Previous Article | Next Article ![]()
Journal of Virology, April 2001, p. 3111-3120, Vol. 75, No. 7
Institute for Molecular Virology and
Department of Biochemistry, University of Wisconsin-Madison,
Madison, Wisconsin 53706
Received 28 June 1999/Accepted 4 January 2001
An alignment of cardiovirus sequences led to the prediction of
three conserved stem-loops in the 3' untranslated region (UTR) of
mengovirus. Deletions of each stem were engineered in mengovirus cDNAs
and also in mengovirus replicons, in which part of the viral capsid
sequences were replaced with the firefly luciferase gene. The effect of
deletion on RNA infectivity and plaque phenotype was evaluated after
transfection of viral transcripts into HeLa cells or by luciferase
assays of cellular extracts after transfection with RNA replicons. Stem
I (mengovirus bases 7666 to 7687) was found to be dispensable for viral
growth or exponential luciferase expression. Deletion of stem III
(bases 7711 to 7721) was lethal to the virus, and the replicons were
incapable of RNA synthesis. Deletion of stem II (
0022-538X/01/$04.00+0 DOI: 10.1128/JVI.75.7.3111-3120.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Phenotypic Characterization of Three
Phylogenetically Conserved Stem-Loop Motifs in the Mengovirus 3'
Untranslated Region
II; bases 7692 to
7705) produced an intermediate phenotype, in that replicons had
marginal RNA synthesis activity but transfection with genomic RNA
usually failed to produce plaques after normal incubation times (31 h,
37°C). In a few of the
II transfections, however, plaques were
observed after long incubation, especially if the cells received large
amounts of RNA (3 µg per 3 × 106 cells). Viruses
from two
II-derived plaques were isolated and amplified. Their RNAs
were converted into cDNA, sequenced, and mapped for genotype. Each
maintained the
II deletion and, in addition, had one or two
reversion mutations, which were characterized by reverse genetics as
responsible for the phenotypes. One reversion caused an amino acid
change in the polymerase (3Dpol), and the other was
localized to the 3' UTR, upstream of stem I.
*
Corresponding author. Mailing address: Department of
Biochemistry, 433 Babcock Dr., Madison, WI 53706. Phone: (608)
262-7519. Fax: (608) 262-6690. E-mail:
acpalmen{at}facstaff.wisc.edu.
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|