(A) Merbecovirus RBD phylogenetic tree based on amino acid sequences defining 6 clades. c/hMERS: camel/human MERS-CoV isolates. Each merbecovirus is listed along with its GenBank ID. The animal symbols represent the hosts in which viruses have been detected.
(B) Phylogenetic trees of bat (top) or non-bat (bottom) mammalian ACE2 orthologs based on amino acid sequences, with genera and orders indicated for the bat and non-bat mammalian species, respectively.
(C and D) Binding of the HKU5-19s RBD-hFc to and entry of HKU5-19s S VSV pseudovirus (pretreated with 100 μg/mL TPCK-treated trypsin) into HEK293T cells transiently transfected with the indicated bat (C) or non-bat (D) mammalian ACE2 orthologs. Abbr: abbreviations used for species names. Mean values are shown in (C) and (D) with n = 3 biological replicates.
(E and F) Propagation of pcVSV-HKU5-1 (E, left), pcVSV-HKU5-19s (E, right), and wild-type authentic HKU5-1 (F) in human Caco-2 cells (endogenously expressing hACE2) or Caco-2 cells with stable expression of either hACE2 or P.abr ACE2. The propagation of pcVSV-HKU5-1 was detected by the expression of the GFP reporter gene at the indicated hours post-infection (hpi), whereas authentic HKU5-1 was detected by immunofluorescence with an anti-HKU5 N antibody at 24 hpi. The trypsin concentration used is indicated. Exogenous ACE2 expression was confirmed by immunofluorescence using C-terminally fused FLAG tags. Scale bars: 200 μm in (E) and 100 μm in (F).
See also Figures S1, S2, and S3.
#Medsky🧪 #IDSky #immunosky #Publichealth Fascinating study & findings profoundly alter our understanding of coronavirus evolution, as several merbecovirus clades independently evolved #ACE2 utilization that pave the way for developing countermeasures against viruses poised for human emergence.