REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
Monoclonal anti-HA antibody produced in mouse	Sigma-Aldrich	Cat.#: H3663; RRID: AB_262051
Monoclonal anti-β-actin antibody produced in mouse	Sigma-Aldrich	Cat.#: A5441; RRID: AB_476744
Monoclonal anti-VSV-M (23H12) antibody	KeraFast	Cat.#: EB0011; RRID: AB_2734773
Monoclonal anti-mouse, peroxidase-coupled	Dianova	Cat.#: 115-035-003; RRID: AB_10015289
Anti-VSV-G antibody (I1, produced from CRL-2700 mouse hybridoma cells)	ATCC	Cat.# CRL-2700; RRID: CVCL_G654
Bacterial and Virus Strains
VSV∗ΔG-FLuc	Berger Rentsch and Zimmer, 2011	N/A
One Shot™ OmniMAX™ 2 T1R Chemically Competent E. coli	Thermo Fisher Scientific	Cat.#: C854003
Chemicals, Peptides, and Recombinant Proteins
Lipofectamine LTX with Plus Reagent	Thermo Fisher Scientific	Cat.#: 15338100
Furin inhibitor, decanoyl-RVKR-CMK	Tocris	Cat.#: 3501
May-Grünwald solution	Sigma-Aldrich	Cat.#: 63590
Giemsa solution	Sigma-Aldrich	Cat.#: GS500
Critical Commercial Assays
Beetle-Juice Kit	PJK	Cat.#: 102511
Experimental Models: Cell Lines
293T	DSMZ	Cat.#: ACC-635; RRID: CVCL_0063
Calu-3	Laboratory of Stephan Ludwig	ATCC Cat# HTB-55; RRID: CVCL_0609
Vero	Laboratory of Andrea Maisner	ATCC Cat# CRL-1586; RRID: CVCL_0574
Vero-TMPRSS2	Hoffmann et al., 2020	N/A
Oligonucleotides
SARS-S (BamHI) F CTTGGATCCGCCACCATGTTTATTTTC TTATTATTTC	Sigma-Aldrich	N/A
SARS-SΔ18 (XbaI) R CTTTCTAGACTACTTGCAGCAAGAA CCACAAGAGC	Sigma-Aldrich	N/A
SARS-SΔ18 (-)STOP (XbaI) R CTTTCTAGACTTGCAGCAAG AACCACAAGAGC	Sigma-Aldrich	N/A
SARS-2-S (BamHI) F GAATTCGGATCCGCCACCATGTTCGT GTTTCTGGTGCTGC	Sigma-Aldrich	N/A
SARS-2-SΔ18 (XbaI) R AAGGCCTCTAGACTACTTGCAGCA GCTGCCACAGC	Sigma-Aldrich	N/A
SARS-2-SΔ18 (-)STOP (XbaI) R AAGGCCTCTAGACTTGCA GCAGCTGCCACAGC	Sigma-Aldrich	N/A
SARS-S (SARS) F CAGACAAACAGCCCCAGACGGGCCAG AAGTACTAGCCAAAAATCTATTG	Sigma-Aldrich	N/A
SARS-S (SARS) R TCTGGCCCGTCTGGGGCTGTTTGTCT GTGTATGGTAACTAGCACAAATGC	Sigma-Aldrich	N/A
SARS-S (RaTG) F CAGACAAACAGCAGAAGTACTAGCCA AAAATC	Sigma-Aldrich	N/A
SARS-S (RaTG) R TCTGCTGTTTGTCTGTGTATGGTAACTA GCACAAATGC	Sigma-Aldrich	N/A
SARS-2-S (SARS) F GTTTCTTTATTACGTTCTGTGGCCAGC CAGAGCATC	Sigma-Aldrich	N/A
SARS-2-S (SARS) R ACGTAATAAAGAAACTGTCTGGTAGC TGGCACAGATG	Sigma-Aldrich	N/A
SARS-2-S (RaTG) F CAGACAAACAGCAGATCTGTGGCCAGC CAGAGCATC	Sigma-Aldrich	N/A
SARS-2-S (RaTG) R GCTGGCCACAGATCTGCTGTTTGTCTG TGTCTGGTAGC	Sigma-Aldrich	N/A
SARS-2-S (delta) F CAAACAGCCCCGCATCTGTGGCCAGCC AGAGCATC	Sigma-Aldrich	N/A
SARS-2-S (delta) R GCTGGCCACAGATGCGGGGCTGTTTGTC TGTGTCTGGTAGC	Sigma-Aldrich	N/A
SARS-2-S (opt) F CGAAGACGAAAAAGATCTGTGGCCAGCCA GAGCATC	Sigma-Aldrich	N/A
SARS-2-S (opt) R TCTTTTTCGTCTTCGGCTGTTTGTCTGTGT CTGG	Sigma-Aldrich	N/A
pCG1 Seq F CCTGGGCAACGTGCTGGT	Sigma-Aldrich	N/A
pCG1 Seq R GTCAGATGCTCAAGGGGCTTCA	Sigma-Aldrich	N/A
SARS-S 387F TGTTATACGAGCATGTAAC	Sigma-Aldrich	N/A
SARS-S 790F AAGCCAACTACATTTATGC	Sigma-Aldrich	N/A
SARS S 1194F TGATGTAAGACAAATAGCG	Sigma-Aldrich	N/A
SARS S 1575F TATTAAGAACCAGTGTGTC	Sigma-Aldrich	N/A
SARS S 1987F GTGCTAGTTACCATACAG	Sigma-Aldrich	N/A
SARS S 2391F CTAAAGCCAACTAAGAGG	Sigma-Aldrich	N/A
SARS S 2787F TCAACTGCATTGGGCAAG	Sigma-Aldrich	N/A
SARS-2-S 651F CAAGATCTACAGCAAGCACACC	Sigma-Aldrich	N/A
SARS-2-S 1380F GTCGGCGGCAACTACAATTAC	Sigma-Aldrich	N/A
SARS-2-S 1992F CTGTCTGATCGGAGCCGAGCAC	Sigma-Aldrich	N/A
SARS-2-S 2648F TGAGATGATCGCCCAGTACAC	Sigma-Aldrich	N/A
SARS-2-S 3286F GCCATCTGCCACGACGGCAAAG	Sigma-Aldrich	N/A
pCG1-V5 F TCCCTAACCCTCTCCTCGGTCTCGATTCTACGTG AAAGCTGATCTTTTTCCCTCTGCC	Sigma-Aldrich	N/A
pCG1-V5 R GACCGAGGAGAGGGTTAGGGATAGGCTTACCG CATGCCTGCAGGTTTAAACAGTCG	Sigma-Aldrich	N/A
pCG1-XhoI R CTCCTCGAGTTCATAAGAGAAGAGGG	Sigma-Aldrich	N/A
Recombinant DNA
Plasmid: pCG1-SARS-S	Hoffmann et al., 2013	N/A
Plasmid: pCG1-SARS-S-HA	Hoffmann et al., 2020	N/A
Plasmid: pCG1-SARS-2-S	Hoffmann et al., 2020	N/A
Plasmid: pCG1-SARS-2-S-HA	Hoffmann et al., 2020	N/A
Plasmid: pCG1-SARS-SΔ18	Hoffmann et al., 2013	N/A
Plasmid: pCG1-SARS-SΔ18-V5	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18-V5	This paper	N/A
Plasmid: pCG1-SARS-SΔ18 (SARS-2)	This paper	N/A
Plasmid: pCG1-SARS-SΔ18-V5 (SARS-2)	This paper	N/A
Plasmid: pCG1-SARS-SΔ18 (RaTG)	This paper	N/A
Plasmid: pCG1-SARS-SΔ18-V5 (RaTG)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18 (SARS)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18-V5 (SARS)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18 (RaTG)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18-V5 (RaTG)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18 (delta)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18-V5 (delta)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18 (opt)	This paper	N/A
Plasmid: pCG1-SARS-2-SΔ18-V5 (opt)	This paper	N/A
Plasmid: pCAGGS-MERS-S-V5	Gierer et al., 2013	N/A
Plasmid: pCAGGS-VSV-G	Brinkmann et al., 2017	N/A
Plasmid: pCAGGS-DsRed	Hoffmann et al., 2013	N/A
Plasmid: pCG1	Laboratory of Roberto Cattaneo	N/A
Plasmid: pCG1-V5	This paper	N/A
Software and Algorithms
Hidex Sense Microplate Reader Software	Hidex Deutschland Vertrieb GmbH	https://www.hidex.de/
ChemoStar Imager Software (version v.0.3.23)	Intas Science Imaging Instruments GmbH	https://www.intas.de/
ZEN imaging software	Carl Zeiss	https://www.zeiss.com/
Clustal Omega	European Molecular Biology Laboratory – European Bioinformatics Institute (EMBL-EBI)	https://www.ebi.ac.uk/Tools/msa/clustalo/; Madeira et al., 2019
Adobe Photoshop CS5 Extended (version 12.0 3 32)	Adobe	https://www.adobe.com/
GraphPad Prism (version 8.3.0(538))	GraphPad Software	https://www.graphpad.com/
YASARA (version 19.1.27)	YASARA Biosciences GmbH	http://www.yasara.org/; Krieger and Vriend, 2014
Microsoft Office Standard 2010 (version 14.0.7232.5000)	Microsoft Corporation	https://products.office.com/home
Other
Prefusion structure of SARS-CoV spike glycoprotein (5X5B)	Yuan et al., 2017	https://www.rcsb.org/structure/5X5B