. We have analyzed single nucleotides in attB and find that sequence homology within a non-centrally located quadruplet in the hypothetical overlap region is essential for efficient recombination in vivo.


Assuntos
Bacteriófago P2/enzimologia , Bacteriófago P2/genética , Regulação Viral da Expressão Gênica/fisiologia , Integrases/metabolismo , Ligação Proteica , Recombinação Genética , Sítios de Ligação Microbiológicos/genética , Sequência de Bases , Escherichia coli/classificação , Escherichia coli/virologia , Regulação Enzimológica da Expressão Gênica , Integrases/genética , Mutação Puntual , Alinhamento de Sequência
5.
Virology ; 385(2): 303-12, 2009 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-19150106

RESUMO

The Cox protein of the coliphage P2 is multifunctional; it acts as a transcriptional repressor of the Pc promoter, as a transcriptional activator of the P(LL) promoter of satellite phage P4, and as a directionality factor for site-specific recombination. The Cox proteins constitute a unique group of directionality factors since they couple the developmental switch with the integration or excision of the phage genome. In this work, the DNA binding characteristics of the Cox protein of WPhi, a P2-related phage, are compared with those of P2 Cox. P2 Cox has been shown to recognize a 9 bp sequence, repeated at least 6 times in different targets. In contrast to P2 Cox, WPhi Cox binds with a strong affinity to the early control region that contains an imperfect direct repeat of 12 nucleotides. The removal of one of the repeats has drastic effects on the capacity of WPhi to bind to the Pe-Pc region. Again in contrast to P2 Cox, WPhi Cox has a lower affinity to attP compared to the Pe-Pc region, and a repeat of 9 bp can be found that has 5 bp in common with the repeat in the Pe-Pc region. WPhi Cox, however, is essential for excisive recombination in vitro. WPhi Cox, like P2 Cox, binds cooperatively with integrase to attP. Both Cox proteins induce a strong bend in their DNA targets upon binding.


Assuntos
Bacteriófago P2/genética , Bacteriófago P2/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Virais/metabolismo , Integração Viral , Sítios de Ligação Microbiológicos/fisiologia , Bacteriófago P2/imunologia , DNA Viral/genética , DNA Viral/metabolismo , Proteínas de Ligação a DNA/genética , Ligação Proteica , Proteínas Virais/genética
6.
Virology ; 332(1): 284-94, 2005 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-15661160

RESUMO

Bacteriophage P2 integrase (Int) mediates site-specific recombination leading to integration or excision of the phage genome in or out of the bacterial chromosome. Int belongs to the large family of tyrosine recombinases that have two different DNA recognition motifs binding to the arm and core sites, respectively, which are located within the phage attachment sites (attP). In addition to the P2 integrase, the accessory proteins Escherichia coli IHF and P2 Cox are needed for recombination. IHF is a structural protein needed for integration and excision by bending the DNA. As opposed to lambda, only one IHF site is found in P2 attP. P2 Cox controls the direction of recombination by inhibiting integration but being required for excision. In this work, the effects of accessory proteins on the capacity of Int to bind to its DNA recognition sequences are analyzed using electromobility shifts. P2 Int binds with low affinity to the arm site, and this binding is greatly enhanced by IHF. The arm binding domain of Int is located at the N-terminus. P2 Int binds with high affinity to the core site, and this binding is also enhanced by IHF. The fact that the cooperative binding of Int and IHF is strongly reduced by lengthening the distance between the IHF and core binding sites indicates that the distance between these sites may be important for cooperative binding. The Int and Cox proteins also bind cooperatively to attP.


Assuntos
Bacteriófago P2/enzimologia , Proteínas de Ligação a DNA/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/virologia , Integrases/metabolismo , Fatores Hospedeiros de Integração/metabolismo , Proteínas Virais/metabolismo , Bacteriófago P2/genética , Bacteriófago P2/metabolismo , Sítios de Ligação , Escherichia coli/metabolismo , Integração Viral
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