Thread by @stevenemassey

Great critique by Billy of a preprint purporting to show a "FCS" in a novel coronavirus from Brazil

I would add that

1) no evidence is presented that the cleavage site is cleaved by furin.. 🧵

https://x.com/BillyBostickson/status/1983865782649155881

In addition, cleavage occurs after secretion into the culture medium, which seems inconsistent with furin as responsible for cleavage during infection

Whether it actually undergoes cleavage as part of its cell entry mechanism is unclear

2) The new CoV (BRZ CoV) is claimed as a beta-CoV. No whole genome tree is presented, to compare with the other CoV genus's

The RdRp tree shows its placement in the beta-CoVs is uncertain. Also that the lineage is not novel, as it is highly similar to 2 existing sequences

3) It is claimed that the cleavage site is at the S1/S2 junction. As noted by Billy this is incorrect, given that it is 200 amino acids away from the SARS2 FCS (which is at the S1/S2 junction)

This is confirmed by the larger size of BRZ CoV's cleaved spike

4) No genome sequence is provided, or alignments

The find has been hyped in the media, but the authors have not provided the relevant data that would allow scrutiny of the claims

Is this deliberate ? Maybe Proximal Eddie knows

Holmes has a cozy relationship with 'higher ups' in the British establishment

It may be no accident that the Daily Mail was chosen to publish a breathless article on the new coronavirus and its "FCS"

x.com/i/grok/share/r…

5) The claimed large size of the BRZ CoV spike (1479 aa compared to 1273 aa in SARS2) seems dubious. Take a look at the genome structure below, it shows that the spike gene overlaps ORF1b. Odd

All in all, little substance to support the claims

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