Project Summary
Ribonucleoprotein (RNP) granules are cellular membrane-less organelles comprised of RNA and
RNA binding proteins (RBPs), which form through the biophysical principle of condensation or liquid-liquid
phase separation (LLPS). An interesting group of cytosolic RNP granules are stress granules (SGs), that
form upon a variety of different stressors. Stress leads to a global translation inhibition, causing exposed
untranslating RNAs to condense and aggregate into SGs. Mutations in various SG proteins lead to aberrant
and constitutive SGs or RNP aggregates. Such RNP aggregates are associated with amyotrophic lateral
sclerosis (ALS), frontotemporal dementia (FTD), and various muscular dystrophies. Therefore, it is of high
medical need to understand the principles of RNP granule assembly and disassembly.
While the properties, mechanisms and functions of SGs are highly studied, nothing is known about
if, and how, SGs couple transcriptional and posttranscriptional mechanisms. Therefore, my research
objectives focus on characterizing how SGs and/or the SG assembly scaffold protein G3BP1 regulate
transcription, thereby coupling cytosolic and nuclear stress responses to maintain cellular homeostasis. In
this application, I combine genome-wide, computational and experimental approaches to 1) determine if
transcription is affected by the formation of SGs and identify SG target genes, 2) characterize the detailed
mechanism by which SGs mediate transcriptional changes, and 3) examine nuclear functions of G3BP1
including possible direct roles in regulating transcription.
During the K99 phase, under the mentorship of Dr. Roy Parker and Dr. Robin Dowell, comprehensive
approaches using genome-wide data analysis and cellular techniques will be used to determine if SGs
regulate transcription, identify SG target genes, and elucidate the detailed mechanism of this regulatory
pathway. With support from Dr. Amy Palmer, expertise in analyzing the role of SGs and/or G3BP1 in
metal/ion homeostasis will be acquired in order to identify if SGs and/or G3BP1 regulate metal/ion
homeostasis during stress response on the transcriptional level. Further, expertise from Dr. John Rinn in
studying the role of RNA in chromatin recognition will advance characterizing G3BP1 and the importance
of RNA in G3BP1-chromatin binding.
Additional K99 training in genomic techniques and computational analysis will be essential for the
proposed research and advance my transition into and progress during the independent R00 phase.
The results of this proposal will not only lead to identification of important SG and G3BP1 function,
but also provide a fundamental understanding of how RNP granules couple cytosolic and nuclear stress
responses.