Previous Article | Next Article ![]()
Journal of Virology, February 2000, p. 1321-1331, Vol. 74, No. 3
Virology Division, United States Army Medical
Research Institute of Infectious Diseases, Fort Detrick, Maryland 21702
Received 16 August 1999/Accepted 20 October 1999
Two independent, long-term infections were analyzed to determine
whether changes in viral replication could contribute to the
establishment and/or maintenance of persistent Seoul virus infections.
Infected cell cultures initially contained high levels of infectious
virus and intracellular viral RNA that peaked between approximately 7 to 16 days postinfection and then gradually declined until day 26. After day 26, the viral titers and the levels of the small (S), medium
(M), and large (L) viral RNAs varied cyclically until the end of the
studies. The changes in the concentrations of the RNAs and titer were
similar in pattern and appeared to result from changes in the
regulation of replication. Neither internal deletions nor an
accumulation of nucleotide changes were found in the RNAs. However,
fine mapping and sequence analysis revealed short deletions in some of
the RNAs in the conserved complementary terminal sequences believed to
contain the signals for initiation of replication and transcription.
Deletions at the 3' termini of S, M, and L virus-sense RNAs (vRNAs)
accumulated during the acute phase of infection just before the time
that the viral titer and the concentration of vRNAs and virus
complementary-sense RNAs (cRNAs) began to decline. The absence of
deletions at the 5' termini of the S, M, and L cRNAs suggests that the
3'-deleted vRNAs may not be replication competent. Thus, as the
percentage of 3'-deleted vRNAs increase in the population, they could
potentially compete with standard virus and downregulate viral
replication. Deletions at the 3' L cRNA and 5' L vRNA termini were also
observed, and the proportion of these deleted RNAs varied cyclically
during the infections. We propose a model in which terminal nucleotide deletions arise by nuclease activity of the viral polymerase. In
addition, we speculate that cleaved terminal fragments might be used as
primers during replication, resulting in the repair of some of the
deleted RNAs.
0022-538X/00/$04.00+0
Accumulation of Terminally Deleted RNAs May Play a
Role in Seoul Virus Persistence
*
Corresponding author. Mailing address: USAMRIID,
Department of Molecular Virology, Virology Division, 1301 Ditto Ave.,
Ft. Detrick, MD 21702-5011. Phone: (301) 619-4103. Fax: (301) 619-2439. E-mail: connie.schmaljohn{at}amedd.army.mil.
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»