This application for the Center for Structural Biology of HIV RNA (CRNA) focuses on determining the structural and mechanistic bases of HIV-1 RNA-related replication functions and the host’s response at the cellular, viral and atomic levels. Although considerable progress has been made over the past 40 years in understanding how proteins function in HIV-1 replication, comparatively little is known about how HIV-1 RNA structures, dynamics, trafficking, and interactions with proteins alternately enable or limit virus replication. The past decade has provided transformative examples of the therapeutic use of RNA and RNA-targeted therapies. Because HIV-1 RNA is exceptionally rich in biologic functions, and recent progress by members of the proposed team has begun to unlock structural and dynamic features of RNA elements in HIV-1, the potential for RNA-targeted approaches in the prevention, maintenance, and cure of HIV disease is highly compelling. However, this potential is limited by the general paucity of high-resolution structural information for RNA and protein-RNA complexes, which reflects inherent challenges in using RNA as a subject for structural analysis and the inadequacy of traditional biophysical approaches to address these challenges. The CRNA consists of a multidisciplinary team of structural biologists, chemists, cell and computational biologists, biochemists, immunologists and virologists. Many are leaders in the study of HIV-1 RNA and the roles of its structures in virus replication, while others are new to the HIV field and bring a fresh perspective and complementary expertise. Together, this team brings cutting edge technologies and incisive biologic approaches to overcome current technological obstacles, enabling mechanistic determination of the role of HIV-1 RNA structures and associated proteins in viral transcription, splicing, translation, packaging, particle assembly, and interactions with host factors. These studies will enable the CRNA to advance goals of clinical relevance, including the development of novel classes of antiviral compounds, design of new strategies for the reactivation of latent proviruses, and the augmentation of host defenses against HIV infection. These studies will also result in the development of powerful new techniques that can be applied to all areas of RNA biology.