Journal
JOURNAL OF VIROLOGY
Volume 79, Issue 4, Pages 2287-2300Publisher
AMER SOC MICROBIOLOGY
DOI: 10.1128/JVI.79.4.2287-2300.2005
Keywords
-
Categories
Funding
- NCI NIH HHS [CA29303, R01 CA029303] Funding Source: Medline
- NIAID NIH HHS [AI26109, R01 AI026109, R37 AI026109] Funding Source: Medline
Ask authors/readers for more resources
The parvovirus minute virus of mice (MVM) packages predominantly negative-sense single strands, while its close relative LuIII encapsidates strands of both polarities with equal efficiency. Using genomic chimeras and mutagenesis, we show that the ability to package positive strands maps not, as originally postulated, to divergent untranslated regions downstream of the capsid gene but to the viral hairpins and predominantly to the nick site of 0611, the right-end replication origin. In MVM, the sequence of this site is 5'-CTATvTCA-3', while in LuIII a two-base insertion (underlined) changes it to 5'-CTATAT'vTCA-3'. Matched LuIII genomes differing only at this position (designated LuIII and LuDelta2) packaged 47 and <8% positive-sense strands, respectively. OriR sequences from these viruses were both able to support NS1-mediated nicking in vitro, but initiation efficiency was consistently two- to threefold higher for LuDelta2 derivatives, suggesting that LuIII's ability to package positive strands is determined by a suboptimal right-end origin rather than by strand-specific packaging sequences. These observations support a mathematical kinetic hairpin transfer model, previously described by Chen and colleagues (K. C. Chen, J. J. Tyson, M. Lederman, E. R. Stout, and R. C. Bates, I Mol. Biol. 208:283-296, 1989), that postulates that preferential excision of particular strands is solely responsible for packaging specificity. By analyzing replicative-form (RF) DNA generated in vivo during LuIII and LuDelta2 infections, we extend this model, showing that positive-sense strands do accumulate in LuDelta2 infections as part of duplex RE DNA, but these do not support packaging. However, replication is biphasic, so that accumulation of positive-sense strands is ultimately suppressed, probably because the onset of packaging removes newly displaced single strands from the replicating pool.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available