Biology subjects

Budnik, V.

Publications and source records attributed to Budnik, V..

3 recordsLinked to original sources

bioRxiv2024

Upregulation of FasII underlies synergistic neuropathological and behavioral defects in a Drosophila model of myotonic dystrophy

Myotonic dystrophy type 1 (DM1) is a multisystemic disorder that has been extensively studied for decades, yet our understanding of its neuropathological aspect remains rudimentary. In this study, we characterized a novel model of DM1 neuropathology by expressing untranslated expanded CUG repeats at the Drosophila larval neuromuscular junction. In this model, both pre- and postsynaptic expression of CUG repeats participate to induce reduction of synaptic boutons, increase of arbor disassembly and impairment of larval locomotor activity. We found that the expression of CUG repeats caused an upregulation of the cell adhesion molecule, FasII (NCAM1 in mammals), in both the motor neurons and the body wall muscles. Knockdown of fasII was sufficient to rescue bouton numbers and locomotor impairment in this model. Further analyses identified the upregulation of the FasII-C isoform as a major contributor of these phenotypes. Remarkably, overexpressing the FasII-A-PEST+ isoform rescued the synaptic and behavioral defects, likely by outcompeting the upregulated FasII-C. Our study provided the foundation for a basic mechanism of synapse dysregulation in DM1.

neuroscience↗

bioRxiv2023

Dueling Endogenous Viral-Like Sequences Control Synaptic Plasticity

The function of a large part of most genomes, generally called "junk DNA", remains largely unknown. Much of this enigmatic DNA corresponds to transposons, which are considered genomic parasites. Here, we show the protein of the Ty1 retrotransposon Copia is enriched at the Drosophila neuromuscular junction and is transported across synapses. Unexpectedly, disrupting Copia expression results in increases in both synapse development and structural synaptic plasticity. Plasticity is kept in balance as Copia antagonizes the Drosophila Arc (activity-regulated cytoskeleton-associated protein) homolog, which is a transposon-derived gene. Our cryo-EM structure of the Copia capsid shows a shell with large cargo capacity and leads to a hypothesis for mutual antagonism of Arc and Copia capsid assembly. Our findings provide evidence that a fully functional transposon plays a role at synapses, suggesting that transposons and other types of junk DNA are essential to developmental and cellular processes.

neuroscience↗

bioRxiv2017

Nuclear Export Through Nuclear Envelope Remodeling in Saccharomyces cerevisiae

In eukaryotes, subsets of exported mRNAs are organized into large ribonucleoprotein (megaRNP) granules. How megaRNPs exit the nucleus is unclear, as their diameters are much larger than the nuclear pore complex (NPC) central channel. We previously identified a non-canonical nuclear export mechanism in Drosophila (Speese et al., Cell 2012) and mammals (Ding et al., in preparation), in which megaRNPs exit the nucleus by budding across nuclear envelope (NE) membranes. Here, we present evidence for a similar pathway in the nucleus of the budding yeast S. cerevisiae, which contain morphologically similar granules bearing mRNAs. Wild-type yeast displayed these granules at very low frequency, but this frequency was dramatically increased when the non-essential NPC protein Nup116 was deleted. These granules were not artifacts of defective NPCs; a mutation in the exportin XPO1 (CRM1), in which NPCs are normal, induced similar megaRNP upregulation. We hypothesize that a non-canonical nuclear export pathway, analogous to those observed in Drosophila and in mammalian cells, exists in yeast, and that this pathway is upregulated for use when NPCs or nuclear export are impaired.\n\nSUMMARYDing et al., describe a non-canonical mRNA export pathway in budding yeast similar to that observed in Drosophila. This pathway appears upregulated when the NPC is impaired, nuclear envelope integrity is disrupted, or the export factor Xpo1 (CRM1) is defective.

cell biology↗