Fellowship for Sukanya Srinivasan: Investigating the role of RNA helicase DHX36 in modulating aberrant RNA condensation

Project Summary Stress granules (SGs) are transient cytoplasmic ribonucleoprotein (RNP) granules formed in response to cellular stress. SGs play crucial roles in regulating RNA metabolism and promoting cell survival, but their persistence can be cytotoxic and contribute to neurodegenerative diseases. Stable RNA G-quadruplex structures (rGQs) are involved in SG formation and can in?uence their biophysical properties to form either liquid- or solid-like assemblies. Hence, aberrant accumulation of rGQs can compromise SG dissolution upon removing stress, resulting in SG persistence. The primary focus of this application is to investigate how the RNA helicase DHX36, known for its ability to remodel rGQs, in?uences SG dissolution and aging dynamics. The proposal is structured around three speci?c aims. Aim 1 will examine how altering DHX36 levels and perturbing its ATP/RNA binding ability a?ects SG aging dynamics, with a hypothesis that DHX36-mediated remodeling of rGQs in SGs is necessary for maintaining the ?uidity of SGs and preventing their transition to solid-like, potentially harmful states. Using live-cell imaging and quantitative biophysical methods, we will track SG disassembly kinetics following stress exposure and DHX36 manipulation. Aim 2 focuses on understanding how DHX36 a?ects SG biophysical properties and aging dynamics, by employing optical tweezer-based nano-rheology approaches in an in vitro lysate-based stress granule system. Aim 3 will assess DHX36’s ability to remodel aberrant RNA condensation, particularly in the context of neurological diseases such as ALS, where repeat expansion RNAs form toxic condensates. Using bottom-up reconstitution of RNP condensates, this aim will test a hypothesis that DHX36 can chaperone intra-condensate liquid-to-solid phase transitions of repeat RNAs. By combining innovative biochemical, biophysical, and live-cell imaging approaches, this research aims to provide novel insights into the cellular mechanisms that regulate SG dynamics and RNA condensation. The ?ndings could have broad implications for understanding RNP granule aging and may lead to potential therapeutic strategies for neurodegenerative disorders associated with aberrant RNP granules. The fellowship will be conducted at the University of Bu?alo in the laboratory of Dr. Priya Banerjee, a leading researcher in the biophysics and biology of RNA-protein phase separation. This environment provides access to cutting-edge biophysical tools and a collaborative, interdisciplinary training environment, ensuring comprehensive preparation for an independent research career.