The nuclear pore protein NUP98 impedes LTR-driven basal gene expression of HIV-1, viral propagation, and infectivity

Nucleoporins (NUPs) are cellular effectors of human immunodeficiency virus-1 (HIV-1) replication that support nucleocytoplasmic trafficking of viral components. However, these also non-canonically function as positive effectors, promoting proviral DNA integration into the host genome and viral gene transcription, or as negative effectors by associating with HIV-1 restriction factors, such as MX2, inhibiting the replication of HIV-1. Here, we investigated the regulatory role of NUP98 on HIV-1 as we observed a lowering of its endogenous levels upon HIV-1 infection in CD4+ T cells. Using complementary experiments in NUP98 overexpression and knockdown backgrounds, we deciphered that NUP98 negatively affected HIV-1 long terminal repeat (LTR) promoter activity and lowered released virus levels. The negative effect on promoter activity was independent of HIV-1 Tat, suggesting that NUP98 prevents the basal viral gene expression. ChIP-qPCR showed NUP98 to be associated with HIV-1 LTR, with the negative regulatory element (NRE) of HIV-1 LTR playing a dominant role in NUP98-mediated lowering of viral gene transcription. Truncated mutants of NUP98 showed that the attenuation of HIV-1 LTR-driven transcription is primarily contributed by its N-terminal region. Interestingly, the virus generated from the producer cells transiently expressing NUP98 showed lower infectivity, while the virus generated from NUP98 knockdown CD4+ T cells showed higher infectivity as assayed in TZM-bl cells, corroborating the anti-HIV-1 properties of NUP98. Collectively, we show a new non-canonical function of a nucleoporin adding to the list of moonlighting host factors regulating viral infections. Downregulation of NUP98 in a host cell upon HIV-1 infection supports the concept of evolutionary conflicts between viruses and host antiviral factors

UI driven dynamic analysis and testing of web applications

Modern web applications have evolved to become highly complex, interact-able software capable of replicating the functionalities of traditional software. The web application development itself evolved to present a variety of options in terms of development frameworks and programming languages available to the developers. This however, also leads to one of core challenges in web application testing, the heterogenous nature of web applications, which makes software testing techniques that rely on analyzing source-code ineffective. Instead, end-to-end UI testing is the preferred mode of ensuring the web applications do not contain faults or bugs. However, the web UI testing ecosystem has failed to evolve at a similar pace to web development but instead relies on human effort in practice, making web application testing a costly endeavour. The goal of this thesis is to enable automatic testing of web applications reducing reliance on human effort. First, we identified web page equivalence to be a core challenge faced by existing automatic UI test generation techniques, performed an empirical evaluation of ten existing state comparison techniques and identified the characteristics of modern web apps that render these techniques ineffective in generating optimal UI test suites. Thereafter, we designed a novel state comparison and test generation technique which treats a web page as a set of individual functionalities that can be represented in a hierarchy of fragments, helping us test modern web applications in an effective manner. Next, we designed the first universally applicable mutation analysis framework for web applications regardless of the back-end and front-end technologies they were built upon. It is capable of assessing the quality of a given UI test suite without even requiring the source-code of the web application. Finally, we tackle the challenge of enabling API testing universally for any web application. Our API testing framework exercises the UI to carve API test suites and generates API specification that would enable API testing for any given web application. We implement our techniques in open-source tools and evaluate them through a set of controlled experiments. The results show that our techniques succeeded in accomplishing the set research goals.Applied Science, Faculty ofElectrical and Computer Engineering, Department ofGraduat

Approaches and Tools for Automated End-to-End Web Testing

The importance of test automation in web engineering comes from the widespread use of web applications and the associated demand for code quality. Test automation is considered crucial for delivering the quality levels expected by users, since it can save a lot of time in testing and it helps developers to release web applications with fewer defects. The main advantage of test automation comes from fast, unattended execution of a set of tests after some changes have been made to a web application. Moreover, modern web applications adopt a multitier architecture where the implementation is scattered across different layers and run on different machines. For this reason, end-to-end testing techniques are required to test the overall behavior of web applications.In the last years, several approaches have been proposed for automated end-to-end web testing and the choice among them depends on a number of factors, including the tools used for web testing and the costs associated with their adoption. They can be classified using two main criteria: the first concerns how test cases are developed (ie, Capture-Replay and Programmable approaches), while, the second concerns how test cases localize the web elements to interact with (ie, Coordinates-based, DOM-based, and Visual approaches), that is what kind of locators are used for selecting the target GUI components.For developers and project managers it is not easy to select the most suitable automated end-to-end web testing approach for their needs among the existing ones. This chapter provides a comprehensive overview of the automated end-to-end web testing approaches and summarizes the findings of a long term research project aimed at empirically investigating their strengths and weaknesses. \ua9 2016 Elsevier Inc

Three Open Problems in the Context of E2E Web Testing and a Vision: NEONATE

Web applications are critical assets of our society and thus assuring their quality is of undeniable importance. Despite the advances in software testing, the ever-increasing technological complexity of these applications makes it difficult to prevent errors. In this work, we provide a thorough description of the three open problems hindering web test automation: fragility problem, strong coupling and low cohesion problem, and incompleteness problem. We conjecture that a major breakthrough in test automation is needed, because the problems are closely correlated, and hence need to be attacked together rather than separately. To this aim, we describe NEONATE, a novel integrated testing environment specifically designed to empower the web tester. Our utmost purpose is to make the research community aware of the existence of the three problems and their correlation, so that more research effort can be directed in providing solutions and tools to advance the state of the art of web test automation