The C962R ORF of African Swine Fever Strain Georgia Is Non-Essential and Not Required for Virulence in Swine.

Elizabeth Ramirez-Medina,Ayushi Rai,Sarah Pruitt,Ediane Silva,Douglas P Gladue,Manuel V Borca,James Zhu,Lauro Velazquez-Salinas,Elizabeth A Vuono

doi:10.3390/v12060676

Abstract

African swine fever virus (ASFV) is the causative agent of the African swine fever (ASF) epizootic currently affecting pigs throughout Eurasia, causing significant economic losses in the swine industry. The virus genome encodes for more than 160 genes, of which only a few have been studied in detail. Here we describe the previously uncharacterized ASFV open reading frame (ORF) C962R, a gene encoding for a putative NTPase. RNA transcription studies using infected swine macrophages demonstrate that the C962R gene is translated as a late virus protein. A recombinant ASFV lacking the C962R gene (ASFV-G-ΔC962R) demonstrates in vivo that the C962R gene is non-essential, since ASFV-G-ΔC962R has similar replication kinetics in primary swine macrophage cell cultures when compared to parental highly virulent field isolate Georgia2007 (ASFV-G). Experimental infection of domestic pigs with ASFV-G-ΔC962R produced a clinical disease similar to that caused by the parental ASFV-G, confirming that deletion of the C962R gene from the ASFV genome does not impact virulence.

Highlights

African swine fever virus (ASFV) is the causative agent of a very contagious and frequently lethal viral disease of swine, African swine fever (ASF)
We study the role of a previously uncharacterized ASFV gene, C962R, a highly conserved protein among ASFV isolates that is similar to the iridovirus primase family fused to
ASFV open reading frame (ORF) C962R is located on the positive strand of the ASFV Georgia2007 field isolate (ASFV-G)

Summary

Introduction

African swine fever virus (ASFV) is the causative agent of a very contagious and frequently lethal viral disease of swine, African swine fever (ASF). Viruses 2020, 12, 676 mainland Asia, the Philippines and most recently as far south as Timor-Leste and Papua New Guinea, just off the coast of Australia This continued spread of ASFV has the potential to cause a worldwide protein availability shortage and large economic losses in the swine industry [3]. There is no commercial vaccine for ASFV, and all experimental vaccines that show promise to the current circulating strain in Europe and Asia are live attenuated vaccines designed from the circulating isolate that originated in the Republic of Georgia, containing the deletion of one or more proteins from field isolates [4,5,6,7,8,9]. Experimental infection of domestic pigs with ASFV-G-∆C962R demonstrated that C962R is not required for virus virulence

Viruses and Cells

Construction of the Recombinant Viruses

Animal Experiments

Ethics Statement

Results and Discussion