Characterization of a unique group-specific protein (U122) of the severe acute respiratory syndrome coronavirus
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Date
2004
Journal Title
Journal ISSN
Volume Title
Publisher
American Society for Microbiology
Abstract
A novel coronavirus (CoV) has been identified as the etiological agent of severe acute respiratory syndrome
(SARS). The SARS-CoV genome encodes the characteristic essential CoV replication and structural proteins.
Additionally, the genome contains six group-specific open reading frames (ORFs) larger than 50 amino acids,
with no known homologues. As with the group-specific genes of the other CoVs, little is known about the
SARS-CoV group-specific genes. SARS-CoV ORF7a encodes a putative unique 122-amino-acid protein, designated
U122 in this study. The deduced sequence contains a probable cleaved signal sequence and a C-terminal
transmembrane helix, indicating that U122 is likely to be a type I membrane protein. The C-terminal tail also
contains a typical endoplasmic reticulum (ER) retrieval motif, KRKTE. U122 was expressed in SARS-CoVinfected
Vero E6 cells, as it could be detected by Western blot and immunofluorescence analyses. U122 is
localized to the perinuclear region of both SARS-CoV-infected and transfected cells and colocalized with ER
and intermediate compartment markers. Mutational analyses showed that both the signal peptide sequence
and ER retrieval motif were functional.
Description
Keywords
Severe acute respiratory syndrome (SARS), Novel coronavirus (CoV)
Citation
Fielding, B., et al. (2004). Characterization of a unique group-specific protein (U122) of the severe acute respiratory syndrome coronavirus. Journal of Virology, 78(14): 7311-7318