期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：32
DOI：10.1073/pnas.2205690119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
This study demonstrates that in addition to the furin cleavage site (FCS), both the length/composition of the exterior loop and glycosylation of the QTQTN motif are necessary for efficient SARS-CoV-2 infection and pathogenesis. Disruption of any of these three elements reduces SARS-CoV-2 replication, alters entry pathway utilization, and attenuates in vivo disease. Together, the work highlights the complexity of spike activation beyond just the presence of an FCS.
The furin cleavage site (FCS), an unusual feature in the SARS-CoV-2 spike protein, has been spotlighted as a factor key to facilitating infection and pathogenesis by increasing spike processing. Similarly, the QTQTN motif directly upstream of the FCS is also an unusual feature for group 2B coronaviruses (CoVs). The QTQTN deletion has consistently been observed in in vitro cultured virus stocks and some clinical isolates. To determine whether the QTQTN motif is critical to SARS-CoV-2 replication and pathogenesis, we generated a mutant deleting the QTQTN motif (ΔQTQTN). Here, we report that the QTQTN deletion attenuates viral replication in respiratory cells in vitro and attenuates disease in vivo. The deletion results in a shortened, more rigid peptide loop that contains the FCS and is less accessible to host proteases, such as TMPRSS2. Thus, the deletion reduced the efficiency of spike processing and attenuates SARS-CoV-2 infection. Importantly, the QTQTN motif also contains residues that are glycosylated, and disruption of its glycosylation also attenuates virus replication in a TMPRSS2-dependent manner. Together, our results reveal that three aspects of the S1/S2 cleavage site—the FCS, loop length, and glycosylation—are required for efficient SARS-CoV-2 replication and pathogenesis.
关键词：enSARS-CoV-2spikeglycosylationQTQTNfurin cleavage site
