. Author manuscript; available in PMC: 2021 Jun 1.

Published in final edited form as: Nat Protoc. 2020 Oct 26;15(12):3777–3787. doi: 10.1038/s41596-020-00403-2

Table 1.

GEMM designs suitable for COVID-19 and SARS-CoV-2 research

Model #	Name	Locus/promoter	Gene to express	Expression	Additional features
*Category 1: Knocking-in expression cassettes or point mutations into endogenous mouse Ace2* loci**
1	B6.mAce2^KO-hACE2^KI	mAce2/ mAce2	hACE2	Constitutive	mAce2 gene is inactivated
2	B6.mAce2^KO-hACE2-P2A-EGFP^KI	mAce2/ mAce2	hACE2-P2A-EGFP	Constitutive	mAce2 gene is inactivated, includes a reporter
3	NSG.mAce2^KO-hACE2^KI	mAce2/ mAce2	hACE2	Constitutive	mAce2 gene is inactivated; immunocompromised mouse strain background, useful for studies involving interaction of human immune system
S4	NSG.mAce2^KO-hACE2-P2A-EGFP^KI	mAce2/ mAce2	hACE2-P2A-EGFP	Constitutive	mAce2 gene is inactivated, includes a reporter; immunocompromised mouse strain background, useful for studies involving interaction of human immune system
5	BALB/c.mAce2^KO-hACE2^KI	mAce2/ mAce2	hACE2	Constitutive	mAce2 gene is inactivated; mouse strain background commonly used for SARS and MERS virus research
6	BALB/c.mAce2^KO-hACE2-P2A-EGFP^KI	mAce2/ mAce2	hACE2-P2A-EGFP	Constitutive	mAce2 gene is inactivated, includes a reporter; mouse strain background commonly used for SARS and MERS virus research
7	B6.mAce2^{KI−31K,82M,353K}	mAce2/ mAce2	Partially humanized mAce2	Constitutive	Enables mACE2 to bind to the SARS-Co-V2 spike protein
8	NSG.mAce2^{KI−31K,82M,353K}	mAce2/ mAce2	Partially humanized mAce2	Constitutive	Enables mACE2 to bind to the SARS-Co-V2 spike protein; immunocompromised mouse strain background, useful for studies involving interaction of human immune system
9	BALB/c.mAce2^{KI−31K,82M,353K}	mAce2/ mAce2	Partially humanized mAce2	Constitutive	Enables mACE2 to bind to the SARS-Co-V2 spike protein; mouse strain background commonly used for SARS and MERS virus research
10	B6.mAce2^KO-hACE2-P2A-hTMPRSS2^KI	mAce2/ mAce2	hACE2, hTMPRSS2	Constitutive	mAce2 gene is inactivated; hTMPRSS2 fused to hACE2 via a self-cleavable P2A peptide
11	NSG.mAce2^KO-hACE2-P2A-hTMPRSS2^KI	mAce2/ mAce2	hACE2, hTMPRSS2	Constitutive	mAce2 gene is inactivated; immunocompromised mouse strain background, useful for studies involving interaction of human immune system; hTMPRSS2 fused to hACE2 via a self-cleavable P2A peptide
12	BALB/c.mAce2^KO-hACE2-P2A-hTMPRSS2^KI	mAce2/ mAce2	hACE2, hTMPRSS2	Constitutive	mAce2 gene is inactivated; mouse strain background commonly used for SARS and MERS virus research; hTMPRSS2 fused to hACE2 via a self-cleavable P2A peptide
13	B6.mAce2^KO-hACE2-IRES-hTMPRSS2^KI	mAce2/ mAce2	hACE2, hTMPRSS2	Constitutive	mAce2 gene is inactivated; hTMPRSS2 expressed as a separate polypeptide via an IRES
14	NSG.mAce2^KO-hACE2-IRES-hTMPRSS2^KI	mAce2/ mAce2	hACE2, hTMPRSS2	Constitutive	mAce2 gene is inactivated; immunocompromised mouse strain background, useful for studies involving interaction of human immune system; hTMPRSS2 expressed as a separate polypeptide via an IRES
15	BALB/c.mAce2^KO-hACE2-IRES-hTMPRSS2^KI	mAce2/ mAce2	hACE2, hTMPRSS2	Constitutive	mAce2 gene is inactivated; mouse strain background commonly used for SARS and MERS virus research; hTMPRSS2 expressed as a separate polypeptide via an IRES
Category 2: Knocking-in CRE-activatable or tetracycline-inducible expression cassettes into safe-harbor loci by re-engineering existing reporter or inducer mouse lines
16	ROSA26^{(ACTB-Lox-hACE2-P2A-tdT-Lox-EGFP)}	ROSA26/pCAG	hACE2	Constitutive	Constitutive expression of hACE2 with reporter capability
17	ROSA26^{(ACTB-Lox-hACE2-IRES-tdT-Lox-EGFP)}	ROSA26/pCAG	hACE2	Constitutive	Constitutive expression of hACE2 with reporter capability
18	ROSA26^{(ACTB-Lox-tdT-Lox-hACE2-P2A-EGFP)}	ROSA26/pCAG	hACE2	Tissue-specific	CRE-activatable expression of hACE2 with reporter capability.
19	ROSA26^{(ACTB-Lox-tdT-Lox-hACE2-IRES-EGFP)}	ROSA26/pCAG	hACE2	Tissue-specific	CRE-activatable expression of hACE2 with reporter capability.
20	Ai63-TIGRE-TRE-hACE2-P2A-tdT	TIGRE/ TRE	hACE2	Tetracyclin-inducible	Tetracycline inducible expression of hACE2 with reporter capability
21	Ai63-TIGRE-TRE-hACE2-IRES-tdT	TIGRE/ TRE	hACE2	Tetracyclin-inducible	Tetracycline inducible expression of hACE2 with reporter capability
*Category 3: Knocking-in CRE-activatable cassettes into mouse Ace2* locus**
22	B6.mAce2^cKO-hACE2^cKI	mAce2/ mAce2	hACE2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated allowing expression of hACE2
23	NSG.mAce2^cKO-hACE2^cKI	mAce2/ mAce2	hACE2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated allowing expression of hACE2; immunocompromised mouse strain background, useful for studies involving interaction of human immune system
24	BALB/c.mAce2^cKO-hACE2^cKI	mAce2/ mAce2	hACE2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2; mouse strain background commonly used for SARS and MERS virus research
25	B6.mAce2^cKO-hACE2-P2A-hTMPRSS2^cKI	mAce2/ mAce2	hACE2, hTMPRSS2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2 and hTMPRSS2; hTMPRSS2 fused to hACE2 via a self-cleavable P2A peptide
26	NSG.mAce2^cKO-hACE2-P2A-hTMPRSS2^cKI	mAce2/ mAce2	hACE2, hTMPRSS2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2 and hTMPRSS2; immunocompromised mouse strain background, useful for studies involving interaction of human immune system; hTMPRSS2 fused to hACE2 via a self-cleavable P2A peptide, immunocompromised mouse strain background
27	BALB/c.mAce2^cKO-hACE2-P2A-hTMPRSS2^cKI	mAce2/ mAce2	hACE2, hTMPRSS2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2 and hTMPRSS2; mouse strain background commonly used for SARS and MERS virus research; hTMPRSS2 fused to hACE2 via a self-cleavable P2A peptide
28	B6.mAce2^cKO-hACE2-IRES-hTMPRSS2^cKI	mAce2/ mAce2	hACE2, hTMPRSS2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2 and hTMPRSS2; hTMPRSS2 expressed as a separate polypeptide via an IRES
29	NSG.mAce2^cKO-hACE2-IRES-hTMPRSS2^cKI	mAce2/ mAce2	hACE2, hTMPRSS2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2 and hTMPRSS2; immunocompromised mouse strain background, useful for studies involving interaction of human immune system; hTMPRSS2 expressed as a separate polypeptide via an IRES
30	BALB/c.mAce2^cKO-hACE2-IRES-hTMPRSS2^cKI	mAce2/ mAce2	hACE2, hTMPRSS2	Tissue-specific expression of hACE2 at physiological levels	mAce2 gene is conditionally inactivated, allowing expression of hACE2 and hTMPRSS2; mouse strain background commonly used for SARS and MERS virus research; hTMPRSS2 expressed as a separate polypeptide via an IRES