Biology subjects

Wan, X.-f.

Publications and source records attributed to Wan, X.-f..

3 recordsLinked to original sources

bioRxiv2026

Structure of influenza D virus NS1 reveals a novel Zn-binding site and ssRNA-binding activity

Influenza D virus (IDV) is an emerging pathogen associated with bovine respiratory disease and has potential for zoonotic transmission. Although nonstructural protein 1 (NS1) is a major virulence factor in influenza A and B viruses, the structure and function of IDV NS1 remain poorly defined. Here, we determined crystal structures of the IDV NS1 N-terminal RNA-binding domain (NTD) and C-terminal effector domain (CTD). The NTD retains the conserved homodimeric six-helix fold, whereas the CTD adopts a distinct architecture containing a novel Zn2+-binding site. IDV NS1 CTD preferentially binds single-stranded RNA, and mutagenesis identified lysine and arginine residues critical for this activity. Single-residue substitutions disrupting either the Zn2+-binding site or RNA-binding interface prevented recovery of infectious recombinant IDV. These findings reveal distinct structural and functional features of IDV NS1 and establish the importance of CTD integrity for viral replication. Conservation of key CTD residues in influenza C virus NS1 suggests shared structural features that distinguish influenza C and D virus NS1 proteins from their influenza A and B counterparts.

biochemistry↗

bioRxiv2025

Poor sleep impairs immune responses and influenza vaccine protection

Disrrupted sleep, a common occurrence among shift workers, older adults, and individuals with sleep disorders, is increasingly recognized as a potential factor interfering with vaccine efficacy. Using a mouse model, we show that two weeks of chronic sleep fragmentation (CSF) before and during influenza vaccination significantly impair humoral immunity and reduce protection against lethal viral challenge. CSF-exposed mice exhibited lower neutralizing antibody titers, diminished IgG subclass responses, and reduced survival after viral challenge, despite preserved antibody binding avidity. Single-cell RNA sequencing and immune receptor profiling revealed altered B cell maturation, abnormal germinal center activation, and plasma cell stress, characterized by activation of unfolded protein response and oxidative stress pathways. CSF also reprogrammed B-cell signaling and disrupted coordination with T-cells. Together, this study showed that CSF compromises vaccine-induced immune responses by affecting multistage of B-cell differentiation, underscoring the importance of considering sleep health in vaccination strategies for vulnerable populations. One Sentence SummaryPoor sleep weakens both the magnitude and quality of immune responses, compromising the protective efficacy of influenza vaccination.

immunology↗

bioRxiv2020

Measuring site-specific glycosylation similarity between influenza A virus variants with statistical certainty

Influenza A virus (IAV) mutates rapidly, resulting in antigenic drift and poor year-to-year vaccine effectiveness. One challenge in designing effective vaccines is that genetic mutations frequently cause amino acid variations in IAV envelope protein hemagglutinin (HA) that create new N-glycosylation sequons; resulting N-glycans cause antigenic shielding, allowing viral escape from adaptive immune responses. Vaccine candidate strain selection currently involves correlating antigenicity with HA protein sequence among circulating strains, but quantitative comparison of site-specific glycosylation information may likely improve the ability to design vaccines with broader effectiveness against evolving strains. However, there is poor understanding of the influence of glycosylation on immunodominance, antigenicity, and immunogenicity of HA, and there are no well-tested methods for comparing glycosylation similarity among virus samples. Here, we present a method for statistically rigorous quantification of similarity between two related virus strains that considers the presence and abundance of glycopeptide glycoforms. We demonstrate the strength of our approach by determining that there was a quantifiable difference in glycosylation at the protein level between wild-type IAV HA from A/Switzerland/9715293/2013 (SWZ13) and a mutant strain of SWZ13, even though no N-glycosylation sequons were changed. We determined site-specifically that WT and mutant HA have varying similarity at the glycosylation sites of the head domain, reflecting competing pressures to evade host immune response while retaining viral fitness. To our knowledge, our results are the first to quantify changes in glycosylation state that occur in related proteins of considerable glycan heterogeneity. Our results provide a method for understanding how changes in glycosylation state are correlated with variations in protein sequence, which is necessary for improving IAV vaccine strain selection. Understanding glycosylation will be especially important as we find new expression vectors for vaccine production, as glycosylation state depends greatly on the host species.

biochemistry↗