KEY RESOURCES TABLE

REAGENT or RESOURCE	SOURCE	IDENTIFIER
Antibodies
InVivoMAb anti-mouse CD8β (Lyt 3.2)	BioXcell	Cat# BE0223
InVivoMAb anti-mouse PDL1 (10F.9G2)	BioXcell	Cat# BE0101
InVivoMAb anti-mouse CTLA4 (9D9)	BioXcell	Cat# BP0164
InVivo Plus anti-mouse IFNAR1 (MAR1-5A3)	BioXcell	Cat# BP0241
APC anti-mouse CD8a Antibody	BioLegend	Cat# 100712
PE anti-mouse CD3 Antibody	BioLegend	Cat# 100206
Anti-FcgIII/II receptor (clone 2.4G2)	BD Biosciences	Cat# 553141
PE anti-mouse H-2Kb bound to SIINFEKL Antibody	BD Biosciences	Cat# 141604
STING (D2P2F) Rabbit mAb	Cell Signaling Technology	Cat# 13647S
cGAS (D3O8O) Rabbit mA	Cell Signaling Technology	Cat# 31659S
Purified Mouse Anti-Human MLH-1	BD Biosciences	Cat# 550838
Phospho-Stat1 (Tyr701) (58D6) Rabbit mAb	Cell signaling technology	Cat# 9167
Alexa Fluor® 647 Annexin V	Biolegend	Cat# 640911
FITC anti-human CD8 Antibody	Biolegend	Cat# 344703
Brilliant Violet 421™ anti-human CD45 Antibody	Biolegend	Cat# 368521
Propidium Iodide Solution	Biolegend	Cat# 421301
PerCP/Cyanine5.5 anti-human CD4 Antibody	Biolegend	Cat# 317427
APC/Cyanine7 anti-mouse CD45 Antibody	Biolegend	Cat# 103116
atezolizumab	pharmacy	N/A
ipilimumab	pharmacy	N/A
Tubulin Antibody (B-5-1-2)	Santa Cruz Biotechnology	Cat# sc-23948
Chemicals, Peptides, and Recombinant Proteins
Recombinant Mouse FLT3L	BioLegend	Cat# 576306
Ovalbumin	Sigma- Aldrich	Cat# A2512
OVA257-264 (SIINFEKL)	Invivogen	Cat# vac-sin
SIYRYYGL (SIY) peptide	Sigma- Aldrich	N/A
Critical Commercial Assays
CFSE Cell Division Tracker Kit	BioLegend	Cat# 423801
Mouse IFN Beta ELISA Kit	PBL Assay Science	Cat# 42410-2
BD Cytometric Bead Array (CBA) Mouse Inflammation Kit	BD Biosciences	Cat# 552364
BD Mouse IFN-g ELISPOT Sets	BD Biosciences	Cat# 551083
SsoAdvanced Uni SYBR Grn Supmix	Bio-Rad	Cat# 1725272
EasySep™ Mouse CD11c Positive Selection Kit II	STEMCELL	Cat# 18780
EasySep Mouse CD8+ T Cell Isolation Kit	STEMCELL	Cat# 19853
Pico488 dsDNA quantification reagent	Lumiprobe life science solutions	Cat# 42010
ProlongTM Diamond Antifade Mountant with DAPI	Thermo Fisher Scientific	Cat# 36962
Cell Counting Kit-8	Fisher	Cat# 50-190-5565
Experimental Models: Cell Lines
4T1	ATCC	Cat# HTB-177™
4T1-HA	THIS PAPER	N/A
B16-OVA	THIS PAPER	N/A
TC-1	ATCC	Cat# CRL-2785™
TC1-OTI	this manuscript	N/A
MC38-OVA	THIS PAPER	N/A
H460	ATCC	Cat# HTB-177™
SW620	ATCC	Cat# CCL-227™
MCF7	ATCC	Cat# HTB-22™
HCT116	ATCC	ATCC® CCL-247™
4T1-Mlh1−/−	this manuscript	N/A
B16-OVA-Mlh1−/−	this manuscript	N/A
MC38-OVA-Mlh1−/−	this manuscript	N/A
TC1-Mlh1−/−	this manuscript	N/A
4T1-Mlh1−/−-Sting−/−	this manuscript	N/A
4T1-Mlh1−/−-cGAS−/−	this manuscript	N/A
B16-OVA-Mlh1−/−-Sting−/−	this manuscript	N/A
SW620-MLH1−/−	this manuscript	N/A
H460-MLH1−/−	this manuscript	N/A
MCF7-MLH1−/−	this manuscript	N/A
4T1-HA	this manuscript	N/A
HCT116+cGAS	this manuscript	N/A
HCT116+MLH1	this manuscript	N/A
4T1-Mlh1−/−+MLH1-mRFP	this manuscript	N/A
TC1-Mlh1−/−+MLH1	this manuscript	N/A
4T1-Mlh1−/−-HA	this manuscript	N/A
4T1-Mlh1−/−+mRFP	this manuscript	N/A
Experimental Models: Organisms/Strains
BALB/c	UTSW breeding Core	N/A
C57BL/6	UTSW breeding Core	N/A
C.129S7(B6)-Rag1tm1Mom/J	Jackson Laboratory	Cat# 003145
B6(Cg)-Ifnar1tm1.2Ees/J	Jackson Laboratory	Cat# 028256
B6(Cg)-Tmem173tm1.2Camb/J	Jackson Laboratory	Cat# 025805
B6.129S(C)-Batf3tm1Kmm/J	Jackson Laboratory	Cat# 013755
C.129S-Batf3tm1Kmm/J	Jackson Laboratory	Cat# 013756
C57BL/6-Tg(TcraTcrb)1100Mjb/J	Jackson Laboratory	Cat# 003831
B6.129P2(SJL)-Myd88tm1.1Defr/J	Jackson Laboratory	Cat# 009088
B6.129S6-Rag2tm1Fwa Tg(TcraTcrb)1100Mjb	Jackson Laboratory	Cat# 2334
B6.129S6-Rag2tm1Fwa Tg(TcraTcrb)1100Mjb	Taconic Farms	Cat# 2334
C.129S6(B6)-Rag2tm1Fwa N12	Taconic Farms	Cat# 601
Clone4-Tg	a gift from David Farrar	n/a
Oligonucleotides
Actb (cytosolic DNA in mouse cells)	Forward CCAGGTAAGTGACCTGTTAC Reverse GGGGTACTTCAGGGTCAGGA	N/A
Gapdh (cytosolic DNA in mouse cells)	Forward CAACTGCTTAGCCCCCCTGG Reverse GCAGGGTAAGATAAGAAATG	N/A
Actb (qPCR in mouse cells)	Forward AGATCAAGATCATTGCTCCTCCT Reverse ACGCAGCTCAGTAACAGTCC	N/A
Mx2 (qPCR in mouse cells)	Forward ACCAGGCTCCGAAAAGAGTTC Reverse AGCTCGTACAATTTCAGTGACC	N/A
Isg15 (qPCR in mouse cells)	Forward GAGCTAGAGCCTGCAGCAAT Reverse TCACGGACACCAGGAAATCG	N/A
Irf7 (qPCR in mouse cells)	Forward TTGGGCAAGACTTGTCAGCA Reverse ATACCCATGGCTCCAGCTTC	N/A
Pdl1 (qPCR in mouse cells)	Forward TGATCATCCCAGAACTGCCTG Reverse AGAAGAGGAGGACCGTGGAC	N/A
Mlh1 (gRNA-1 for mouse gene)	Forward CACCGCAACCAGGGCACCCTGATCA Reverse AAACTGATCAGGGTGCCCTGGTTGC	N/A
Mlh1 (gRNA-2 for mouse gene)	Forward CACCGCTAATTCAGATCCAAGACAA Reverse AAACTTGTCTTGGATCTGAATTAGC	N/A
Sting (gRNA for mouse gene)	Forward CACCGTGCCCAGGGCGTCTCCTTG Reverse AAACCAAGGAGACGCCCTGGGCAC	N/A
cGAS (gRNA for mouse gene)	Forward CACCGCGCAAAGGGGGGCTCGATCG Reverse AAACCGATCGAGCCCCCCTTTGCGC	N/A
MLH1 (gRNA for human gene)	Forward CACCGTGATAGCATTAGCTGGCCGC Reverse AAACCGCGGCCAGCTAATGCTATCAC	N/A
ACTB (cytosolic DNA in human cells)	Forward TACAATGAGCTGCGTGTGGC Reverse GCGGCCACCAGAAGAGGTAG	N/A
GAPDH (cytosolic DNA in human cells)	Forward AGCCACATCGCTCAGACAC Reverse GCCCAATACGACCAAATCC	N/A
GAPDH (qPCR in human cells)	Forward AGCCACATCGCTCAGACAC Reverse GCCCAATACGACCAAATCC	N/A
ISG15 (qPCR in human cells)	Forward GCGAACTCATCTTTGCCAGTA Reverse CCAGCATCTTCACCGTCAG	N/A
MX1 (qPCR in human cells)	Forward TTCAGCACCTGATGGCCTA Reverse AAAGGGATGTGGCTGGAGAT	N/A
Recombinant DNA
Mlh1 (NM_026810) Mouse Tagged ORF Clone	Origene	Cat# MR210511
human cGAS cDNA	THIS PAPER	N/A
human MLH1 cDNA	THIS PAPER	N/A
Software and Algorithms
GraphPad Prism 8	GraphPad Software, Inc.	https://www.graphpad.com/scientific-software/prism/
Image Lab Software	Bio-Rad	https://www.bio-rad.com/en-us/product/image-lab-software?ID=KRE6P5E8Z
CytExpert 2.3	Beckman Coulter, Inc	https://www.beckman.com/flow-cytometry/instruments/cytoflex/software
FlowJo	Tree Star Inc.	https://www.flowjo.com/solutions/flowjo/downloads
Other
TRIZOL REAGENT	Thermo-Invitrogen	Cat# 15596018
ProtoScript® II Reverse Transcriptase	NEB	Cat# M0368L
Dulbecco’s Modified Eagle’s Medium	Sigma- Aldrich	Cat# D6429