# Mechanisms of cell entry of Lymphocytic Choriomeningitis Virus.

> **NIH NIH F31** · HARVARD MEDICAL SCHOOL · 2020 · $39,035

## Abstract

Project Summary
Arenaviruses are zoonotic negative-sense RNA viruses closely associated with specific rodent hosts (1). Some
of these viruses, however, are known to cause human disease such as Lassa, Lymphocytic Choriomeningitis
Virus (LCMV), LuJo, Machupo, and Junín virus (6). The prototypic arenavirus that belongs to the Old World (OW)
clade, Lymphocytic Choriomeningitis Virus (LCMV), infects house mice (Mus musculus) and consequently has
a worldwide distribution (7, 8, 9, 10). While LCMV infection in humans is typically asymptomatic or associated
with mild illness, it can also cause abortions, congenital birth defects, and has been implicated in mortality of
transplant recipients (11, 12, 13, 14, 15). Moreover, LCMV infection of mice has proven to be an exceptionally
effective model system for the study of virus-host interactions, which has led to seminal discoveries in the fields
of microbiology and immunology (16, 17, 18). The glycoprotein complex (GPC) of arenaviruses mediates virus
entry into cells culminating in membrane fusion. The first arenavirus receptor to be discovered was alpha-
dystroglycan (α-DG) for the Old World viruses LASV and LCMV, and the Clade C New World arenaviruses
Olivero and Latino (19, 25). Previous work by us and others revealed that LASV entry was more complicated
than previously appreciated. Through the use of haploid genetic screens, the virus was found to rely on
Lysosomal Associated Membrane Protein 1 (LAMP1), in an α-DG-independent manner (28, 29). Lassa virus
attaches to glycosylated α-DG at neutral pH at the cell surface, and upon endocytic uptake and trafficking to
endosomal and lysosomal cell compartments, the GPC undergoes an acid pH-induced transition to engage
lysosomal membrane protein LAMP1 and drive membrane fusion (29). To date, the entry process LCMV remains
incompletely understood. LCMV has been reported to infect efficiently in the absence of its published receptor,
α-DG, nor is infection reliant upon LAMP1, suggesting that critical entry factor(s) remain unknown (20, 21, 29).
To identity unknown factors involved in LCMV entry, we did a preliminary genome-wide CRISPR-Cas9 screen
and identified CD164, a lysosomal protein, as the most significant hit. This preliminary data led us to hypothesize
that upon endocytic transport of LCMV to lysosomal compartments, LCMV GP engages CD164, which
then facilitates acid pH-dependent membrane fusion. Here, we propose to use genetic, cell biological,
biochemical, and structural studies to characterize the role of CD164 in LCMV entry. The first aim is to determine
the host genes required for cell entry of LCMV through the use of a CRISPR-Cas9 genome-wide loss-of-function
screen, followed by validation of significant hits through individual genetic knockouts and lentiviral addbacks.
The second aim is to probe the mechanism by which CD164 facilitates entry of LCMV by determining the domain
within CD164 and its necessary glycosylation through genetic manipulation of...

## Key facts

- **NIH application ID:** 10065966
- **Project number:** 1F31AI154700-01
- **Recipient organization:** HARVARD MEDICAL SCHOOL
- **Principal Investigator:** Carl Alexander Moon-Walker
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $39,035
- **Award type:** 1
- **Project period:** 2020-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10065966

## Citation

> US National Institutes of Health, RePORTER application 10065966, Mechanisms of cell entry of Lymphocytic Choriomeningitis Virus. (1F31AI154700-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10065966. Licensed CC0.

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