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Updated: Aug 5, 2025
10:50
Assessment of Immunologically Relevant Dynamic Tertiary Structural Features of the HIV-1 V3 Loop Crown R2 Sequence by ab initio Folding
Published on: September 15, 2010
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The highly conserved stem-loop II motif is dispensable for SARS-CoV-2
Hongbing Jiang1,2, Astha Joshi3, Tianyu Gan2
1School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, China.
Biorxiv : the Preprint Server for Biology
|March 30, 2023
Summary
The stem-loop II motif (s2m) in SARS-CoV-2 is not essential for viral replication. Deleting or mutating the s2m did not impact viral growth in vitro or in vivo, suggesting it is dispensable.
Area of Science:
- Virology
- RNA structure and function
- Molecular biology
Background:
- The stem-loop II motif (s2m) is an RNA structural element present in the 3' untranslated region (UTR) of SARS-CoV-2.
- The functional significance of the s2m motif, despite its discovery over 25 years ago, remains largely unknown in the context of SARS-CoV-2.
Approach:
- Engineered SARS-CoV-2 variants with deletions or mutations in the s2m motif using reverse genetics.
- Assessed viral replication and fitness in vitro (tissue culture) and in vivo (Syrian hamsters).
- Utilized SHAPE-MaP and DMS-MaPseq to compare the secondary structure of the 3' UTR in wild-type and modified viruses.
Key Points:
- Deletion or mutation of the s2m motif had no discernible effect on SARS-CoV-2 growth in vitro.
- Viral fitness and growth in Syrian hamsters were unaffected by s2m alterations.
- The s2m motif forms an independent structural element, and its absence does not disrupt the overall 3' UTR RNA structure.
Conclusions:
- The stem-loop II motif (s2m) is dispensable for SARS-CoV-2 replication and infectivity.
- The structural integrity of the 3' UTR is maintained even without the s2m element.
- This finding contributes to understanding the non-essential RNA elements in SARS-CoV-2, potentially impacting future therapeutic strategies.
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