Stewart, B. M. | Search bioRxiv

bioRxiv2024

Membrane asymmetry facilitates murine norovirus entry and persistent enteric infection

Norovirus, the leading cause of gastroenteritis worldwide, is a non-enveloped virus whose tropism is determined in part by the expression patterns of entry receptors. However, the contribution of cellular lipids to viral entry is not well understood. Here, we determined that the asymmetrical distribution of lipids within membrane bilayers is required for murine norovirus (MNV) replication. Specifically, TMEM30a, an essential subunit of lipid flippases, is required for MNV replication in vitro. Disruption of TMEM30a in mouse intestinal epithelial cells prevents persistent, enteric infection by MNV in vivo. Mechanistically, TMEM30a facilitates MNV binding and entry. Surprisingly, exoplasmic phosphatidylserine (PS), a typical marker of dying cells, does not inhibit MNV infection. Rather, TMEM30a maintains a lipid ordered state that impacts membrane fluidity that is necessary for the low affinity, high avidity binding of MNV to cells. Our data provides a new role for lipid asymmetry in promoting non-enveloped virus infection in vitro and norovirus persistence in vivo.

microbiology↗

bioRxiv2019

Detection of Reticuloendotheliosis Virus in Brazil

Reticuloendotheliosis retroviruses (REV) are known to cause immunosuppressive and oncogenic disease that affects numerous avian species. REV is present worldwide and recently has been reported in South America with cases of infected commercial flocks in Argentina. We surveyed for the presence of REV in birds from a state in the northern region of Brazil using real-time PCR. We report the first cases of REV in Brazil, detected in Muscovy ducks (Cairina moschata), wild turkeys (Meleagris gallopavo), and chickens (Gallus gallus) at a relatively high prevalence rate (16,8%). Phylogenetic analysis indicated a close relationship of this strain to variants in the United States. This study provides evidence of REV in the Amazon biome and provides a baseline for future surveillance of the virus in the region and throughout Brazil.

ecology↗