Biology subjects

Avinens, D.

Publications and source records attributed to Avinens, D..

3 recordsLinked to original sources

bioRxiv2026

SARS-CoV-2 nucleocapsid protein engages with viral RNA and ERGIC lipids to drive viral core assembly

Severe acute respiratory syndrome coronavirus 2 assembles at the ER-Golgi intermediate compartment (ERGIC), yet the molecular basis of nucleocapsid (N) protein interactions with host membranes remains unclear. Using in vitro reconstituted lipid membranes and viral RNA- N complexes, we show that full-length N binds phosphatidylinositol (PI)- and phosphatidylserine (PS)-containing membranes and induces lipid clustering, an effect amplified by viral RNA and ERGIC-like membrane lipid composition. The isolated N-terminal domain lacks this activity, whereas the C-terminal domain retains membrane-associated multimerization. Although, lipid bilayers promote co-clustering of N and PI lipids, facilitating ribonucleoprotein (RNP) assembly, even on simple membranes. Importantly, ERGIC- mimicking membranes enhances this co-clustering further stabilizing RNPs of dimensions matching the viral core. In cells, viral RNA enhances N clustering without altering particle production. These findings reveal cooperative interactions between N, viral RNA, and ERGIC lipids as key drivers of lipid-dependent viral core formation, providing a mechanistic framework for the early steps of viral assembly.

biophysics↗

bioRxiv2026

Real-time single-molecule imaging in zebrafish embryos uncovers non-canonical translation

Precise spatiotemporal control of protein synthesis is essential during embryogenesis, yet directly measuring translation kinetics in vivo remains challenging in vertebrates. In particular, it remains unclear how translation efficiency is determined for key developmental regulators, and which kinetic steps limit their production. Here, we used ALFA array-based nascent chain labeling combined with lattice light-sheet microscopy to visualize bmp2b translation in real time and at single-molecule resolution in early zebrafish embryos. When combined with MS2/MCP labeling to visualize all bmp2b mRNAs, we found that only some of them are being actively translated, suggesting that limited mRNA translation competence contributes to overall translation efficiency. We found that bmp2b translation operates below a maximal initiation regime, as replacement of its UTRs with viral UTRs increases ribosome loading. Furthermore, the bmp2b, but not actb2, 5'UTR supports cap-independent translation with ribosome loading comparable to cap-dependent initiation. Altogether, this approach provides a quantitative in vivo framework to dissect translation kinetics during early vertebrate development.

developmental biology↗

bioRxiv2023

Recruitment of apolipoprotein E facilitates Herpes simplex virus 1 release

Over two decades, epidemiological studies have revealed that interactions between human polymorphic apolipoprotein 4 (ApoE, isoform 4) and herpes simplex virus type 1 (HSV1) associate with higher risk of Alzheimers disease, a serious and increasing issue among elder populations worldwide. Nevertheless, little is known about the mechanisms behind ApoE-HSV1 interactions at molecular levels. Here, we investigate the effects of ApoE on the HSV1 infectious life cycle in in vitro cell experiments. Analysis of HSV1 growth curves shows that HSV1 production is promoted in presence of any of the three ApoE isoforms, with ApoE 3 or 4 demonstrating more proviral effects than ApoE 2. Quantification by qPCR reveals that the presence of ApoE 2, 3, or 4 leads to an increase of HSV1 extracellular release but unchanged levels of viral genome copies within cells or on the cell surface, indicating that virus replication, assembly, or transport to cell membrane are not affected. Further test of virus release directly demonstrates that HSV1 detachment from the cell surface is promoted by ApoE. Subsequent results reveal that ApoE is both present in purified HSV1 particles produced in ApoE-expressing cells after ultra-centrifugation and able to incorporate into HSV1 particles after purification, suggesting that harbouring ApoE may play a key role in the pro-viral effect of ApoE. Along these lines, we tested the infectious behaviour of ApoE-coated viruses and observed faster attachment kinetics and higher entry efficiencies of ApoE decorated HSV1. Our hypothesis that the association with ApoE leads to modified interactions of the virus with the cell membrane during entry and egress, was further validated in biophysical experiments. In such experiments, HSV1-membrane interaction kinetics and apparent affinity between HSV1 and native supported lipid bilayers (a plasma membrane mimic) were quantified using total internal reflection microscopy. HSV1 particles decorated with ApoE demonstrate both higher association (kon) and dissociation rate constants (koff), as well as less irreversible binding to the membrane, which is in line with the biological experiments. Overall, our results provide new insights into the roles of ApoE during HSV1 infections, which is worth to be considered when studying their involvement during Alzheimers disease development.

microbiology↗