This Article Full Text Full Text (PDF) An author's correction has been published An author's correction has been published Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Cartwright, J. L. Articles by McLennan, A. G. Search for Related Content PubMed PubMed Citation Articles by Cartwright, J. L. Articles by McLennan, A. G.

The g5R (D250) Gene of African Swine Fever Virus Encodes a Nudix Hydrolase That Preferentially Degrades Diphosphoinositol Polyphosphates

School of Biological Sciences, University of Liverpool, Liverpool L69 7ZB,¹ School of Life Sciences, University of Dundee, Dundee DD1 5EH,² Institute for Animal Health, Pirbright GU24 0NF, United Kingdom,³ Department of Biophysics, Institute of Experimental Physics, University of Warsaw, 02-089 Warsaw, Poland⁴

Received 9 August 2001/ Accepted 5 September 2001

The African swine fever virus (ASFV) g5R gene encodes a protein containing a Nudix hydrolase motif which in terms of sequence appears most closely related to the mammalian diadenosine tetraphosphate (Ap₄A) hydrolases. However, purified recombinant g5R protein (g5Rp) showed a much wider range of nucleotide substrate specificity compared to eukaryotic Ap₄A hydrolases, having highest activity with GTP, followed by adenosine 5'-pentaphosphate (p₅A) and dGTP. Diadenosine and diguanosine nucleotides were substrates, but the enzyme showed no activity with cap analogues such as 7mGp₃A. In common with eukaryotic diadenosine hexaphosphate (Ap₆A) hydrolases, which prefer higher-order polyphosphates as substrates, g5Rp also hydrolyzes the diphosphoinositol polyphosphates PP-InsP₅ and [PP]₂-InsP₄. A comparison of the kinetics of substrate utilization showed that the k_cat/K_m ratio for PP-InsP₅ is 60-fold higher than that for GTP, which allows classification of g5R as a novel diphosphoinositol polyphosphate phosphohydrolase (DIPP). Unlike mammalian DIPP, g5Rp appeared to preferentially remove the 5-ß-phosphate from both PP-InsP₅ and [PP]₂-InsP₄. ASFV infection led to a reduction in the levels of PP-InsP₅, ATP and GTP by ca. 50% at late times postinfection. The measured intracellular concentrations of these compounds were comparable to the respective K_m values of g5Rp, suggesting that one or all of these may be substrates for g5Rp during ASFV infection. Transfection of ASFV-infected Vero cells with a plasmid encoding epitope-tagged g5Rp suggested localization of this protein in the rough endoplasmic reticulum. These results suggest a possible role for g5Rp in regulating a stage of viral morphogenesis involving diphosphoinositol polyphosphate-mediated membrane trafficking.

This article has been cited by other articles:

• Chapman, D. A. G., Tcherepanov, V., Upton, C., Dixon, L. K. (2008). Comparison of the genome sequences of non-pathogenic and pathogenic African swine fever virus isolates. J. Gen. Virol. 89: 397-408 [Abstract] [Full Text]  
• Parrish, S., Resch, W., Moss, B. (2007). Vaccinia virus D10 protein has mRNA decapping activity, providing a mechanism for control of host and viral gene expression. Proc. Natl. Acad. Sci. USA 104: 2139-2144 [Abstract] [Full Text]  
• Parrish, S., Moss, B. (2006). Characterization of a Vaccinia Virus Mutant with a Deletion of the D10R Gene Encoding a Putative Negative Regulator of Gene Expression. J. Virol. 80: 553-561 [Abstract] [Full Text]  
• Edelstein, P. H., Hu, B., Shinzato, T., Edelstein, M. A. C., Xu, W., Bessman, M. J. (2005). Legionella pneumophila NudA Is a Nudix Hydrolase and Virulence Factor. Infect. Immun. 73: 6567-6576 [Abstract] [Full Text]  
• Fisher, D. I., Safrany, S. T., Strike, P., McLennan, A. G., Cartwright, J. L. (2002). Nudix Hydrolases That Degrade Dinucleoside and Diphosphoinositol Polyphosphates Also Have 5-Phosphoribosyl 1-Pyrophosphate (PRPP) Pyrophosphatase Activity That Generates the Glycolytic Activator Ribose 1,5-Bisphosphate. J. Biol. Chem. 277: 47313-47317 [Abstract] [Full Text]  
• Hidaka, K., Caffrey, J. J., Hua, L., Zhang, T., Falck, J. R., Nickel, G. C., Carrel, L., Barnes, L. D., Shears, S. B. (2002). An Adjacent Pair of Human NUDT Genes on Chromosome X Are Preferentially Expressed in Testis and Encode Two New Isoforms of Diphosphoinositol Polyphosphate Phosphohydrolase. J. Biol. Chem. 277: 32730-32738 [Abstract] [Full Text]  
• Goatley, L. C., Twigg, S. R. F., Miskin, J. E., Monaghan, P., St-Arnaud, R., Smith, G. L., Dixon, L. K. (2002). The African Swine Fever Virus Protein j4R Binds to the Alpha Chain of Nascent Polypeptide-Associated Complex. J. Virol. 76: 9991-9999 [Abstract] [Full Text]