bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2021.08.30.458106

Flanking sequences regulate the toxicity, non-ATG translation, and aggregation of RNA with tandem CAG Repeats

Das, M. R.·Chang, Y.·Saunders, R.·Zhang, N.·Tomberlin, C.·Vale, R. D.·Jain, A.
View original source ↗Export metadata ↓

Abstract

Nucleotide repeat-expansions cause several neurodegenerative disorders, including Huntingtons disease and spinocerebellar ataxia. The expanded repeat-containing RNA transcribed from the affected loci agglomerate in the nucleus as pathogenic foci. Here we demonstrate that depending on their surrounding sequence context, RNAs with expanded CAG repeats can also undergo nuclear export and aggregate in the cytoplasm. Cytoplasmic aggregation of repeat-containing RNA coincides with several disease hallmarks, including repeat-associated non-AUG (RAN) translation, mislocalization of RNA binding proteins, and cell toxicity. Interestingly, the repeat-containing RNA co-aggregate with RAN translation products. Inhibition of RAN translation prevents cytoplasmic RNA aggregation and also alleviates cell toxicity. Our findings provide a cogent explanation for aberrant cytoplasmic localization of RNA binding proteins and implicate cis-acting flanking sequences in mediating RAN translation and disease.

Explore related subjects

molecular biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Das, M. R., Chang, Y., Saunders, R., Zhang, N., Tomberlin, C., Vale, R. D., Jain, A.. 2021-08-31. Flanking sequences regulate the toxicity, non-ATG translation, and aggregation of RNA with tandem CAG Repeats. https://doi.org/10.1101/2021.08.30.458106

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Engineered Miniature ParTasR Enables Efficient PAMless Genome Editing

TIGR-Tas system holds great promise for genome-engineering applications owing to its compact size and PAMless targeting capability. However, its low editing efficiency in mammalian cells severely limits its broader utility. Here, we engineered a highly active variant of ParTasR, termed eTasR, through structure-guided rational design of ParTasR combined with fusion to the exonuclease TREX2. eTasR increased mammalian editing efficiency from the original 4.29% to 48.94% with an average 26.52-fold increase, significantly surpassing the efficiency of SpRY, a reported version of PAM-free nuclease. More importantly, single-AAV delivery enabled efficient Hpd disruption in vivo, resulting in robust phenotypic rescue. Thus, eTasR provides a compact, PAMless and highly efficient platform for genome editing and therapeutic applications.

molecular biology↗
bioRxiv2026

Enhancing pancreatic islet cell survival via NMDAR antagonist-driven ROR1 activation as revealed by phosphoproteomics

NMDA receptors (NMDARs) control function and survival not only of neurons, but also of insulin-producing pancreatic beta cells. Since insufficient insulin secretion and beta cell death are key events during diabetes development, targeting NMDARs offers a therapeutic approach. Specifically, the NMDAR antagonist dextrorphan (DXO) increases glucose-stimulated insulin secretion in clinical trials. Furthermore, treatment with DXO or optimized DXO derivatives prevents pancreatic islet cell death upon diabetogenic insults. Nonetheless, the signaling pathways induced by NMDAR inhibition are poorly understood. Here, we use complementary approaches, phosphoproteomics and tyrosine kinase profiling, to demonstrate that DXO and its derivatives rapidly regulate multiple intracellular signaling clusters, including mTOR and ERK signaling, in pancreatic islets. Notably, mTOR inhibition, but not ERK inhibition, is sufficient to negate DXO's protective effects. Further, we show that activation of Receptor Tyrosine Kinase-like Orphan Receptor 1 (ROR1) is a universal event upon NMDAR inhibition in islets. Simultaneous knockdown of Ror1/ROR1 and its paralogue Ror2/ROR2 compromises the viability of both mouse and human islets, highlighting the ROR1/2 signaling axis as a promising avenue for enhancing beta cell survival.

molecular biology↗
bioRxiv2026

An ssRNA Phage Single-gene Lysis Protein Targeting MraY Reveals Convergent Evolution Across the RNA-DNA Phage Boundary

Small lytic phages of the ssRNA Leviviricetes and ssDNA Microviricetes achieve host lysis by expression of a single protein, designated as an Sgl protein. Four ssRNA Sgls have been shown to inhibit steps in peptidoglycan biosynthesis: three target MurJ, the Lipid II flippase, and one targets MurA, the committed step of the pathway. A fifth Sgl, the E protein of the canonical ssDNA microvirus {varphi}X174, inhibits MraY, which catalyzes the synthesis of the first lipid-linked intermediate. This inhibition requires SlyD, a cytoplasmic FKBP-type peptidyl-prolyl cis-trans isomerase. The Sgl of the Caulobacter ssRNA phage {varphi}Cb5 (Cebevirus halophobicum) has not been characterized. Here, we present physiological evidence that Sgl{varphi}Cb5 targets MraY. Moreover, we show that, despite the absence of detectable sequence similarity, Sgl{varphi}Cb5 shares several features with the {varphi}X174 E protein, including the distribution of hydrophobic and charged residues, a proposed N-out, C-in membrane topology, and retention of lytic activity in an Sgl{varphi}Cb5 -LacZ fusion. Furthermore, expression of the Caulobacter cytoplasmic FKBP-type peptidyl-prolyl cis-trans isomerase CC2799 enhances Sgl{varphi}Cb5 -mediated lysis in E. coli. These parallels between Sgl function in a DNA phage and an RNA phage either represent remarkably consonant convergent evolution or some evolutionary cross-over event for which there is currently no precedent.

molecular biology↗