Previous Article | Next Article ![]()
Journal of Virology, February 2001, p. 1656-1663, Vol. 75, No. 4
Laboratory of Viral Diseases, National
Institute of Allergy and Infectious Diseases, National Institutes of
Health, Bethesda, Maryland 20892
Received 4 October 2000/Accepted 15 November 2000
Previous analyses of randomly generated, temperature-sensitive
vaccinia virus mutants led to the mapping of DNA synthesis negative
complementation groups to the B1R, D4R, D5R, and E9L genes. Evidence
from the yeast two-hybrid system that the D4R and D5R proteins can
interact with the A20R protein suggested that A20R was also involved in
DNA replication. We found that the A20R gene was transcribed early
after infection, consistent with such a role. To investigate the
function of the A20R protein, targeted mutations were made by
substituting alanines for charged amino acids occurring in 11 different
clusters. Four mutants were not isolated, suggesting that they were
lethal, two mutants exhibited no temperature sensitivity, two mutants
exhibited partial temperature sensitivity, and two mutants formed no
plaques or infectious virus at 39°C. The two mutants with stringent
phenotypes were further characterized. Temperature shift-up experiments
indicated that the crucial period was between 6 and 12 h after
infection, making it unlikely that the defect was in virus entry, early
gene expression, or a late stage of virus assembly. Similar patterns of
metabolically labeled viral early proteins were detected at permissive
and nonpermissive temperatures, but one mutant showed an absence of
late proteins under the latter conditions. Moreover, no viral DNA
synthesis was detected when cells were infected with either stringent
mutant at 39°C. The previous yeast two-hybrid analysis together with the present characterization of A20R temperature-sensitive mutants suggested that the A20R, D4R, and D5R proteins are components of a
multiprotein DNA replication complex.
0022-538X/01/$04.00+0 DOI: 10.1128/JVI.75.4.1656-1663.2001
Role of Vaccinia Virus A20R Protein in DNA
Replication: Construction and Characterization of
Temperature-Sensitive Mutants
*
Corresponding author. Mailing address: Laboratory of
Viral Diseases, National Institutes of Health, 4 Center Dr., MSC 0445, Bethesda, MD 20892-0455. Phone: (301) 496-9869. Fax: (301) 480-1147. E-mail: bmoss{at}nih.gov
This article has been cited by other articles:
| J. Bacteriol. | Mol. Cell. Biol. | Microbiol. Mol. Biol. Rev. |
|---|
| Clin. Vaccine Immunol. | ALL ASM JOURNALS |
|---|