COVID-19 researchGene: POLR3A
May contribute to viral susceptibility in a non-Mendelian way
Created: 1 May 2020, 12:17 p.m. | Last Modified: 1 May 2020, 12:17 p.m.
Panel Version: 0.171
IUIS: categorised under the Predisposition to severe viral infection section. Inheritance: AD. Affects Leukocytes and other cells and causes impaired viral recognition and IFN induction in response to VZVor poly I:C. The associated features is severe VZV infection.
Created: 15 Apr 2020, 12:09 p.m. | Last Modified: 15 Apr 2020, 12:09 p.m.
Panel Version: 0.103
Mode of inheritance
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Defects in intrinsic and innate immunity; Predisposition to severe viral infection; RNA polymerase III deficiency
This gene is responsible for A subunit of Polymerase which senses DNA viruses especially AT-rich regions eg Varicella Zoster. SARS-CoV-2 is an RNA virus.
Inborn errors in RNA polymerase III underlie severe varicella zoster virus infections(PMID: 28783042)
We report 4 cases of acute severe VZV infection affecting the central nervous system or the lungs in unrelated, otherwise healthy children who are heterozygous for rare missense mutations in POLR3A (one patient), POLR3C (one patient), or both (two patients). POLR3A and POLR3C encode subunits of RNA polymerase III. Leukocytes from all 4 patients tested exhibited poor IFN induction in response to synthetic or VZV-derived DNA. Moreover, leukocytes from 3 of the patients displayed defective IFN production upon VZV infection and reduced control of VZV replication. These phenotypes were rescued by transduction with relevant WT alleles. This work demonstrates that monogenic or digenic POLR3A and POLR3C deficiencies confer increased susceptibility to severe VZV disease in otherwise healthy children, providing evidence for an essential role of a DNA sensor in human immunity
Different classes of PRRs are involved in recognition of virus infections, including membrane-associated TLRs; cytosolic retinoic acid–inducible gene 1–like (RIG-I–like) receptors, which sense RNA; and DNA sensors (24). Each of these classes of PRRs stimulates production of IFNs, which exhibit antiviral activity through their ability to induce IFN-stimulated genes (ISGs). With respect to DNA sensors, TLR9 detects unmethylated DNA, RNA polymerase III (POL III) recognizes AT-rich DNA, while gamma-interferon-inducible protein 16 (IFI16) and cyclic GMP-AMP synthase (cGAS) sense double-stranded DNA in a sequence-independent manner (25–29).
Mutations in RNA Polymerase III genes and defective DNA sensing in adults with varicella-zoster virus CNS infection
Recently, deficiency in the cytosolic DNA sensor RNA Polymerase III was described in children with severe primary varicella-zoster virus (VZV) infection in the CNS and lungs. In the present study we examined adult patients with VZV CNS infection caused by viral reactivation. By whole exome sequencing we identified mutations in POL III genes in two of eight patients. These mutations were located in the coding regions of the subunits POLR3A and POLR3E. In functional assays, we found impaired expression of antiviral and inflammatory cytokines in response to the POL III agonist Poly(dA:dT) as well as increased viral replication in patient cells compared to controls. Altogether, this study provides significant extension on the current knowledge on susceptibility to VZV infection by demonstrating mutations in POL III genes associated with impaired immunological sensing of AT-rich DNA in adult patients with VZV CNS infection.
Created: 10 Apr 2020, 12:31 p.m. | Last Modified: 10 Apr 2020, 12:32 p.m.
Panel Version: 0.81
Added POLR3A to panel based on presence on VCGS 'Susceptibility to Viral Infections' panel V0.22: https://panelapp.agha.umccr.org/panels/237/
Created: 9 Apr 2020, 4:16 p.m. | Last Modified: 9 Apr 2020, 4:18 p.m.
Panel Version: 0.76
Publications for gene: POLR3A were set to 29728610; 28783042
Source Expert Review Green was added to POLR3A. Source IUIS Classification December 2019 was added to POLR3A. Added phenotypes RNA polymerase III deficiency; Defects in intrinsic and innate immunity; Predisposition to severe viral infection for gene: POLR3A Rating Changed from Amber List (moderate evidence) to Green List (high evidence)
gene: POLR3A was added gene: POLR3A was added to Viral susceptibility. Sources: Victorian Clinical Genetics Services,Expert list,Expert Review Amber Mode of inheritance for gene: POLR3A was set to MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted Publications for gene: POLR3A were set to 29728610; 28783042 Phenotypes for gene: POLR3A were set to Severe VZV infection