The large protein 'L' of Peste-des-petits-ruminants virus exhibits RNA triphosphatase activity, the first enzyme in mRNA capping pathway.

Abstract

Peste-des-petits-ruminants is a highly contagious and fatal disease of goats and sheep caused by non-segmented, negative strand RNA virus belonging to the Morbillivirus genus-Peste-des-petits-ruminants virus (PPRV) which is evolutionarily closely related to Rinderpest virus (RPV). The large protein 'L' of the members of this genus is a multifunctional catalytic protein, which transcribes and replicates the viral genomic RNA as well as possesses mRNA capping, methylation and polyadenylation activities; however, the detailed mechanism of mRNA capping by PPRV L protein has not been studied. We have found earlier that the L protein of RPV has RNA triphosphatase (RTPase), guanylyltransferase (GTase) and methyltransferase activities, and unlike vesicular stomatitis virus (VSV), follows the conventional pathway of mRNA capping. In the present work, using a 5'-end labelled viral RNA as substrate, we demonstrate that PPRV L protein has RTPase activity when present in the ribonucleoprotein complex of purified virus as well as recombinant L-P complex expressed in insect cells. Further, a minimal domain in the C-terminal region (aa1640-1840) of the L protein has been expressed in E. coli and shown to exhibit RTPase activity. The RTPase activity of PPRV L protein is metal-dependent and functions with a divalent cation, either magnesium or manganese. In addition, RTPase associated nucleotide triphosphatase activity (NTPase) of PPRV L protein is also demonstrated. This work provides the first detailed study of RTPase activity and identifies the RTPase domain of PPRV L protein.

• Authors: Mohammad Yunus Ansari, Piyush Kumar Singh, Deepa Rajagopalan, Purnima Shanmugam, Asutosh Bellur, Melkote Subbarao Shaila
• Journal: Virus genes (Virus Genes) Vol. 55 Issue 1 Pg. 68-75 (Feb 2019) ISSN: 1572-994X [Electronic] United States
• PMID: 30511208 (Publication Type: Journal Article)

Chemical References

• RNA Caps
• RNA, Messenger
• Viral Proteins
• Acid Anhydride Hydrolases
• RNA triphosphatase

Topics

• Acid Anhydride Hydrolases (metabolism)
• Animals
• Baculoviridae (genetics)
• Chlorocebus aethiops
• Cloning, Molecular
• Enzyme Activation
• Gene Expression
• Genetic Vectors (genetics)
• Peste-des-Petits-Ruminants (virology)
• Peste-des-petits-ruminants virus (physiology)
• RNA Caps (metabolism)
• RNA, Messenger (genetics, metabolism)
• Vero Cells
• Viral Proteins (metabolism)