Investigating the role of LA crosse virus glycoprotein GN cytoplasmic tail in coordinating ribonucleoprotein assembly

The National Institute of Allergy and Infectious Diseases awarded $100,228 to Purdue University on December 8, 2026, under the Allergy and Infectious Diseases Research program (CFDA 93.855) to investigate the role of La Crosse virus glycoprotein GN cytoplasmic tail in coordinating ribonucleoprotein assembly.

La Crosse virus is the leading cause of pediatric encephalitis in the United States and can cause seizures and long-term neurological complications, yet no vaccines or antiviral therapies exist. The research addresses how the virus assembles new virions by examining how the glycoprotein GN cytoplasmic tail compensates for the absence of a matrix protein in bunyaviruses. The project will determine how conserved zinc finger motifs and two key residues (K222 and Y240) within the glycoprotein GN cytoplasmic tail mediate binding interactions with nucleoprotein and RNA-dependent RNA polymerase to promote ribonucleoprotein packaging and virion assembly. This knowledge gap must be closed to develop therapeutic strategies for vulnerable pediatric populations.

Work is performed at Purdue University in West Lafayette, Indiana. The award period runs from December 8, 2026, through August 16, 2028. This is a project grant, the assistance type used to support individual research projects.

Abstract

LA crosse virus (lacv), the leading cause of pediatric encephalitis in the united states, can lead to seizures and long-term neurological complications. Despite its clinical relevance, no vaccines or antiviral therapies exist, and there is limited understanding of its molecular biology, especially how IT assembles new virions. Addressing this knowledge GAP is critical for developing therapeutic strategies that could mitigate disease burden in vulnerable pediatric populations. Lacv is one of the bunyaviruses, and unlike other negative-sense RNA viruses, many bunyaviruses lack a matrix protein, a structural protein that mediates virion assembly by bridging the viral envelope and the ribonucleoprotein (RNP) complex. IT is hypothesized that the cytoplasmic tail of the viral glycoprotein GN (GN-CT) compensates for the absence of a matrix protein, but the specific mechanisms remain uncharacterized. Previous studies on several bunyaviruses have shown that the conserved cchc-type zinc finger (ZF) motifs within GN-CT mediate interactions with both the nucleoprotein (n) and the RNA-dependent RNA polymerase (rdrp) independently. Because interactions between GN-CT and n, as well as GN-CT and rdrp, remain poorly characterized in lacv, we performed preliminary docking simulations that identified two conserved residues, K222 and Y240, as potential key residues of these interactions in addition to the ZF motifs. Therefore, our central hypothesis is that the ZF motifs and conserved residues K222 and Y240 in GN-CT mediate interactions with n and rdrp independently to promote RNP packaging and virion assembly. We will test our hypothesis with two specific aims. For our first aim, we will determine how GN-CT ZFS, K222, and Y240 mediate binding to n protein using site-directed alanine mutations, glutathione-s-transferase (GST) pull-downs, circular dichroism (CD) spectroscopy, bioluminescence resonance energy transfer (bret), immunofluorescence, and virus-like particle (VLP) production assays. Our second aim will assess whether the ZFS and conserved residues regulate rdrp activity and localization to the golgi apparatus through surface plasmon resonance (SPR), in vitro rdrp assays, minigenome-based transcription assays, and immunofluorescence assays. By elucidating how the lacv virion assembles without a matrix protein, this research will reveal fundamental principles of viral assembly and identify new molecular targets for antiviral drug development. Overall, these findings will contribute to future therapeutic and vaccine strategies aimed at protecting children from life-threatening neurological disease caused by lacv.