RESUMO
Chikungunya virus (CHIKV) is a rapidly spreading re-emergent virus transmitted from mosquitoes to humans. The emergence of epidemic variants has been associated with changes in the viral genome, such as the duplication of repeated sequences in the 3' untranslated region (UTR). Indeed, blocks of repeated sequences seemingly favor RNA recombination, providing the virus with a unique ability to continuously change the 3'UTR architecture during host switching. In this work, we provide experimental data on the molecular mechanism of RNA recombination and describe specific sequence and structural elements in the viral 3'UTR that favor template switching of the viral RNA-dependent RNA polymerase on the 3'UTR. Furthermore, we found that a 3'UTR deletion mutant that exhibits markedly delayed replication in mosquito cells and impaired transmission in vivo, recombines in reference laboratory strains of mosquitoes. Altogether, our data provide novel experimental evidence indicating that RNA recombination can act as a nucleic acid repair mechanism to add repeated sequences that are associated to high viral fitness in mosquito during chikungunya virus replication.
Assuntos
Regiões 3' não Traduzidas , Vírus Chikungunya , Genoma Viral , RNA Viral , Recombinação Genética , Replicação Viral , Vírus Chikungunya/genética , Regiões 3' não Traduzidas/genética , RNA Viral/genética , RNA Viral/metabolismo , Animais , Replicação Viral/genética , Febre de Chikungunya/virologia , Febre de Chikungunya/genética , Febre de Chikungunya/transmissão , Humanos , Aedes/virologia , Aedes/genética , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo , Linhagem CelularRESUMO
Research has identified the large conductance voltage- and calcium-activated potassium channel (BK) as a key regulator of neuronal excitability genetically associated to behavioral alcohol tolerance. Sensitivity to ethanol at the molecular level is characterized by acute potentiation of channel activity. BK isoforms show variations in alcohol sensitivity and are differentially distributed on the plasma membrane surface in response to prolonged exposure. MicroRNA (MiRNA) targeting of alcohol-sensitive isoforms coupled with active internalization of BK channels in response to ethanol are believed to be key in establishing homeostatic adaptations that produce persistent changes within the plasma membrane of neurons. In fact, microRNA 9 (miR-9) upregulated expression is a key event in persistent alcohol tolerance mediating acute EtOH desensitization of BK channels. The exact nature of these interactions remains a current topic of discussion. To further study the effects of miR-9 on the expression and distribution of BK channel isoforms we designed an experimental model by transfecting human BK channel isoforms ZERO heterologous constructs in human embryonic kidney cells 293 (HEK293) cells respectively expressing 2.1 (miR-9 responsive), 2.2 (unresponsive) and control (no sequence) 3'untranslated region (3'UTR) miRNA recognition sites. We used imaging techniques to characterize the stably transfected monoclonal cell lines, and electrophysiology to validate channel activity. Finally, we used immunocytochemistry to validate isoform responsiveness to miR-9. Our findings suggest the cell lines were successfully transfected to express either the 2.1 or 2.2 version of ZERO. Patch clamp recordings confirm that these channels retain their functionality and immunohistochemistry shows differential responses to miR-9, making these cells viable for use in future alcohol dependence studies.
Assuntos
Canais de Potássio Ativados por Cálcio de Condutância Alta , MicroRNAs , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Alta/genética , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Regiões 3' não Traduzidas/genética , Células HEK293 , Etanol/farmacologia , MicroRNAs/genética , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Rim/metabolismo , Cálcio/metabolismoRESUMO
Hepatitis C virus (HCV) infection is a major cause of chronic liver disease. Chronic HCV infection is also an important cause of hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). HCV has the capacity to evade immune surveillance by altering the host immune response. Moreover, variations in immune-related genes can lead to differential susceptibility to HCV infection as well as interfere on the susceptibility to the development of hepatic fibrosis, cirrhosis and HCC. The human leucocyte antigen G (HLA-G) gene codes for an immunomodulatory protein known to be expressed in the maternal-foetal interface and in immune-privileged tissues. The HLA-G 3' untranslated region (3'UTR) is important for mRNA stability, and variants in this region are known to impact gene expression. Studies, mainly focusing in a 14 bp insertion/deletion polymorphism, have correlated HLA-G 3'UTR with susceptibility to viral infections, but other polymorphic variants in the HLA-G 3'UTR might also affect HCV infection as they are inherited as haplotypes. The present study evaluated HLA-G 3'UTR polymorphisms and performed linkage disequilibrium test and haplotype assembly in 286 HCV infected patients who have developed fibrosis, cirrhosis or HCC, as well as in 129 healthy control subjects. Haplotypes UTR-1, UTR-2 and UTR-3 were the most observed in HCV+ patients, in the frequencies of 0.276, 0.255 and 0.121, respectively. No statistically significant difference was observed between HCV+ and control subjects, even when patients were grouped according to outcome (HCC, cirrhosis or fibrosis). Despite that, some trends in the results were observed, and therefore, we cannot rule out the possibility that variants associated to high HLA-G expression can be involved in HCV infection susceptibility.
Assuntos
Carcinoma Hepatocelular , Hepatite C , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/genética , Regiões 3' não Traduzidas/genética , Hepacivirus , Antígenos HLA-G/genética , Haplótipos/genética , Neoplasias Hepáticas/genética , Cirrose Hepática/genética , Hepatite C/complicações , Hepatite C/genéticaRESUMO
BACKGROUND: Familial hypercholesterolemia (FH) is caused by pathogenic variants in low-density lipoprotein (LDL) receptor (LDLR) or its associated genes, including apolipoprotein B (APOB), proprotein convertase subtilisin/kexin type 9 (PCSK9), and LDLR adaptor protein 1 (LDLRAP1). However, approximately 40% of the FH patients clinically diagnosed (based on FH phenotypes) may not carry a causal variant in a FH-related gene. Variants located at 3' untranslated region (UTR) of FH-related genes could elucidate mechanisms involved in FH pathogenesis. This study used a computational approach to assess the effects of 3'UTR variants in FH-related genes on miRNAs molecular interactions and to explore the association of these variants with molecular diagnosis of FH. METHODS AND RESULTS: Exons and regulatory regions of FH-related genes were sequenced in 83 FH patients using an exon-target gene sequencing strategy. In silico prediction tools were used to study the effects of 3´UTR variants on interactions between miRNAs and target mRNAs. Pathogenic variants in FH-related genes (molecular diagnosis) were detected in 44.6% FH patients. Among 59 3'UTR variants identified, LDLR rs5742911 and PCSK9 rs17111557 were associated with molecular diagnosis of FH, whereas LDLR rs7258146 and rs7254521 and LDLRAP1 rs397860393 had an opposite effect (p < 0.05). 3´UTR variants in LDLR (rs5742911, rs7258146, rs7254521) and PCSK9 (rs17111557) disrupt interactions with several miRNAs, and more stable bindings were found with LDLR (miR-4435, miR-509-3 and miR-502) and PCSK9 (miR-4796). CONCLUSION: LDLR and PCSK9 3´UTR variants disturb miRNA:mRNA interactions that could affect gene expression and are potentially associated with molecular diagnosis of FH.
Assuntos
Hiperlipoproteinemia Tipo II , MicroRNAs , Humanos , Pró-Proteína Convertase 9/genética , Regiões 3' não Traduzidas/genética , MicroRNAs/genética , Hiperlipoproteinemia Tipo II/genética , Hiperlipoproteinemia Tipo II/diagnóstico , Receptores de LDL/genética , MutaçãoRESUMO
The spread of Zika virus (ZIKV) from the African continent to the Americas promoted its molecular evolution, as reflected by mutations in its RNA genome. Most of the ZIKV genome sequences in the GenBank database have incomplete 5' and 3' UTR sequences, reflecting the deficiency of whole-genome sequencing technologies to resolve the sequences of the genome ends. We modified a protocol for rapid amplification of cDNA ends (RACE) to determine the complete sequences of the 5' and 3' UTRs of a previously reported ZIKV isolate (GenBank no. MH544701.1). This strategy is useful for determining 5' and 3' UTR sequences of ZIKV isolates and will be useful for comparative genomics applications.
Assuntos
Infecção por Zika virus , Zika virus , Humanos , Zika virus/genética , Regiões 3' não Traduzidas/genética , RNA Viral/genética , Evolução Molecular , Regiões 5' não Traduzidas/genética , Genoma Viral/genéticaRESUMO
NRAMP1 and VDR gene polymorphisms have been variably associated with susceptibility to tuberculosis (TB) amongst populations having different genetic background. NRAMP1 and VDR gene variants' association with susceptibility to active infection by Mycobacterium tuberculosis (Mtb) was analyzed in the Warao Amerindian population, an ethnic population from Venezuela's Orinoco delta region. Genomic DNA was extracted from individuals with and without TB to evaluate genetic polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Four NRAMP1 gene polymorphisms were analyzed: D543N (rs17235409), 3' UTR (rs17235416), INT4 (rs3731865), and 274C/T (rs2276631), and one VDR gene polymorphism: FokI (rs2228570). The results showed that the genotypes D543N-A/A, 3'UTR-TGTG+/+, INT4-C/C, and 274C/T-T/T of known polymorphism in the NRAMP1 gene, as well as the genotypes FokI-F/f and FokI-f/f in the VDR gene were most often found in indigenous Warao with active TB. Binomial logistic regression was used for evaluating associations between polymorphisms and risk of contracting TB, an association between NRAMP1-D543N-A/A genotype distribution and TB susceptibility was found in Warao Amerindians. Regarding Venezuelan populations having different genetic backgrounds; statistically significant TB associations concerning NRAMP1-D543N-A/A, INT4-C/C and 3'UTR-TGTG+/+ variant genotype distributions in Warao Amerindians (indigenous) compared to Creole (admixed non-indigenous population) individuals were found. In conclusion, the results thus indicated that the association between NRAMP1-D543N-A/A genotype and TB in Warao Amerindians could support such allele's role in host susceptibility to Mtb infection.
Assuntos
Proteínas de Transporte de Cátions , Tuberculose , Humanos , Regiões 3' não Traduzidas/genética , Venezuela , Predisposição Genética para Doença , Proteínas de Transporte de Cátions/genética , Tuberculose/genética , Genótipo , Estudos de Casos e ControlesRESUMO
RNA viral genomes compact information into functional RNA structures. Here, using chikungunya virus as a model, we investigated the structural requirements of conserved RNA elements in the 3' untranslated region (3'UTR) for viral replication in mosquito and mammalian cells. Using structural predictions and co-variation analysis, we identified a highly stable and conserved Y-shaped structure (SLY) at the end of the 3'UTR that is duplicated in the Asian lineage. Functional studies with mutant viruses showed that the SLY has host-specific functions during viral replication and evolution. The SLY positively modulates viral replication in mosquito cells but has the opposite effect in mammalian cells. Additional structural/functional analyses showed that maintaining the Y-shaped fold and specific nucleotides in the loop are critical for full SLY functionality and optimal viral replication in mosquito cells. Experimental adaptation of viruses with duplicated SLYs to mammalian cells resulted in the generation of heterogeneous viral populations comprising variants with diverse 3'UTRs, contrasting with the homogeneous populations from viruses without SLY copies. Altogether, our findings constitute the first evidence of an RNA secondary structure in the 3'UTR of chikungunya virus genome that plays host-dependent functions.
Assuntos
Vírus Chikungunya , Culicidae , Animais , Regiões 3' não Traduzidas/genética , Vírus Chikungunya/genética , RNA Viral/genética , RNA Viral/química , Culicidae/genética , Replicação Viral/genética , Genoma Viral , MamíferosRESUMO
The 3' untranslated region has an important role in gene regulation through microRNAs, and it has been estimated that microRNAs regulate up to 50% of coding genes in mammals. With the aim of allelic variant identification of 3' untranslated region microRNA seed sites, the 3' untranslated region was searched for seed sites of four temperament-associated genes (CACNG4, EXOC4, NRXN3, and SLC9A4). The microRNA seed sites were predicted in the four genes, and the CACNG4 gene had the greatest number with 12 predictions. To search for variants affecting the predicted microRNA seed sites, the four 3' untranslated regions were re-sequenced in a Brahman cattle population. Eleven single nucleotide polymorphisms were identified in the CACNG4, and eleven in the SLC9A4. Rs522648682:T>G of the CACNG4 gene was located at the predicted seed site for bta-miR-191. Rs522648682:T>G evidenced an association with both exit velocity (p = 0.0054) and temperament score (p = 0.0097). The genotype TT had a lower mean exit velocity (2.93 ± 0.4 m/s) compared with the TG and GG genotypes (3.91 ± 0.46 m/s and 3.67 ± 0.46 m/s, respectively). The allele associated with the temperamental phenotype antagonizes the seed site, disrupting the bta-miR-191 recognition. The G allele of CACNG4-rs522648682 has the potential to influence bovine temperament through a mechanism associated with unspecific recognition of bta-miR-191.
Assuntos
MicroRNAs , Bovinos/genética , Animais , MicroRNAs/genética , Regiões 3' não Traduzidas/genética , Temperamento , Genótipo , Fenótipo , Mamíferos/genéticaRESUMO
The physiological expression of HLA-G is mainly observed in the placenta, playing an essential role in maternal-fetal tolerance. Among the HLA-G mRNA alternative transcripts, the one lacking 92 bases at the HLA-G 3' untranslated region (3'UTR), the 92bDel transcript, is more stable, is associated with increased HLA-G soluble levels, and was observed in individuals presenting a 14 bp insertion (14 bp+) at the 3'UTR. We investigated the presence of the 92bDel transcript in placenta samples, correlating its expression levels with the HLA-G polymorphisms at the 3'UTR. The 14 bp+ allele correlates with the presence of the 92bDel transcript. However, the polymorphism triggering this alternative splicing is the + 3010/C allele (rs1710, allele C). Most 14 bp+ haplotypes (UTR-2/-5/-7) present allele + 3010/C. However, 14 bp- haplotypes such as UTR-3 are also associated with + 3010/C, and the 92bDel transcript can be detected in homozygous samples for the 14 bp- allele carrying at least one copy of UTR-3. The UTR-3 haplotype is associated with alleles G*01:04 and the HLA-G lineage HG0104, which is a high-expressing lineage. The only HLA-G lineage that is not likely to produce this transcript is HG010101, associated with the + 3010/G allele. This functional difference may be advantageous, considering the high worldwide frequency of the HG010101 lineage. Therefore, HLA-G lineages are functionally distinct regarding the 92bDel transcript expression, and the 3010/C allele triggers the alternative splicing that produces this shorter and more stable transcript.
Assuntos
Antígenos HLA-G , Polimorfismo de Nucleotídeo Único , Gravidez , Feminino , Humanos , Antígenos HLA-G/genética , Regiões 3' não Traduzidas/genética , Genótipo , Nucleotídeos , Haplótipos/genética , Frequência do GeneRESUMO
MicroRNAs (miRs) are small non-coding RNAs of 21-24 nucleotides in length that modulate gene expression by targeting the untranslated region (UTR) of mRNA. Single-nucleotide variants (SNVs) in primary miRs (pri-miRs), precursor miRs (pre-miRs), promoters of pri-miRs, and seed regions can affect miR stability or processing, may influence mature miR expression, and can affect target gene identification, respectively. The present protocol tests the binding and activity of miRs on 3'-UTR target sequences based on the expression of luciferase as a reporter gene fused to the UTR sequence in the presence of plasmids containing pre-miR of interest to test in vitro cell culture assay.
Assuntos
MicroRNAs , MicroRNAs/genética , Genes Reporter , Bioensaio , Técnicas de Cultura de Células , Regiões 3' não Traduzidas/genética , NucleotídeosRESUMO
Human Leukocyte Antigen (HLA)-G participates in several biological processes, including reproduction, vascular remodeling, immune tolerance, and hypoxia response. HLA-G is a potential candidate gene for high altitude adaptation since its expression is modulated in both micro and macro environment under hypoxia and constant cellular stress. Besides the promoter region, the HLA-G 3'untranslated region (UTR) influences HLA-G expression patterns through several post-transcriptional mechanisms. Currently, the 3'UTR genetic diversity in terms of altitude adaptation of Native American populations is still unexplored, particularly at high altitude ecoregions. Here, we evaluated 288 Native Americans from 9 communities located in the Andes [highland (HL); ≥2,500 m (range = 2,838-4,433 m)] and 8 populations located in lowland (LL) regions [<2,500 m (range = 80-431 m); Amazonian tropical forest, Brazilian central plateau, and Chaco] of South America. In total, nine polymorphic sites and ten haplotypes were observed. The most frequent haplotypes (UTR-1, UTR-2, and UTR-3) accounted for â¼ 77% of haplotypes found in LL, while in the HL, the same haplotypes reach â¼ 93%. Also, a remarkable high frequency of putative ancestral UTR-5 haplotype was observed in LL (21.5%), while in HL UTR-2 reaches up to 47%. Further, UTR-2 frequency positively correlates with altitude-related variables, while a negative correlation for UTR-5 was observed. From an evolutionary perspective, we observed a tendency towards balancing selection in HL and LL populations thus suggesting that haplotypes of ancient and more derived alleles may have been co-opted for relatively recent adaptations such as those experienced by modern humans in the highland and lowland of South America. We also discuss how long-term balancing selection can be a reservoir of genetic variants that can be positively selected. Finally, our study provides some pieces of evidence that HLA-G 3'UTR haplotypes may have contributed to high altitude adaptation in the Andes.
Assuntos
Indígena Americano ou Nativo do Alasca , Antígenos HLA-G , Regiões 3' não Traduzidas/genética , Brasil , Frequência do Gene , Genótipo , Antígenos HLA-G/genética , Haplótipos , Humanos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Single nucleotide polymorphisms (SNPs) can have significant effects on phenotypic characteristics in cattle. MicroRNAs (miRNAs) are small, non-coding RNAs that act as post-transcriptional regulators by binding them to target mRNAs. In the present study, we scanned ~56 million SNPs against 1,064 bovine miRNA sequences and analyzed, in silico, their possible effects on target binding prediction, primary miRNA formation, association with QTL regions and the evolutionary conservation for each SNP locus. Following target prediction, we show that 71.6% of miRNA predicted targets were altered as a consequence of SNPs located within the seed region of the mature miRNAs. Next, we identified variations in the Minimum Free Energy (MFE), which represents the capacity to alter molecule stability and, consequently, miRNA maturation. A total of 48.6% of the sequences analyzed showed values within those previously reported as sufficient to alter miRNA maturation. We have also found 131 SNPs in 46 miRNAs, with altered target prediction, occurring in QTL regions. Lastly, analysis of evolutionary conservation scores for each SNP locus suggested that they have a conserved biological function through the evolutionary process. Our results suggest that SNPs in microRNAs have the potential to affect bovine phenotypes and could be of great value for genetic improvement studies, as well as production.
Assuntos
MicroRNAs/genética , Polimorfismo de Nucleotídeo Único , Regiões 3' não Traduzidas/genética , Animais , Bovinos , FenótipoRESUMO
Leprosy is a prevalent disease in Brazil, which ranks as the country with the second highest number of cases in the world. The disease manifests in a spectrum of forms, and genetic differences in the host can help to elucidate the immunopathogenesis. For a better understanding of MICA association with leprosy, we performed a case-control and a family-based study in two endemic populations in Brazil. MICA and HLA-B alleles were evaluated in 409 leprosy patients and in 419 healthy contacts by PCR-SSOP-Luminex-based technology. In the familial study, analysis of 46 families was completed by direct sequencing of all exons and 3'/5'untranslated regions, using the Ilumina MiSeq platform. All data were collected between 2006 and 2009. Statistical analysis was performed using the Chi-square or Fisher's exact test together with a multivariate analysis. Family-based association was assessed by transmission disequilibrium test (TDT) software FBAT 2.0.4. We found associations between the haplotype MICA*002-HLA-B*35 with leprosy in both the per se and the multibacillary (MB) forms when compared to healthy contacts. The MICA allele *008 was associated with the clinical forms of paucibacillary (PB). Additionally, MICA*029 was associated with the clinical forms of MB. The association of MICA*029 allele (MICA-A4 variant) with the susceptibility to the MB form suggests this variant for the transmembrane domain of the MICA molecule may be a risk factor for leprosy. Two MICA and nine HLA-B variants were found associated with leprosy per se in the Colônia do Prata population. Linkage disequilibrium analysis revealed perfect linkage disequilibrium (LD) between HLA-B markers rs2596498 and rs2507992, and high LD (R2 = .92) between these and the marker rs2442718. This familial study demonstrates that MICA association signals are not independent from those observed for HLA-B. Our findings contribute the knowledge pool of the immunogenetics of Hansen's disease and reveals a new association of the MICA*029 allele.
Assuntos
Antígenos HLA-B/genética , Antígenos de Histocompatibilidade Classe I/genética , Hanseníase/imunologia , Regiões 3' não Traduzidas/genética , Regiões 5' não Traduzidas/genética , Adolescente , Adulto , Alelos , Brasil/epidemiologia , Estudos de Casos e Controles , Criança , Doenças Endêmicas , Etnicidade/genética , Éxons/genética , Saúde da Família , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Haplótipos/genética , Humanos , Hanseníase/epidemiologia , Hanseníase/genética , Desequilíbrio de Ligação , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Domínios Proteicos , Adulto JovemRESUMO
Ezh2 is a catalytic subunit of the polycomb repressive complex 2 (PRC2) which mediates epigenetic gene silencing through depositing the mark histone H3 lysine 27 trimethylation (H3K27me3) at target genomic sequences. Previous studies have demonstrated that Enhancer of Zeste Homolog 2 (Ezh2) was differentially expressed during maturation of hippocampal neurons; in immature neurons, Ezh2 was abundantly expressed, whereas in mature neurons the expression Ezh2 was significantly reduced. Here, we report that Ezh2 is downregulated by microRNAs (miRs) that are expressed during the hippocampal maturation process. We show that, in mature hippocampal neurons, lethal-7 (let-7) and microRNA-124 (miR-124) are robustly expressed and can target cognate motifs at the 3'-UTR of the Ezh2 gene sequence to downregulate Ezh2 expression. Together, these data demonstrate that the PRC2 repressive activity during hippocampal maturation is controlled through a post-transcriptional mechanism that mediates Ezh2 downregulation in mature neurons.
Assuntos
Regulação para Baixo/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Hipocampo/fisiologia , MicroRNAs/genética , Neurônios/fisiologia , Regiões 3' não Traduzidas/genética , Animais , Linhagem Celular , Epigênese Genética/genética , Feminino , Células HEK293 , Histonas/genética , Humanos , Complexo Repressor Polycomb 2/genética , Gravidez , Interferência de RNA/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
Trypanosoma cruzi is the etiological agent of Chagas disease, which affects millions of people in Latin America. No transcriptional control of gene expression has been demonstrated in this organism, and 50% of its genome consists of repetitive elements and members of multigenic families. In this study, we applied a novel bioinformatics approach to predict new repetitive elements in the genome sequence of T. cruzi. A new repetitive sequence measuring 241 nt was identified and found to be interspersed along the genome sequence from strains of different DTUs. This new repeat was mostly on intergenic regions, and upstream and downstream regions of the 241 nt repeat were enriched in surface protein genes. RNAseq analysis revealed that the repeat was part of processed mRNAs and was predominantly found in the 3' untranslated regions (UTRs) of genes of multigenic families encoding surface proteins. Moreover, we detected a correlation between the presence of the repeat in the 3'UTR of multigenic family genes and the level of differential expression of these genes when comparing epimastigote and trypomastigote transcriptomes. These data suggest that this sequence plays a role in the posttranscriptional regulation of the expression of multigenic families.
Assuntos
Regiões 3' não Traduzidas/genética , Genoma de Protozoário , Sequências Repetitivas Dispersas , Proteínas de Membrana/metabolismo , Família Multigênica , Proteínas de Protozoários/genética , Trypanosoma cruzi/genética , Doença de Chagas/genética , Doença de Chagas/parasitologia , DNA de Protozoário/análise , DNA de Protozoário/genética , Regulação da Expressão Gênica , Humanos , Proteínas de Membrana/genética , Análise de Sequência de DNA , Trypanosoma cruzi/metabolismoRESUMO
Dyslipidemia has a substantial role in the development of acute coronary syndrome (ACS). Low-density lipoprotein receptor (LDLR) plays a critical role in plasma lipoprotein hemostasis, which is involved in the formation of atherosclerotic plaque. This study aimed to evaluate whether LDLR gene polymorphisms are significantly associated with ACS and the plasma lipids profile. Three LDLR gene polymorphisms located in the UTR'3 region (c.*52 A/G, c.*504 A/G, and c.* 773 A/G) were determined using TaqMan genotyping assays in a group of 618 ACS patients and 666 healthy controls. Plasma lipids profile concentrations were determined by enzymatic/colorimetric assays. Under co-dominant and recessive models, the c.*52 A allele of the c.*52 A/G polymorphism was associated with a higher risk of ACS (OR = 2.02, pCCo-dom = 0.033, and OR = 2.00, pCRes = 0.009, respectively). In the same way, under co-dominant and recessive models, the c.*773 G allele of the c.*773 A/G polymorphism was associated with a high risk of ACS (OR = 2.04, pCCo-dom = 0.027, and OR = 2.01, pCRes = 0.007, respectively). The "AAG" haplotype was associated with a high risk of ACS (OR = 1.22, pC = 0.016). The c.*52 AA genotype showed a lower HDL-C concentration than individuals with the GG genotype. In addition, carriers of c.*773 GG genotype carriers had a lower concentration of the high-density lipoprotein-cholesterol (HDL-C) than subjects with the AA genotype. Our data suggest the association of the LDLRc.*773 A/G and LDLR c.*52 A/G polymorphisms with both the risk of developing ACS and with a lower concentration of HDL-C in the study population.
Assuntos
Síndrome Coronariana Aguda/genética , HDL-Colesterol/sangue , Predisposição Genética para Doença , Receptores de LDL/genética , Regiões 3' não Traduzidas/genética , Síndrome Coronariana Aguda/sangue , Síndrome Coronariana Aguda/patologia , Idoso , Feminino , Estudos de Associação Genética , Variação Genética/genética , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
The aim of this study was to evaluate the association of single-nucleotide variant n.60G>C (rs2910164) of microRNA (miR)-146a, related to suppressing of BRCA1/2 DNA repair protein, with the risk and survival of colorectal cancer patients, as well as miR-146a and BRCA1/2 levels and miR binding efficiency. The genotypes were identified in 125 colorectal cancer patients and 276 controls using TaqMan polymerase chain reaction assay. The miR-146a and BRCA1/2 levels were assessed by quantitative-polymerase chain reaction protocols. Primary precursor of miR-146a containing G (wild-type) and C (variant) allele were cloned into pcDNA.3.3 vector and co-transfected in HT-29 colorectal cancer cell line. Luciferase reporter assay was performed to assess miR-146a binding to BRCA2 3'-untranslated region in HT-29. The differences between groups were calculated using chi-square or Fisher's exact test, logistic regression, and Mann-Whitney test. The prognostic impact of single-nucleotide variant genotypes on overall survival was evaluated by Kaplan-Meier estimate and Cox regression. The GC or CC genotypes prevalence was similar in patients and controls (50.4% vs 50.7%, p = 0.74). However, patients with tumors in advanced stage with miR-146a GG genotype had 2.41 more chance of dying than GC or CC genotypes. In addition, tumor tissues of patients with GG genotype presented higher miR-146a (p = 0.02) and lower BRCA1 (p = 0.01) and BRCA2 (p < 0.0001) levels when compared to those with GC or CC genotypes. In fact, pcDNA.3.3-miR-146a-G presented increased binding capacity to the 3'-untranslated region of BRCA2 (p = 0.001) compared to pcDNA.3.3-miR-146a-C. In addition, the G allele altered the binding affinity between miR-146a and its BRCA2 3'-untranslated region target (p < 0.001), thus enhancing suppression of BRCA2 expression. Our results suggest that single-nucleotide variant rs2910164 does not influence the colorectal cancer risk in Brazilian patients; however, the GG genotype could act as a factor of worse prognosis in patients with advanced disease due to suppression of BRCA1/2 modulated by miR-146a.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias Colorretais/genética , MicroRNAs/genética , Regiões 3' não Traduzidas/genética , Adulto , Alelos , Brasil/epidemiologia , Neoplasias Colorretais/patologia , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Estudos de Associação Genética , Predisposição Genética para Doença , Genótipo , Células HT29 , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Polimorfismo de Nucleotídeo Único/genética , Prognóstico , Ligação ProteicaRESUMO
Dengue virus (DENV) is a global health threat, causing repeated epidemics throughout the tropical world. While low herd immunity levels to any one of the four antigenic types of DENV predispose populations to outbreaks, viral genetic determinants that confer greater fitness for epidemic spread is an important but poorly understood contributor of dengue outbreaks. Here we report that positive epistasis between the coding and noncoding regions of the viral genome combined to elicit an epidemiologic fitness phenotype associated with the 1994 DENV2 outbreak in Puerto Rico. We found that five amino acid substitutions in the NS5 protein reduced viral genomic RNA (gRNA) replication rate to achieve a more favorable and relatively more abundant subgenomic flavivirus RNA (sfRNA), a byproduct of host 5'-3' exoribonuclease activity. The resulting increase in sfRNA relative to gRNA levels not only inhibited type I interferon (IFN) expression in infected cells through a previously described mechanism, but also enabled sfRNA to compete with gRNA for packaging into infectious particles. We suggest that delivery of sfRNA to new susceptible cells to inhibit type I IFN induction before gRNA replication and without the need for further de novo sfRNA synthesis could form a "preemptive strike" strategy against DENV.
Assuntos
Regiões 3' não Traduzidas/genética , Vírus da Dengue/genética , Dengue/virologia , Proteínas não Estruturais Virais/genética , Células A549 , Dengue/epidemiologia , Epistasia Genética , Exorribonucleases , Técnicas de Inativação de Genes , Genoma Viral , Células HEK293 , Interações Hospedeiro-Patógeno , Humanos , Interferon Tipo I/metabolismo , Proteínas Associadas aos Microtúbulos , Mutação , Porto Rico/epidemiologia , RNA Guia de Cinetoplastídeos/metabolismo , Replicação ViralRESUMO
Characterization of four novel HLA-DPA1*01:03:01 variants, HLA-DPA1*01:03:01:24, -DPA1*01:03:01:25, -DPA1*01:03:01:26, and -DPA1*01:03:01:27.
Assuntos
Cadeias alfa de HLA-DP/genética , Polimorfismo de Nucleotídeo Único , Obtenção de Tecidos e Órgãos , Regiões 3' não Traduzidas/genética , Alelos , Transplante de Medula Óssea , Brasil , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Teste de Histocompatibilidade/métodos , Humanos , Íntrons/genética , Masculino , Análise de Sequência de DNA/métodosRESUMO
Characterization of an HLA-B*15:10:01 variant, HLA-B*15:10:01:05.