Previous Article | Next Article ![]()
Journal of Virology, February 1999, p. 1382-1391, Vol. 73, No. 2
Laboratory of Infectious Diseases, National
Institute of Allergy and Infectious Diseases, National Institutes
of Health, Bethesda, Maryland 20892
Received 27 May 1998/Accepted 5 November 1998
Guanylyltransferases are members of the nucleotidyltransferase
family and function in mRNA capping by transferring GMP to the
phosphate end of nascent RNAs. Although numerous guanylyltransferases have been identified, studies which define the nature of the
interaction between the capping enzymes of any origin and their RNA
substrates have been limited. Here, we have characterized the
RNA-binding activity of VP3, a minor protein component of the core of
rotavirions that has been proposed to function as the viral
guanylyltransferase and to direct the capping of the 11 transcripts
synthesized from the segmented double-stranded RNA (dsRNA) genome of
these viruses. Gel shift analysis performed with disrupted (open)
virion-derived cores and virus-specific RNA probes showed that VP3 has
affinity for single-stranded RNA (ssRNA) but not for dsRNA. While the
ssRNA-binding activity of VP3 was found to be sequence independent, the
protein does exhibit preferential affinity for uncapped over capped
RNA. Like the RNA-binding activity, RNA capping assays performed with open cores indicates that the guanylyltransferase activity of VP3 is
nonspecific and is able to cap RNAs initiating with a G or an A
residue. These data establish that all three rotavirus core proteins,
VP1, the RNA polymerase; VP2, the core capsid protein; and VP3, the
guanylyltransferase, have affinity for RNA but that only in the case of
the RNA polymerase is the affinity sequence specific.
0022-538X/99/$00.00+0
RNA-Binding and Capping Activities of Proteins
in Rotavirus Open Cores
*
Corresponding author. Mailing address: Laboratory of
Infectious Diseases, National Institute of Allergy and Infectious
Diseases, National Institutes of Health, 7 Center Dr., MSC 0720, Rm.
117, Bethesda, MD 20892. Phone: (301) 496-3372. Fax: (301) 496-8312. E-mail: JPATTON{at}atlas.niaid.nih.gov.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»