RNA Virus-Induced Interferon and PARP Activation
trigger
RNA virus infection and interferon signaling induce noncanonical PARP enzymes, including PARP7/TIPARP, PARP10, PARP12, and PARP14 in coronavirus contexts. This creates an NAD-consuming antiviral enzyme state upstream of ADP-ribosylation-dependent host restriction.
Downstream
-
NAD-Dependent Antiviral ADP-Ribosylation
Induced PARP enzymes use NAD to write ADP-ribose marks on target proteins.
NAD-Dependent Antiviral ADP-Ribosylation
central effector
PARP enzymes transfer ADP-ribose from NAD onto target proteins as mono- or poly-ADP-ribose marks. In infected cells, noncanonical PARP activity can restrict viral replication, promote interferon output, and alter stress granule biology.
Used by disorders
COVID-19
as Host PARP9/DTX3L Antiviral ADP-Ribosylation
Downstream
-
PARG and Host De-ADP-Ribosylation Reset
Host hydrolases can reverse ADP-ribose marks and reset the PAR/MAR state.
-
Viral Macrodomain De-ADP-Ribosylation Countermeasure
Viral macrodomains oppose the same PARP-written antiviral marks.
PARG and Host De-ADP-Ribosylation Reset
amplifier
PARG removes poly-ADP-ribose polymers, while host macrodomains remove selected mono-ADP-ribose marks. This host erasure layer controls the duration and amplitude of ADP-ribosylation signals and is a natural comparison point for viral macrodomain activity.
Downstream
-
Viral Macrodomain De-ADP-Ribosylation Countermeasure
Viral macrodomains mimic or compete with host erasure logic to oppose antiviral PARP-written marks.
Viral Macrodomain De-ADP-Ribosylation Countermeasure
adaptive escape
Viral macrodomains bind and hydrolyze ADP-ribose modifications on host or viral proteins. By erasing PARP-written marks, they can blunt interferon production, disrupt antiviral stress granules, and remove restrictions on viral RNA synthesis or pathogenesis.
Used by disorders
COVID-19
as Nsp3 Macrodomain De-ADP-Ribosylation Countermeasure
Downstream
-
Enhanced Viral Replication and Pathogenesis
Viral de-ADP-ribosylation removes antiviral restrictions and can restore replication fitness or in vivo virulence.
Enhanced Viral Replication and Pathogenesis
consequence
When viral macrodomains successfully counter antiviral ADP-ribosylation, viruses can improve RNA synthesis, productive infection, tissue replication, or pathogenesis. Conversely, catalytic macrodomain defects attenuate replication or virulence and nominate macrodomains as antiviral targets.
Used by disorders
COVID-19
as Enhanced Viral Replication and Tissue Pathology