Role of eIF4A proteins in miR-122 mediated Hepatitis C virus regulation

An estimated 2-3% of the global population is living with Hepatitis C virus (HCV) infection and 60-90% of these infections become chronic, which could leads to cirrhosis and liver cancer. While new antiviral therapies are emerging, a better understanding of how HCV interacts with host cells is important. HCV is a hepatotropic positive sense RNA virus. The HCV 5’ untranslated region (UTR) contains two binding sites for a highly abundant liver-specific microRNA, miR-122. In contrast to the canonical function for microRNAs in binding to 3’UTR sites, leading to mRNA degradation and translational repression, HCV uses miR-122 as an essential positive regulator of viral replication. The mechanism of this regulation remains uncertain, with viral translation, RNA stability and replication all implicated in different studies. In order to understand the mechanism of HCV regulation by miR-122, it is important to identify the host protein factors involved in this regulation. This thesis investigates the role for eukaryotic initiation factor 4A (eIF)4AII, which preliminary studies implicated in HCV replication and which has also been shown to function in miRNA activity. eIF4AI and eIF4AII are ATP-dependent helicases, which linearize secondary structures present in the 5’ UTR of an mRNA and help ribosome binding to the mRNA and scanning for initiation codon. Eukaryotic initiation factor (eIF)4AII has been described as a binding partner of HCV RNA polymerase enzyme (NS5B) by binding to NS5B’s C-terminal residues and is also involved in miRNA regulation of translation at 3’UTR sites. eIF4AI and eIF4AII have more than 90% sequence similarity due to which these proteins have long been functionally interchangeable. However, eIF4AII depletion had no effect on cellular growth while eIF4AI depletion was shown to be inhibitory to cellular growth. Unlike eIF4AII, eIF4AI role in miRNA regulation at 3’UTR sites is unknown. In this thesis, depletion of eIF4AII is shown to lead to a reduction in HCV RNA level, while eIF4AI knockdown had variable effects on HCV RNA levels. These variabilities could be due to the subtle differences in the confluence levels of cells or due to the experimental variability. These findings also support the idea that eIF4AI and eIF4AII function differently. In order to study whether this reduction in HCV RNA levels in eIF4AII depleted cells is linked with miR-122 regulation of HCV, sequestration, and overexpression of miR-122 in eIF4AII depleted cells were performed. We have been able to show that the presence or absence of miR-122 did not change the HCV RNA levels in eIF4AII depleted cells, which suggests that eIF4AII contribution to HCV replication is linked with miR-122 regulation of HCV and functional eIF4AII is required for miR-122 mediated regulation of HCV. However, eIF4AII did not affect miR-122 regulation of luciferase reporters in which the HCV 5'UTR controls luciferase translation. By co-immunoprecipitation, eIF4AII is shown to interact with HCV RNA and miR-122 in a miR-122-dependent manner. eIF4AII also interacts with miR-21 and miR-26a, but this interaction is not dependent on miR-122, indicating that miR-122 is specifically required for the eIF4AII-HCV RNA interaction. DDX6 and eIF4AII have been proposed to be involved in miRNA mediated repression by Ccr4-Not complex via CNOT1. The involvement of eIF4AII in miRNA mediated repression was questioned in a different study in which the interaction between eIF4AII and CNOT1 was not confirmed. siRNA based knockdown of CNOT1 reduces both HCV RNA and miR-122 co-immunoprecipitation with eIF4AII, which indicates that Ccr4-NOT complex component CNOT1 contributes to eIF4AII association with miR-122 and HCV and may be part of the same complex. Taken together, eIF4AII is identified a new host factor that is important for HCV replication, and that requires miR-122 to interact with HCV RNA, but it was not possible to demonstrate conclusively that eIF4AII regulates HCV by modulation of miR-122 activity

Eukaryotic translation initiation factor 4All contributes to microRNA-122 regulation of hepatitis C virus replication

Hepatitis C virus (HCV) is a positive sense RNA virus that persistently infects human liver, leading to cirrhosis and hepatocellular carcinoma. HCV replication requires the liver-specific microRNA-122 (miR-122). In contrast to canonical miRNA-mediated repression via 3’UTR sites, miR-122 positively regulates HCV replication by a direct interaction with the 5’ untranslated region (UTR) of the viral RNA. The protein factor requirements for this unusual miRNA regulation remain poorly understood. Here, we identify eIF4AII, previously implicated in miRNA-mediated repression via 3’UTR sites, as a host factor that is important for HCV replication. We demonstrate that eIF4AII interacts with HCV RNA and that this interaction is miR-122-dependent. We show that effective miR-122 binding to, and regulation of, HCV RNA are reduced following eIF4AII depletion. We find that the previously identified HCV co-factor CNOT1, which has also been implicated in miRNA-mediated repression via 3’UTR sites, contributes to regulation of HCV by eIF4AII. Finally, we show that eIF4AI knockdown alleviates the inhibition of HCV replication mediated by depletion of either eIF4AII or CNOT1. Our results suggest a competition effect between the eIF4A proteins to influence HCV replication by modulation of miR-122 function

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia

Search for top squark pair production in pp collisions at root s=13 TeV using single lepton events

Peer reviewe

Search for new physics with dijet angular distributions in proton-proton collisions at root S = 13 TeV

Peer reviewe

Search for narrow resonances in dilepton mass spectra in proton-proton collisions at root s=13 TeV and combination with 8 TeV data

Peer reviewe

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis