Details

Autor(en) / Beteiligte

• Escalera, Alba
• Laporte, Manon
• Turner, Sam
• Karakus, Umut
• Gonzalez-Reiche, Ana S
• van de Guchte, Adriana
• Farrugia, Keith
• Khalil, Zain
• van Bakel, Harm
• Smith, Derek
• García-Sastre, Adolfo
• Aydillo, Teresa

Titel

The impact of S2 mutations on Omicron SARS-CoV-2 cell surface expression and fusogenicity

Ist Teil von

• Emerging microbes & infections, 2024-12, Vol.13 (1), p.2297553-2297553

Ort / Verlag

United States: Taylor & Francis

Erscheinungsjahr

2024

Quelle

MEDLINE

Beschreibungen/Notizen

• SARS-CoV-2 Omicron subvariants are still emerging and spreading worldwide. These variants contain a high number of polymorphisms in the spike (S) glycoprotein that could potentially impact their pathogenicity and transmission. We have previously shown that the S:655Y and P681H mutations enhance S protein cleavage and syncytia formation. Interestingly, these polymorphisms are present in Omicron S protein. Here, we characterized the cleavage efficiency and fusogenicity of the S protein of different Omicron sublineages. Our results showed that Omicron BA.1 subvariant is efficiently cleaved but it is poorly fusogenic compared to previous SARS-CoV-2 strains. To understand the basis of this phenotype, we generated chimeric S protein using combinations of the S1 and S2 domains from WA1, Delta and Omicron BA.1 variants. We found that the S2 domain of Omicron BA.1 hindered efficient cell-cell fusion. Interestingly, this domain only contains six unique polymorphisms never detected before in ancestral SARS-CoV-2 variants. WA1 S proteins containing the six individuals S2 Omicron mutations were assessed for their fusogenicity and S surface expression after transfection in cells. Results showed that the S:N856K and N969K substitutions decreased syncytia formation and impacted S protein cell surface levels. However, we observed that "first-generation" Omicron sublineages that emerged subsequently, had convergently evolved to an enhanced fusogenic activity and S expression on the surface of infected cells while "second-generation" Omicron variants have highly diverged and showed lineage-specific fusogenic properties. Importantly, our findings could have potential implications in the improvement and redesign of COVID-19 vaccines.