Biology subjects

Rothacher, R. L.

Publications and source records attributed to Rothacher, R. L..

2 recordsLinked to original sources

bioRxiv2025

Massively parallel characterization of RNA G-quadruplex stability and molecular recognition

RNA G-quadruplexes (rG4s) have been implicated as important regulators of RNA metabolism and are promising targets for RNA-targeted therapeutics. rG4s typically require a canonical (G[≥]2N1-7)4 motif, but the sequence features that affect rG4 stability and recognition by RNA-binding proteins (RBPs) and rG4-binding ligands are not fully understood. To interrogate sequence-level drivers of rG4 folding, we applied a reverse-transcriptase stop sequencing strategy to a library of [~]3,000 synthetic rG4s with varied G-tract lengths, loop lengths, and loop compositions, permitting massively parallel quantification of rG4 stability. Our data confirm known sequence-level features and characterize novel combinatorial impacts of these features. We also assessed systematically mutagenized natural rG4s, revealing unexpected mutations that significantly affect rG4 stability, including contributions from flanking sequences outside of the rG4. We further used our strategy to assess rG4 recognition preferences of the model rG4- ligand pyridostatin, revealing a preferential stabilization of rG4s containing mixed-length G-tracts. We further demonstrated the potential for large-scale protein binding assays with our library to reveal rG4 features recognized by RBPs, specifically G3BP1 and FMRP. Our approach and data provide a generalizable framework to study sequence-level drivers of rG4 stability, binding by RBPs, and ligand interactions, defining basic principles of rG4 formation and downstream biology.

biochemistry↗

bioRxiv2025

5-ethynyluridine perturbs nuclear RNA metabolism to promote the nuclear accumulation of TDP-43 and other RNA binding proteins

TDP-43, an essential nucleic acid binding protein and splicing regulator, is broadly disrupted in neurodegeneration. TDP-43 nuclear localization and function depend on the abundance of its nuclear RNA targets and its recruitment into large ribonucleoprotein complexes, which restricts TDP-43 nuclear efflux. To further investigate the interplay between TDP-43 and nascent RNAs, we aimed to employ 5-ethynyluridine (5EU), a widely used uridine analog for click chemistry labeling of newly transcribed RNAs. Surprisingly, 5EU induced the nuclear accumulation of TDP-43 and other RNA-binding proteins and attenuated TDP-43 mislocalization caused by disruption of the nuclear transport apparatus. RNA FISH demonstrated 5EU-induced nuclear accumulation of polyadenylated and GU-repeat-rich RNAs, suggesting increased retention of both processed and intronic RNAs. TDP-43 eCLIP confirmed that 5EU preserved TDP-43 binding at predominantly GU-rich intronic sites. RNAseq revealed significant 5EU-induced changes in alternative splicing, accompanied by an overall reduction in splicing diversity, without any major changes in RNA stability or TDP-43 splicing regulatory function. These data suggest that 5EU may impede RNA splicing efficiency and subsequent nuclear RNA processing and export. Our findings have important implications for studies utilizing 5EU and offer unexpected confirmation that the accumulation of endogenous nuclear RNAs promotes TDP-43 nuclear localization.

cell biology↗