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Journal of Virology, January 2000, p. 8-15, Vol. 74, No. 1
The Marjorie B. Kovler Viral Oncology
Laboratories1 and the Department of
Radiation and Cellular Oncology,2 The
University of Chicago, Chicago, Illinois 60637
Received 20 July 1999/Accepted 15 September 1999
In uninfected cells the G2/M transition is regulated by
cyclin kinase complex containing cdc2 and, initially, cyclin A,
followed by cyclin B. cdc2 is downregulated through phosphorylation by wee-1 and myt-1 and upregulated by cdc-25C phosphatase. We have examined the accumulation and activities of these proteins in cells
infected with wild type and mutants of herpes simplex virus 1. The
results were as follows. (i) Cyclin A and B levels were reduced
beginning 4 h after infection and were undetectable at 12 to
16 h after infection. (ii) cdc2 protein also decreased in amount
but was detectable at all times after infection. In addition, a
fraction of cdc2 protein from infected cells exhibited altered electrophoretic mobility in denaturing gels. (iii) The levels of cdk7
or myt-1 proteins remained relatively constant throughout infection,
whereas the level of wee-1 was significantly decreased. (iv) cdc-25C
formed novel bands characterized by slower electrophoretic mobility
that disappeared after treatment with phosphatase. In addition, one
phosphatase-sensitive band reacted with MPM-2 antibody that recognizes
a phosphoepitope phosphorylated exclusively in M phase. (v) cdc2
accumulating in infected cells exhibited kinase activity. The activity
of cdc2 was higher in infected cell lysates than those of corresponding
proteins present in lysates of mock-infected cells even though cyclins
A and B were not detectable in lysates of infected cells. (vi) The
decrease in the levels of cyclins A and B, the increase in activity of
cdc2, and the hyperphosphorylation of cdc-25C were mediated by
UL13 and
0022-538X/0/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
The Disappearance of Cyclins A and B and the Increase in Activity
of the G2/M-Phase Cellular Kinase cdc2 in Herpes
Simplex Virus 1-Infected Cells Require Expression of the
22/US1.5 and UL13 Viral Genes
22/US1.5 gene products. In light of
its normal functions, the activated cdc2 kinase may play a role in the
changes in the morphology of the infected cell. These results are
consistent with the accruing evidence that herpes simplex virus
scavenges the cell for useful cell cycle proteins and subverts them for
its own use.
*
Corresponding author. Mailing address: The Marjorie B. Kovler Viral Oncology Laboratories, The University of Chicago, 910 E. 58th St., Chicago, IL 60637. Phone: (773) 702-1898. Fax: (773) 702-1631. E-mail: bernard{at}cummings.uchicago.edu.
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