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1.
Pharmacogenomics J ; 22(2): 100-108, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34824386

RESUMO

Indigenous Australians face a disproportionately severe burden of chronic disease relative to other Australians, with elevated rates of morbidity and mortality. While genomics technologies are slowly gaining momentum in personalised treatments for many, a lack of pharmacogenomic research in Indigenous peoples could delay adoption. Appropriately implementing pharmacogenomics in clinical care necessitates an understanding of the frequencies of pharmacologically relevant genetic variants within Indigenous populations. We analysed whole-genome sequence data from 187 individuals from the Tiwi Islands and characterised the pharmacogenomic landscape of this population. Specifically, we compared variant profiles and allelic distributions of previously described pharmacologically significant genes and variants with other population groups. We identified 22 translationally relevant pharmacogenomic variants and 18 clinically actionable guidelines with implications for drug dosing and treatment of conditions including heart disease, diabetes and cancer. We specifically observed increased poor and intermediate metabolizer phenotypes in the CYP2C9 (PM:19%, IM:44%) and CYP2C19 (PM:18%, IM:44%) genes.


Assuntos
Povos Indígenas , Testes Farmacogenômicos , Austrália , Citocromo P-450 CYP2C9/genética , Humanos , Variantes Farmacogenômicos
2.
Environ Microbiol ; 23(7): 3384-3400, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-31943734

RESUMO

The Gypsum Hill (GH) springs on Axel Heiberg Island in the Canadian high Arctic are host to chemolithoautotrophic, sulfur-oxidizing streamers that flourish in the high Arctic winter in water temperatures from -1.3 to 7°C with ~8% salinity in a high Arctic winter environment with air temperatures commonly less than -40°C and an average annual air temperature of -15°C. Metagenome sequencing and binning of streamer samples produced a 96% complete Thiomicrorhabdus sp. metagenome-assembled genome representing a possible new species or subspecies. This is the most cold- and salt-extreme source environment for a Thiomicrorhabdus genome yet described. Metaproteomic and metatranscriptomic analysis attributed nearly all gene expression in the streamers to the Thiomicrorhabdus sp. and suggested that it is active in CO2 fixation and oxidation of sulfide to elemental sulfur. In situ geochemical and isotopic analyses of the fractionation of multiple sulfur isotopes determined the biogeochemical transformation of sulfur from its source in Carboniferous evaporites to biotic processes occurring in the sediment and streamers. These complementary molecular tools provided a functional link between the geochemical substrates and the collective traits and activity that define the microbial community's interactions within a unique polar saline habitat where Thiomicrorhabdus-dominated streamers form and flourish.


Assuntos
Enxofre , Canadá , DNA Bacteriano , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA
3.
Mol Plant Microbe Interact ; 33(6): 842-858, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32116115

RESUMO

The mycoparasite Clonostachys rosea ACM941 is under development as a biocontrol organism against Fusarium graminearum, the causative agent of Fusarium head blight in cereals. To identify molecular factors associated with this interaction, the transcriptomic and exometabolomic profiles of C. rosea and F. graminearum GZ3639 were compared during coculture. Prior to physical contact, the antagonistic activity of C. rosea correlated with a response heavily dominated by upregulation of polyketide synthase gene clusters, consistent with the detected accumulation of corresponding secondary metabolite products. Similarly, prior to contact, trichothecene gene clusters were upregulated in F. graminearum, while those responsible for fusarielin and fusarin biosynthesis were downregulated, correlating with an accumulation of trichothecene products in the interaction zone over time. A concomitant increase in 15-acetyl deoxynivalenol-3-glucoside in the interaction zone was also detected, with C. rosea established as the source of this detoxified mycotoxin. After hyphal contact, C. rosea was found to predominantly transcribe genes encoding cell wall-degradation enzymes, major facilitator superfamily sugar transporters, anion:cation symporters, as well as alternative carbon source utilization pathways, together indicative of a transition to necrotropism at this stage. F. graminearum notably activated the transcription of phosphate starvation pathway signature genes at this time. Overall, a number of signature molecular mechanisms likely contributing to antagonistic activity by C. rosea against F. graminearum, as well as its mycotoxin tolerance, are identified in this report, yielding several new testable hypotheses toward understanding the basis of C. rosea as a biocontrol agent for continued agronomic development and application.


Assuntos
Agentes de Controle Biológico , Fusarium/patogenicidade , Hypocreales/fisiologia , Micotoxinas , Transcriptoma , Metaboloma , Policetídeo Sintases/genética
4.
BMC Genomics ; 20(Suppl 8): 546, 2019 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-31307400

RESUMO

BACKGROUND: Short-read resequencing of genomes produces abundant information of the genetic variation of individuals. Due to their numerous nature, these variants are rarely exhaustively validated. Furthermore, low levels of undetected variant miscalling will have a systematic and disproportionate impact on the interpretation of individual genome sequence information, especially should these also be carried through into in reference databases of genomic variation. RESULTS: We find that sequence variation from short-read sequence data is subject to recurrent-yet-intermittent miscalling that occurs in a sequence intrinsic manner and is very sensitive to sequence read length. The miscalls arise from difficulties aligning short reads to redundant genomic regions, where the rate of sequencing error approaches the sequence diversity between redundant regions. We find the resultant miscalled variants to be sensitive to small sequence variations between genomes, and thereby are often intrinsic to an individual, pedigree, strain or human ethnic group. In human exome sequences, we identify 2-300 recurrent false positive variants per individual, almost all of which are present in public databases of human genomic variation. From the exomes of non-reference strains of inbred mice, we identify 3-5000 recurrent false positive variants per mouse - the number of which increasing with greater distance between an individual mouse strain and the reference C57BL6 mouse genome. We show that recurrently miscalled variants may be reproduced for a given genome from repeated simulation rounds of read resampling, realignment and recalling. As such, it is possible to identify more than two-thirds of false positive variation from only ten rounds of simulation. CONCLUSION: Identification and removal of recurrent false positive variants from specific individual variant sets will improve overall data quality. Variant miscalls arising are highly sequence intrinsic and are often specific to an individual, pedigree or ethnicity. Further, read length is a strong determinant of whether given false variants will be called for any given genome - which has profound significance for cohort studies that pool datasets collected and sequenced at different points in time.


Assuntos
Genômica/métodos , Mutação de Sentido Incorreto/genética , Análise de Sequência de DNA/métodos , Animais , Bases de Dados Genéticas , Etnicidade/genética , Reações Falso-Positivas , Humanos , Camundongos , Projetos de Pesquisa
5.
Mamm Genome ; 29(7-8): 507-522, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29594458

RESUMO

Malaria remains a deadly parasitic disease caused by Plasmodium, claiming almost half a million lives every year. While parasite genetics and biology are often the major targets in many studies, it is becoming more evident that host genetics plays a crucial role in the outcome of the infection. Similarly, Plasmodium infections in mice also rely heavily on the genetic background of the mice, and often correlate with observations in human studies, due to their high genetic homology with humans. As such, murine models of malaria are a useful tool for understanding host responses during Plasmodium infections, as well as dissecting host-parasite interactions through various genetic manipulation techniques. Reverse genetic approach such as quantitative trait loci studies and random mutagenesis screens have been employed to discover novel host genes that affect malaria susceptibility in mouse models, while other targeted studies utilize mouse models to validate observation from human studies. Herein, we review the findings from the past and present studies on murine models of hepatic and erythrocytic stages of malaria and speculate on how the current mouse models benefit from the recent development in CRISPR/Cas9 gene editing technology.


Assuntos
Estudos de Associação Genética , Predisposição Genética para Doença , Interações Hospedeiro-Parasita/genética , Malária/genética , Malária/parasitologia , Plasmodium/fisiologia , Animais , Modelos Animais de Doenças , Eritrócitos/metabolismo , Eritrócitos/parasitologia , Marcação de Genes , Ligação Genética , Estudo de Associação Genômica Ampla , Hepatócitos/metabolismo , Hepatócitos/parasitologia , Humanos , Estágios do Ciclo de Vida , Camundongos , Mutagênese , Locos de Características Quantitativas
6.
Blood ; 128(9): 1290-301, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27465915

RESUMO

The factors that determine red blood cell (RBC) lifespan and the rate of RBC aging have not been fully elucidated. In several genetic conditions, including sickle cell disease, thalassemia, and G6PD deficiency, erythrocyte lifespan is significantly shortened. Many of these diseases are also associated with protection from severe malaria, suggesting a role for accelerated RBC senescence and clearance in malaria resistance. Here, we report a novel, N-ethyl-N-nitrosourea-induced mutation that causes a gain of function in adenosine 5'-monophosphate deaminase (AMPD3). Mice carrying the mutation exhibit rapid RBC turnover, with increased erythropoiesis, dramatically shortened RBC lifespan, and signs of increased RBC senescence/eryptosis, suggesting a key role for AMPD3 in determining RBC half-life. Mice were also found to be resistant to infection with the rodent malaria Plasmodium chabaudi. We propose that resistance to P. chabaudi is mediated by increased RBC turnover and higher rates of erythropoiesis during infection.


Assuntos
AMP Desaminase , Eritrócitos/imunologia , Imunidade Inata , Malária , Mutação , Plasmodium chabaudi/imunologia , AMP Desaminase/genética , AMP Desaminase/imunologia , Animais , Senescência Celular/genética , Senescência Celular/imunologia , Eritrócitos/parasitologia , Eritropoese/genética , Eritropoese/imunologia , Etilnitrosoureia/toxicidade , Meia-Vida , Malária/genética , Malária/imunologia , Masculino , Camundongos
7.
Blood ; 125(3): 534-41, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25414439

RESUMO

Many red cell polymorphisms are a result of selective pressure by the malarial parasite. Here, we add another red cell disease to the panoply of erythrocytic changes that give rise to resistance to malaria. Erythrocytes from individuals with erythropoietic protoporphyria (EPP) have low levels of the final enzyme in the heme biosynthetic pathway, ferrochelatase. Cells from these patients are resistant to the growth of Plasmodium falciparum malarial parasites. This phenomenon is due to the absence of ferrochelatase and not an accumulation of substrate, as demonstrated by the normal growth of P falciparum parasites in the EPP phenocopy, X-linked dominant protoporphyria, which has elevated substrate, and normal ferrochelatase levels. This observation was replicated in a mouse strain with a hypomorphic mutation in the murine ferrochelatase gene. The parasite enzyme is not essential for parasite growth as Plasmodium berghei parasites carrying a complete deletion of the ferrochelatase gene grow normally in erythrocytes, which confirms previous studies. That ferrochelatase is essential to parasite growth was confirmed by showing that inhibition of ferrochelatase using the specific competitive inhibitor, N-methylprotoporphyrin, produced a potent growth inhibition effect against cultures of P falciparum. This raises the possibility of targeting human ferrochelatase in a host-directed antimalarial strategy.


Assuntos
Eritrócitos/parasitologia , Ferroquelatase/fisiologia , Malária Falciparum/prevenção & controle , Plasmodium berghei/crescimento & desenvolvimento , Protoporfiria Eritropoética/prevenção & controle , Animais , Eritrócitos/enzimologia , Feminino , Ferroquelatase/antagonistas & inibidores , Heme/metabolismo , Humanos , Malária Falciparum/enzimologia , Malária Falciparum/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Protoporfiria Eritropoética/enzimologia , Protoporfiria Eritropoética/parasitologia , Protoporfirinas/farmacologia
8.
Infect Immun ; 83(11): 4322-34, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26303393

RESUMO

The treatment of iron deficiency in areas of high malaria transmission is complicated by evidence which suggests that iron deficiency anemia protects against malaria, while iron supplementation increases malaria risk. Iron deficiency anemia results in an array of pathologies, including reduced systemic iron bioavailability and abnormal erythrocyte physiology; however, the mechanisms by which these pathologies influence malaria infection are not well defined. In the present study, the response to malaria infection was examined in a mutant mouse line, Tfrc(MRI24910), identified during an N-ethyl-N-nitrosourea (ENU) screen. This line carries a missense mutation in the gene for transferrin receptor 1 (TFR1). Heterozygous mice exhibited reduced erythrocyte volume and density, a phenotype consistent with dietary iron deficiency anemia. However, unlike the case in dietary deficiency, the erythrocyte half-life, mean corpuscular hemoglobin concentration, and intraerythrocytic ferritin content were unchanged. Systemic iron bioavailability was also unchanged, indicating that this mutation results in erythrocytic iron deficiency without significantly altering overall iron homeostasis. When infected with the rodent malaria parasite Plasmodium chabaudi adami, mice displayed increased parasitemia and succumbed to infection more quickly than their wild-type littermates. Transfusion of fluorescently labeled erythrocytes into malaria parasite-infected mice demonstrated an erythrocyte-autonomous enhanced survival of parasites within mutant erythrocytes. Together, these results indicate that TFR1 deficiency alters erythrocyte physiology in a way that is similar to dietary iron deficiency anemia, albeit to a lesser degree, and that this promotes intraerythrocytic parasite survival and an increased susceptibility to malaria in mice. These findings may have implications for the management of iron deficiency in the context of malaria.


Assuntos
Eritrócitos/metabolismo , Deficiências de Ferro , Malária/parasitologia , Mutação de Sentido Incorreto , Plasmodium chabaudi/fisiologia , Receptores da Transferrina/genética , Animais , Suscetibilidade a Doenças , Feminino , Humanos , Malária/sangue , Masculino , Camundongos , Receptores da Transferrina/metabolismo
9.
BMC Genomics ; 16: 866, 2015 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-26503232

RESUMO

BACKGROUND: N-ethyl-N-nitrosourea (ENU) mutagen has become the method of choice for inducing random mutations for forward genetics applications. However, distinguishing induced mutations from sequencing errors or sporadic mutations is difficult, which has hampered surveys of potential biases in the methodology in the past. Addressing this issue, we created a large cohort of mice with biological replicates enabling the confident calling of induced mutations, which in turn allowed us to conduct a comprehensive analysis of potential biases in mutation properties and genomic location. RESULTS: In the exome sequencing data we observe the known preference of ENU to cause A:T=>G:C transitions in longer genes. Mutations were frequently clustered and inherited in blocks hampering attempts to pinpoint individual causative mutations by genome analysis only. Furthermore, ENU mutations were biased towards areas in the genome that are accessible in testis, potentially limiting the scope of forward genetic approaches to only 1-10% of the genome. CONCLUSION: ENU provides a powerful tool for exploring the genome-phenome relationship, however forward genetic applications that require the mutation to be passed on through the germ line may be limited to explore only genes that are accessible in testis.


Assuntos
Etilnitrosoureia/toxicidade , Mutagênicos/toxicidade , Mutação/genética , Animais , Exoma/efeitos dos fármacos , Exoma/genética , Estudo de Associação Genômica Ampla , Masculino , Camundongos , Mutagênese/efeitos dos fármacos , Mutagênese/genética , Testículo/efeitos dos fármacos , Testículo/metabolismo
10.
Malar J ; 14: 289, 2015 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-26215182

RESUMO

As parasites, Plasmodium species depend upon their host for survival. During the blood stage of their life-cycle parasites invade and reside within erythrocytes, commandeering host proteins and resources towards their own ends, and dramatically transforming the host cell. Parasites aptly avoid immune detection by minimizing the exposure of parasite proteins and removing themselves from circulation through cytoadherence. Erythrocytic disorders brought on by host genetic mutations can interfere with one or more of these processes, thereby providing a measure of protection against malaria to the host. This review summarizes recent findings regarding the mechanistic aspects of this protection, as mediated through the parasites interaction with abnormal erythrocytes. These novel findings include the reliance of the parasite on the host enzyme ferrochelatase, and the discovery of basigin and CD55 as obligate erythrocyte receptors for parasite invasion. The elucidation of these naturally occurring malaria resistance mechanisms is increasing the understanding of the host-parasite interaction, and as discussed below, is providing new insights into the development of therapies to prevent this disease.


Assuntos
Eritrócitos/parasitologia , Predisposição Genética para Doença/genética , Interações Hospedeiro-Parasita/genética , Malária , Plasmodium , Adesão Celular , Eritrócitos/patologia , Hemoglobinopatias/genética , Hemoglobinopatias/parasitologia , Humanos , Malária/genética
11.
Malar J ; 13: 100, 2014 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-24628989

RESUMO

BACKGROUND: Malaria treatments are becoming less effective due to the rapid spread of drug resistant parasites. Increased understanding of the host/parasite interaction is crucial in order to develop treatments that will be less prone to resistance. Parasite invasion of the red blood cell (RBC) is a critical aspect of the parasite life cycle and is, therefore, a promising target for the development of malaria treatments. Assays for analysing parasite invasion in vitro have been developed, but no equivalent assays exist for in vivo studies. This article describes a novel flow cytometric in vivo parasite invasion assay. METHODS: Experiments were conducted with mice infected with erythrocytic stages of Plasmodium chabaudi adami strain DS. Exogenously labelled blood cells were transfused into infected mice at schizogony, and collected blood samples stained and analysed using flow cytometry to specifically detect and measure proportions of labelled RBC containing newly invaded parasites. A combination of antibodies (CD45 and CD71) and fluorescent dyes, Hoechst (DNA) and JC-1 (mitochondrial membrane potential), were used to differentiate parasitized RBCs from uninfected cells, RBCs containing Howell-Jolly bodies, leukocytes and RBC progenitors. Blood cells were treated ex vivo with proteases to examine the effects on in vivo parasite invasion. RESULTS: The staining and flow cytometry analysis method was accurate in determining the parasitaemia down to 0.013% with the limit of detection at 0.007%. Transfused labelled blood supported normal rates of parasite invasion. Protease-treated red cells resulted in 35% decrease in the rate of parasite invasion within 30 minutes of introduction into the bloodstream of infected mice. CONCLUSIONS: The invasion assay presented here is a versatile method for the study of in vivo red cell invasion efficiency of Plasmodium parasites in mice, and allows direct comparison of invasion in red cells derived from two different populations. The method also serves as an accurate alternative method of estimating blood parasitaemia.


Assuntos
Eritrócitos/parasitologia , Citometria de Fluxo/métodos , Malária/veterinária , Parasitologia/métodos , Plasmodium chabaudi/isolamento & purificação , Doenças dos Roedores/parasitologia , Animais , Malária/parasitologia , Camundongos , Camundongos Endogâmicos C57BL
12.
Blood ; 117(4): 1308-10, 2011 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-21115977

RESUMO

We describe a collection of 11 families with ≥ 2 generations of family members whose condition has been diagnosed as a hematologic malignancy. In 9 of these families there was a significant decrease in age at diagnosis in each subsequent generation (anticipation). The mean age at diagnosis in the first generation was 67.8 years, 57.1 years in the second, and 41.8 years in the third (P < .0002). This was confirmed in both direct parent-offspring pairs with a mean reduction of 19 years in the age at diagnosis (P = .0087) and when the analysis was repeated only including cases of mature B-cell neoplasm (P = .0007). We believe that these families provide further insight into the nature of the underlying genetic mechanism of predisposition in these families.


Assuntos
Antecipação Genética/fisiologia , Família , Neoplasias Hematológicas/genética , Adolescente , Adulto , Idade de Início , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Predisposição Genética para Doença , Neoplasias Hematológicas/diagnóstico , Neoplasias Hematológicas/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
13.
Ann Neurol ; 70(6): 897-912, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22190364

RESUMO

OBJECTIVE: To perform a 1-stage meta-analysis of genome-wide association studies (GWAS) of multiple sclerosis (MS) susceptibility and to explore functional consequences of new susceptibility loci. METHODS: We synthesized 7 MS GWAS. Each data set was imputed using HapMap phase II, and a per single nucleotide polymorphism (SNP) meta-analysis was performed across the 7 data sets. We explored RNA expression data using a quantitative trait analysis in peripheral blood mononuclear cells (PBMCs) of 228 subjects with demyelinating disease. RESULTS: We meta-analyzed 2,529,394 unique SNPs in 5,545 cases and 12,153 controls. We identified 3 novel susceptibility alleles: rs170934(T) at 3p24.1 (odds ratio [OR], 1.17; p = 1.6 × 10(-8)) near EOMES, rs2150702(G) in the second intron of MLANA on chromosome 9p24.1 (OR, 1.16; p = 3.3 × 10(-8)), and rs6718520(A) in an intergenic region on chromosome 2p21, with THADA as the nearest flanking gene (OR, 1.17; p = 3.4 × 10(-8)). The 3 new loci do not have a strong cis effect on RNA expression in PBMCs. Ten other susceptibility loci had a suggestive p < 1 × 10(-6) , some of these loci have evidence of association in other inflammatory diseases (ie, IL12B, TAGAP, PLEK, and ZMIZ1). INTERPRETATION: We have performed a meta-analysis of GWAS in MS that more than doubles the size of previous gene discovery efforts and highlights 3 novel MS susceptibility loci. These and additional loci with suggestive evidence of association are excellent candidates for further investigations to refine and validate their role in the genetic architecture of MS.


Assuntos
Suscetibilidade a Doenças , Predisposição Genética para Doença , Esclerose Múltipla/genética , Polimorfismo de Nucleotídeo Único/genética , Adolescente , Adulto , Criança , Feminino , Frequência do Gene , Estudo de Associação Genômica Ampla , Genótipo , Humanos , Masculino , Metanálise como Assunto , Pessoa de Meia-Idade , Esclerose Múltipla/etiologia , Razão de Chances , Adulto Jovem
14.
mSphere ; 7(6): e0045622, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36377914

RESUMO

Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Previous studies on Fusarium species have highlighted the involvement of the Ste2 G-protein-coupled receptor (GPCR) in mediating polarized hyphal growth toward host-released peroxidase. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to Fusarium graminearum chemotropism and pathogenicity. Fgste3Δ deletion strains were found to be compromised in the chemotropic response toward peroxidase, development of lesions on germinating wheat, and infection of Arabidopsis thaliana leaves. In the absence of FgSte3 or FgSte2, F. graminearum cells exposed to peroxidase showed no phosphorylation of the cell-wall integrity, mitogen-activated protein kinase pathway component Mgv1. In addition, transcriptomic gene expression profiling yielded a list of genes involved in cellular reorganization, cell wall remodeling, and infection-mediated responses that were differentially modulated by peroxidase when FgSte3 was present. Deletion of FgSte3 yielded the downregulation of genes associated with mycotoxin biosynthesis and appressorium development, compared to the wild-type strain, both in the presence of peroxidase. Together, these findings contribute to our understanding of the mechanism underlying fungal chemotropism and pathogenesis while raising the novel hypothesis that FgSte2 and FgSte3 are interdependent on each other for the mediation of the redirection of hyphal growth in response to host-derived peroxidase. IMPORTANCE Fusarium head blight of wheat, caused by the filamentous fungus Fusarium graminearum, leads to devastating global food shortages and economic losses. Fungal hyphal chemotropism has been shown to be a major contributor to host-pathogen interactions. Here, the role of the opposite mating type GPCR, Ste3, is characterized with respect to F. graminearum chemotropism and pathogenicity. These findings contribute to our understanding of the mechanisms underlying fungal chemotropism and pathogenesis.


Assuntos
Fusarium , Fusarium/genética , Peroxidases/metabolismo , Proteínas Quinases Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Peroxidase , Receptores Acoplados a Proteínas G/metabolismo
15.
Blood ; 113(14): 3352-62, 2009 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-19179303

RESUMO

Insights into the role of ankyrin-1 (ANK-1) in the formation and stabilization of the red cell cytoskeleton have come from studies on the nb/nb mice, which carry hypomorphic alleles of Ank-1. Here, we revise several paradigms established in the nb/nb mice through analysis of an N-ethyl-N-nitrosourea (ENU)-induced Ank-1-null mouse. Mice homozygous for the Ank-1 mutation are profoundly anemic in utero and most die perinatally, indicating that Ank-1 plays a nonredundant role in erythroid development. The surviving pups exhibit features of severe hereditary spherocytosis (HS), with marked hemolysis, jaundice, compensatory extramedullary erythropoiesis, and tissue iron overload. Red cell membrane analysis reveals a complete loss of ANK-1 protein and a marked reduction in beta-spectrin. As a consequence, the red cells exhibit total disruption of cytoskeletal architecture and severely altered hemorheologic properties. Heterozygous mutant mice, which have wild-type levels of ANK-1 and spectrin in their RBC membranes and normal red cell survival and ultrastructure, exhibit profound resistance to malaria, which is not due to impaired parasite entry into RBC. These findings provide novel insights into the role of Ank-1, and define an ideal model for the study of HS and malarial resistance.


Assuntos
Anquirinas/fisiologia , Células Eritroides/metabolismo , Etilnitrosoureia , Neoplasias Hematológicas/induzido quimicamente , Neoplasias Hematológicas/genética , Animais , Animais Recém-Nascidos , Anquirinas/genética , Anquirinas/metabolismo , Sequência de Bases , Carcinógenos , Citoesqueleto/genética , Citoesqueleto/patologia , Análise Mutacional de DNA , Eritrócitos/efeitos dos fármacos , Eritrócitos/patologia , Eritrócitos Anormais/patologia , Eritropoese/genética , Eritropoese/fisiologia , Neoplasias Hematológicas/patologia , Hemólise/efeitos dos fármacos , Hemólise/genética , Malária/genética , Malária/veterinária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Dados de Sequência Molecular
16.
Antonie Van Leeuwenhoek ; 100(2): 259-77, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21604047

RESUMO

Cold tolerant strains of Acidithiobacillus ferrooxidans play a role in metal leaching and acid mine drainage (AMD) production in northern latitude/boreal mining environments. In this study we used a proteomics and bioinformatics approach to decipher the proteome changes related to sustained growth at low temperatures to increase our understanding of cold adaptation mechanisms in A. ferrooxidans strains. Changes in protein abundance in response to low temperatures (5 and 15°C) were monitored and protein analyses of a psychrotrophic strain (D6) versus a mesophilic strain (F1) showed that both strains increased levels of 11 stress-related and metabolic proteins including survival protein SurA, trigger factor Tig, and AhpC-Tsa antioxidant proteins. However, a unique set of changes in the proteome of psychrotrophic strain D6 were observed. In particular, the importance of protein fate, membrane transport and structure for psychrotrophic growth were evident with increases in numerous chaperone and transport proteins including GroEL, SecB, ABC transporters and a capsule polysaccharide export protein. We also observed that low temperature iron oxidation coincides with a relative increase in the key iron metabolism protein rusticyanin, which was more highly expressed in strain D6 than in strain F1 at colder growth temperatures. We demonstrate that the psychrotrophic strain uses a global stress response and cold-active metabolism which permit growth of A. ferrooxidans in the extreme AMD environment in colder climates.


Assuntos
Acidithiobacillus/fisiologia , Adaptação Fisiológica , Proteínas de Bactérias/metabolismo , Temperatura Baixa , Proteoma/metabolismo , Acidithiobacillus/genética , Acidithiobacillus/crescimento & desenvolvimento , Azurina/metabolismo , Carbono/metabolismo , Biologia Computacional , Eletroforese em Gel Bidimensional , Ferro/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Chaperonas Moleculares/metabolismo , Oxirredução , Estresse Oxidativo , Filogenia , Dobramento de Proteína , Isoformas de Proteínas/metabolismo
17.
J Neurosci ; 29(2): 371-80, 2009 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-19144837

RESUMO

Low-voltage-activated, or T-type, calcium (Ca(2+)) channels are believed to play an essential role in the generation of absence seizures in the idiopathic generalized epilepsies (IGEs). We describe a homozygous, missense, single nucleotide (G to C) mutation in the Ca(v)3.2 T-type Ca(2+) channel gene (Cacna1h) in the genetic absence epilepsy rats from Strasbourg (GAERS) model of IGE. The GAERS Ca(v)3.2 mutation (gcm) produces an arginine to proline (R1584P) substitution in exon 24 of Cacna1h, encoding a portion of the III-IV linker region in Ca(v)3.2. gcm segregates codominantly with the number of seizures and time in seizure activity in progeny of an F1 intercross. We have further identified two major thalamic Cacna1h splice variants, either with or without exon 25. gcm introduced into the splice variants acts "epistatically," requiring the presence of exon 25 to produce significantly faster recovery from channel inactivation and greater charge transference during high-frequency bursts. This gain-of-function mutation, the first reported in the GAERS polygenic animal model, has a novel mechanism of action, being dependent on exonic splicing for its functional consequences to be expressed.


Assuntos
Canais de Cálcio Tipo T/genética , Modelos Animais de Doenças , Epilepsia Tipo Ausência/genética , Mutação Puntual/genética , Isoformas de Proteínas/genética , Convulsões/genética , Animais , Animais Recém-Nascidos , Arginina/genética , Biofísica , Linhagem Celular Transformada , Estimulação Elétrica , Eletroencefalografia , Epilepsia Tipo Ausência/fisiopatologia , Éxons/genética , Humanos , Técnicas In Vitro , Potenciais da Membrana/genética , Potenciais da Membrana/fisiologia , Modelos Moleculares , Mutagênese Sítio-Dirigida/métodos , Técnicas de Patch-Clamp , Prolina/genética , Estrutura Terciária de Proteína/genética , Ratos , Ratos Transgênicos , Convulsões/fisiopatologia , Transfecção
18.
Infect Immun ; 78(6): 2734-44, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20368343

RESUMO

Genetic linkage studies of the host response to Leishmania major, the causative agent of cutaneous leishmaniasis, have identified significant genetic complexity in humans and mice. In the mouse model, multiple loci have been implicated in susceptibility to infection, but to date, the genes underlying these loci have not been identified. We now describe the contribution of a novel candidate gene, Fli1, to both L. major resistance and enhanced wound healing. We have previously mapped the L. major response locus, lmr2, to proximal chromosome 9 in a genetic cross between the resistant C57BL/6 strain and the susceptible BALB/c strain. We now show that the presence of the resistant C57BL/6 lmr2 allele in susceptible BALB/c mice confers an enhanced L. major resistance and wound healing phenotype. Fine mapping of the lmr2 locus permitted the localization of the lmr2 quantitative trait locus to a 5-Mb interval comprising 21 genes, of which microarray analysis was able to identify differential expression in 1 gene-Fli1. Analysis of Fli1 expression in wounded and L. major-infected skin and naïve and infected lymph nodes validated the importance of Fli1 in lesion resolution and wound healing and identified 3 polymorphisms in the Fli1 promoter, among which a GA repeat element may be the important contributor.


Assuntos
Predisposição Genética para Doença , Leishmania major/imunologia , Leishmaniose Cutânea/imunologia , Proteína Proto-Oncogênica c-fli-1/fisiologia , Cicatrização , Animais , Mapeamento Cromossômico , Cruzamentos Genéticos , Feminino , Perfilação da Expressão Gênica , Loci Gênicos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Polimorfismo Genético , Regiões Promotoras Genéticas
19.
Br J Haematol ; 150(4): 456-62, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20560968

RESUMO

A family history of a haematological malignancy (HM) is known to be a risk factor for HMs. However, collections of large families with multiple cases of varied disease types are relatively rare. We describe a collection of 12 families with dense aggregations of multiple HM subtypes. Cases were ascertained from a population based study conducted between 1972 and 1980 in Tasmania, Australia. Diagnoses were confirmed through review and re-examination of stored tissue, pathology reports, Tasmanian Cancer Registry and flow cytometry records. Family trees were generated and kinship coefficients were calculated for all pairs of affected individuals. 120 cases were found in these families. Cases diagnosed with chronic lymphocytic leukaemia (CLL) demonstrated the most significantly increased aggregation (P < 0.0001). There was also significant evidence that those individuals diagnosed at an older age (>53 years), did not aggregate together in families with disease that presented at an earlier age (<20 years) (P = 0.009).


Assuntos
Neoplasias Hematológicas/genética , Síndromes Neoplásicas Hereditárias/genética , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Neoplasias Hematológicas/epidemiologia , Humanos , Lactente , Leucemia Linfocítica Crônica de Células B/epidemiologia , Leucemia Linfocítica Crônica de Células B/genética , Pessoa de Meia-Idade , Síndromes Neoplásicas Hereditárias/epidemiologia , Linhagem , Sistema de Registros , Tasmânia/epidemiologia , Adulto Jovem
20.
Sci Rep ; 10(1): 2303, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-32024943

RESUMO

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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