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

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

Ansari Mohammad Yunus; Singh Piyush Kumar; Rajagopalan Deepa; Shanmugam Purnima; Bellur Asutosh; Shaila Melkote Subbarao

Virus Genes

2019

2019-02

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.

Acid Anhydride Hydrolases/*metabolism; Animals; Baculoviridae/genetics; Cercopithecus aethiops; Cloning; Conventional mRNA capping; Enzyme Activation; Gene Expression; Genetic Vectors/genetics; Messenger/*genetics/*metabolism; Molecular; Morbillivirus; mRNA capping; Peste-des-petits-ruminants virus L protein; Peste-des-petits-ruminants virus/*physiology; Peste-des-Petits-Ruminants/*virology; PPRV; RNA; RNA Caps/*metabolism; RNA triphosphatase; Vero Cells; Viral Proteins/*metabolism

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

68–75

1

55

NEOMED College of Medicine

Department of Anatomy & Neurobiology