In mammals, cyclic GMP-AMP (cGAMP) synthase (cGAS) produces the cyclic dinucleotide (CDN) 2'3'-cGAMP in response to cytosolic DNA and this triggers an antiviral immune response. cGAS belongs to a large family of cGAS/DncV-like nucleotidyltransferases, present in both prokaryotes1 and eukaryotes2-5. In bacteria, these enzymes synthesize a range of cyclic oligonucleotide and have recently emerged as important regulators of phage infections6-8. Here, we identify two novel cGAS-like receptors (cGLRs) in the insect Drosophila melanogaster. We show that cGLR1 and cGLR2 activate Sting and NF-κB dependent antiviral immunity in response to infection with RNA or DNA viruses. cGLR1 is activated by dsRNA to produce the novel CDN 3'2'-cGAMP whereas cGLR2 produces a combination of 2'3'-cGAMP and 3'2' cGAMP in response to a yet unidentified stimulus. Our data establish cGAS as the founding member of a family of receptors sensing different types of nucleic acids and triggering immunity through production of CDNs beyond 2'3'-cGAMP.      «

In mammals, cyclic GMP-AMP (cGAMP) synthase (cGAS) produces the cyclic dinucleotide (CDN) 2'3'-cGAMP in response to cytosolic DNA and this triggers an antiviral immune response. cGAS belongs to a large family of cGAS/DncV-like nucleotidyltransferases, present in both prokaryotes1 and eukaryotes2-5. In bacteria, these enzymes synthesize a range of cyclic oligonucleotide and have recently emerged as important regulators of phage infections6-8. Here, we identify two novel cGAS-like receptors (cGLRs...     »