Key result
Deletion or mutation of the stem-loop II motif (s2m) prevented viral propagation in astrovirus VA1 and reduced titers in HAstV1, but had no effect on SARS-CoV-2 growth in vitro or in vivo.
Why the study?
The functional significance of the highly conserved stem-loop II motif RNA element present across divergent viral families was unknown.
The highly conserved s2m RNA element is essential for astrovirus replication but dispensable for SARS-CoV-2 in vitro and in vivo.
s2m inhibition may not affect SARS-CoV-2; leaves open virus-specific roles for this conserved element.
The stem-loop II motif (s2m) is an RNA element present in viruses from divergent viral families, including astroviruses and coronaviruses, but its functional significance is unknown. We created deletions or substitutions of the s2m in astrovirus VA1 (VA1), classic human astrovirus 1 (HAstV1) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For VA1, recombinant virus could not be rescued upon partial deletion of the s2m or substitutions of G-C base pairs. Compensatory substitutions that restored the G-C base-pair enabled recovery of VA1. For HAstV1, a partial deletion of the s2m resulted in decreased viral titers compared to wild-type virus, and reduced activity in a replicon system. In contrast, deletion or mutation of the SARS-CoV-2 s2m had no effect on the ability to rescue the virus, growth in vitro , or growth in Syrian hamsters. Our study demonstrates the importance of the s2m is virus-dependent.
No takes yet. Share an insight, caveat, or question.
Janowski et al. (2022) studied Viral infection (Astrovirus, SARS-CoV-2). s2m deletion or mutation vs. Wild-type virus was evaluated on Viral propagation and growth (in vitro and in vivo). Deletion or mutation of the stem-loop II motif (s2m) prevented viral propagation in astrovirus VA1 and reduced titers in HAstV1, but had no effect on SARS-CoV-2 growth in vitro or in vivo.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: