Previous Article | Next Article 
Journal of Virology, July 2001, p. 6193-6198, Vol. 75, No. 13
0022-538X/01/$04.00+0 DOI: 10.1128/JVI.75.13.6193-6198.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Viral Interferon Regulatory Factor 1 of Kaposi's
Sarcoma-Associated Herpesvirus Binds to p53 and Represses
p53-Dependent Transcription and Apoptosis
Taegun
Seo,
Junsoo
Park,
Daeyoup
Lee,
Sun Gwan
Hwang, and
Joonho
Choe*
Department of Biological Sciences, Korea
Advanced Institute of Science and Technology, Daejeon 305-701, Korea
Received 15 February 2001/Accepted 30 March 2001
 |
ABSTRACT |
Kaposi's sarcoma-associated herpesvirus (KSHV) is related to the
development of Kaposi's sarcoma. Open reading frame K9 of KSHV encodes
viral interferon regulatory factor 1 (vIRF1), which functions as a
repressor of interferon- and IRF1-mediated signal transduction. In
addition, vIRF1 acts as an oncogene to induce cellular transformation.
Here we show that vIRF1 directly associates with the tumor suppressor
p53 and represses its functions. The vIRF1 interaction domains of p53
are the DNA binding domain (amino acids [aa] 100 to 300) and the
tetramerization domain (aa 300 to 393). p53 interacts with the central
region (aa 152 to 360) of vIRF1. vIRF1 suppresses p53-dependent
transcription and deregulates its apoptotic activity. These results
suggest that vIRF1 may regulate cellular function by inhibiting p53.
 |
TEXT |
The Kaposi's sarcoma
(KS)-associated herpesvirus (KSHV), also called human herpesvirus 8, is
a novel human gammaherpesvirus that plays a role in the development of
KS lesions, primary effusion lymphoma, and a subset of multicentric
Castleman's disease (2, 25). Analysis of the genomic
sequence of KSHV shows significant homologies with herpesvirus saimiri
and Epstein-Barr virus. The KSHV genome contains a unique set of
nonstructural genes that have homologies with genes encoding cellular
proteins (22). For example, the K9 open reading frame of
KSHV, which encodes viral interferon regulatory factor 1 (vIRF1), shows
significant homology with the cellular IRF. vIRF1 is a 449-amino-acid
(aa) protein whose synthesis is induced by tetradecanoyl phorbol
acetate (TPA) (20, 23). The expression of antisense RNA
to vIRF1 down-regulates the expression of specific KSHV genes in
BCBL-1 cells, suggesting that vIRF1 may regulate KSHV gene expression
(13).
In transient-transfection assays, vIRF1 represses cellular interferon-
and IRF1-mediated transcriptional activation (13, 26).
vIRF1 transforms NIH 3T3 cells, and NIH 3T3 cells that stably express
vIRF1 display features of a malignant fibrosarcoma in nude mice
(4, 13). In addition, vIRF1 inhibits tumor necrosis factor
alpha-mediated apoptosis (1). These facts strongly suggest that vIRF1 augments the tumorigenicity of KSHV. vIRF1 also associates with p300/CBP (CREB binding protein), thus inhibiting the
transactivation of CBP and the histone acetyltransferase activity of
p300 (1, 12, 24).
The tumor suppressor p53 is absent from numerous types of human cancer
cells (7). p53 is a key regulator of a wide range of
cellular activities, including cell cycle regulation, apoptosis, response to DNA damage, differentiation, and angiogenesis (11, 15). Several viral oncoproteins (simian virus 40 large T
antigen, papillomavirus E6, adenovirus E1B, and hepatitis B virus X
protein) bind to p53 and modulate its function. p53 contains four
distinct functional domains: the transcriptional activation domain at
the amino terminus (aa 1 to 42), the DNA binding domain (DBD) in the central region (aa 102 to 292), the tetramerization domain (TD; aa 323 to 356), and the regulatory domain (aa 363 to 393) (15).
vIRF1 associates with p53 in vivo.
Because vIRF1 causes
transformation and inhibits tumor necrosis factor-mediated apoptosis,
we investigated whether vIRF1 interacts with p53. By using the calcium
phosphate method (6), 293T cells were transfected with
glutathione S-transferase (GST), GST-vIRF, and hemagglutinin
(HA)-p53 expression plasmids (pEBG, pEBG/vIRF, and pcDNA3/HA-53,
respectively). Forty-eight hours after transfection, the cells were
lysed with EBC buffer (50 mM Tris-HCl [pH 7.5], 120 mM NaCl, 0.5%
Nonidet P-40, 50 mM NaF, 200 µM sodium orthovanadate, 1 mM
phenylmethylsulfonyl fluoride). The cell extracts were then incubated
with glutathione-Sepharose 4B beads (Amersham Pharmacia Biotech,
Uppsala, Sweden) to precipitate the GST and GST-vIRF1 proteins, and the
precipitated proteins were immunoblotted with an anti-HA antibody.
HA-p53 coprecipitated with GST-vIRF1 but did not coprecipitate with GST
(Fig. 1A, top). To show that the GST,
GST-vIRF1, and HA-p53 proteins were expressed properly in the
transfected cells, we performed separate immunoblot experiments with
anti-GST and anti-HA monoclonal antibodies (Fig. 1A, middle and bottom,
respectively). 293T cells were also transfected with vIRF1
(pcDNA3/vIRF1) and HA-p53 (pcDNA3/HA-p53) expression plasmids. The cell
extracts were immunoprecipitated with an anti-HA monoclonal antibody,
and again the vIRF1 protein coimmunoprecipitated with HA-p53 (Fig. 1B).

View larger version (26K):
[in this window]
[in a new window]
|
FIG. 1.
In vivo interaction of vIRF1 with p53. (A) A GST
expression plasmid (pEBG) or a GST-vIRF1 expression plasmid
(pEBG/vIRF1) was cotransfected with an HA-p53 expression plasmid
(pcDNA3/HA-p53) into 293T cells. Whole-cell extracts were prepared
48 h after transfection and precipitated with
glutathione-Sepharose 4B beads. The precipitated proteins were washed
and resolved by sodium dodecyl sulfate-polyacrylamide gel
electrophoresis (SDS-PAGE). GST fusion protein and HA-p53 were detected
by Western blotting with anti-HA (top and bottom) and anti-GST
(middle). Lanes: 1, GST alone; 2, no expression plasmid; 3, GST with
HA-p53; 4, GST-vIRF1 with HA-p53. (B) A vIRF1 expression plasmid
(pcDNA3/vIRF1) was cotransfected with or without the HA-p53 expression
plasmid. Whole-cell extracts were incubated with protein G resin after
preincubation with anti-HA. The resulting immunoprecipitates were
washed and resolved by SDS-PAGE. vIRF1 and HA-p53 were detected by
Western blotting with anti-vIRF1 rabbit polyclonal antibody (top) or
with anti-HA ( HA) antibody (bottom). Lanes: 1 and 3, vIRF1 alone; 2 and 4, vIRF1 with HA-p53. IP, immunoprecipitation. Anti-vIRF1
polyclonal antibody was obtained from postimmune sera collected from
rabbits immunized with the GST-vIRF1 fusion protein. (C) In vivo
interaction of vIRF1 with p53 in KSHV-infected BCBL-1 cells. BCBL-1
cells were treated with TPA as previously described (20),
and whole-cell extracts were prepared after the indicated number of
hours. vIRF1 expression was detected by Western blotting with
anti-vIRF1 antibody (left). Whole-cell extracts from BJAB and BCBL-1
cells were immunoblotted with anti-vIRF1 and anti-p53 (lanes 1 and 2).
Direct coimmunoprecipitation (IP) was performed by using BCBL-1 cells
after TPA stimulation. BCBL-1 and BJAB cells (1 × 107
cells) were harvested 48 h after TPA stimulation, and whole-cell
extracts were incubated with protein G resin after being preincubated
with either anti-p53 ( p53) (lanes 3 and 4) or anti-HA ( HA) (lane
5) antibody. vIRF1 was detected by Western blotting with anti-vIRF1
(right top) or anti-p53 (right bottom) antibody.
|
|
To determine whether vIRF1 and p53 interact in a KSHV-infected cell
line, we performed coimmunoprecipitation assays with KSHV-infected
BCBL-1 cells. First, expression of vIRF1 was stimulated by treatment
of
the cells with TPA (Fig.
1C, left). Total lysates of BJAB and
BCBL-1
cells were immunoblotted with an anti-vIRF1 polyclonal
antibody and an
anti-p53 monoclonal antibody, DO-I (Santa Cruz
Biotechnology, Santa
Cruz, Calif.) (Fig.
1C, lanes 1 and 2). The
cells were then
immunoprecipitated with either anti-p53 antibody
or anti-HA antibody.
In addition, vIRF1 coimmunoprecipitated with
p53 in the KSHV-infected
BCBL-1 cells (Fig.
1C, lane 4). In contrast,
vIRF1 was not detected in
KSHV-negative BJAB cell extracts or
by immunoprecipitation with anti-HA
(Fig.
1C, lanes 3 and 5).
These results demonstrate that vIRF1
interacts with
p53.
vIRF1 interacts with the DBD and TD of p53, whereas p53 interacts
with the central region of vIRF1.
To map the vIRF1 binding domain
in p53, we performed GST pulldown assays (10) by using
35S-labeled, in vitro-translated vIRF1 and a
series of GST-p53 deletion mutants (Fig.
2A). The transcriptional activation (TA)
domain (aa 1 to 42) of p53 did not interact with vIRF1, whereas the p53 DBD (aa 100 to 300) and TD (aa 300 to 393) interacted with vIRF1. The
vIRF1 binding affinity of the p53 DBD was slightly stronger than that
of the TD. These results show that vIRF1 directly interacts with p53
through its DBD and TD.

View larger version (22K):
[in this window]
[in a new window]
|
FIG. 2.
Identification of domains involved in vIRF1-p53
interaction. (A) Top, schematic representation of p53 and its
functional domains. The TA domain (aa 1 to 42), DBD (aa 1 to 42), and
TD (aa 300 to 393) are shown. Bottom, GST pulldown assays
(10) performed with wild-type and mutant GST-p53 fusion
proteins by using 35S-labeled, in vitro-translated vIRF1.
The input (20%) and GST pulldown mixtures were resolved by SDS-PAGE,
and vIRF1 was visualized by autoradiography. (B) Left, schematic
representation of vIRF1 and its deletion mutants. Right, an experiment
similar to that described for panel A that was performed by using the
GST-p53 and 35S-labeled, in vitro-translated vIRF1 and
vIRF1 mutant proteins.
|
|
To determine the p53 binding domain within vIRF1, we constructed
the vIRF1 deletion mutants vIRF1(1-360), vIRF1(1-152), and
vIRF1(152-360) (Fig.
2B). GST pulldown assays were performed by
using
35S-labeled, in vitro-translated vIRF1 (and vIRF1
mutants) and GST-p53
(Fig.
2B). Only vIRF1(1-360) and vIRF1(152-360)
interacted with
GST-p53 (Fig.
2C). These results indicate that the p53
interaction
domain within vIRF1 is located in the central region (aa
152 to
360) of
vIRF1.
vIRF1 represses p53-dependent transcription.
To test whether
the vIRF1 protein modulates p53-mediated transcription, we transiently
cotransfected 293T cells with a reporter plasmid that contained
synthetic p53 response elements fused to the gene for luciferase
(PG13-Luc) and a vIRF1 expression plasmid (pcDNA3-vIRF1) with or
without an HA-p53 expression plasmid (pcDNA3/HA-p53). The cells were
transfected by the calcium phosphate method (6), harvested
24 h after transfection, and resuspended in cell lysis buffer. The
insoluble fraction was removed by centrifugation, and the luciferase
activity in the supernatant was measured with a luminometer (EG&G
Berthold, Pforzheim, Germany). In each transfection assay, a Rous
sarcoma virus
-galactosidase expression plasmid was
cotransfected and
-galactosidase activity was measured as an
internal control for transfection efficiency. In the presence of vIRF1,
p53-driven transcription of the luciferase gene was inhibited in a
dose-dependent manner (Fig. 3A).
Expression of HA-p53 was monitored by a Western blot assay, which
showed that the level of HA-p53 was not changed by the presence of
vIRF1. Similarly, we carried out cotransfection assays in p53-null
Saos2 cells by using either the PG13-Luc reporter or the WWP-Luc
reporter, which contains an authentic p21 promoter. For both reporters, cotransfection with the vIRF1 expression plasmid repressed luciferase activity in a dose-dependent manner (Fig. 3B and C). These results indicate that HA-p53 can substitute for endogenous p53. Transfection experiments were also performed with the BJAB B-cell lymphoma cell
line. BJAB cells were transfected by electroporation as described previously (14). As in 293T and Saos2 cells, vIRF1
repressed p53-mediated transcription in BJAB cells (Fig. 3D).

View larger version (27K):
[in this window]
[in a new window]
|
FIG. 3.
vIRF1 represses p53-dependent transcription. Luciferase
activity was measured with a luminometer. The total amount of
transfected DNA in each experiment was kept constant by the addition of
a blank vector (pcDNA3). The activity of the reporter alone was
normalized to a value of 1, and each luciferase measurement was
normalized to the internal control, -galactosidase activity. Each
experiment was carried out at least three times. (A) A synthetic
p53 response element fused to a luciferase gene (PG13-Luc) was
inhibited by vIRF1 in the presence of p53 in 293T cells. 293T cells
were cotransfected with PG13-Luc (1 µg), a -galactosidase
expression plasmid (0.5 µg), a p53 expression plasmid (pcDNA3/HA-p53)
(0.5 µg), and increasing amounts of an expression plasmid encoding
vIRF1 (pcDNA3/vIRF1). Equal amounts of total cellular extracts were
resolved by SDS-PAGE and subjected to HA-specific immunoblotting. (B)
PG13-Luc was inhibited by vIRF1 in the presence of p53. Saos2 cells
were cotransfected with PG13-Luc (1 µg), a -galactosidase
expression plasmid (RSV/ -gal) (0.5 µg), a p53 expression plasmid
(pcDNA3/HA-p53) (0.5 µg), and increasing amounts of an expression
plasmid encoding vIRF1 (pcDNA3/vIRF1). (C) The WWP-Luc plasmid was
inhibited by vIRF1 in the presence of p53. Saos2 cells were
cotransfected with WWP-Luc (1 µg) and the other plasmids listed in
panel B. (D) vIRF1 represses p53-dependent transcription in BJAB cells.
BJAB cells were cotransfected by electroporation (14) with
PG13-Luc (5 µg), an HA-p53 expression plasmid, and a vIRF1 expression
plasmid. (E) vIRF1 represses transcriptional activation by p53 and does
not influence an unrelated transcriptional activator. 293T cells were
cotransfected with a Gal4-Luc reporter plasmid (pFR-Luc) (1 µg), a
vIRF1 expression plasmid, and either a Gal4-p53 expression plasmid (0.5 µg) or a Gal4-SP1 expression plasmid (0.5 µg). (F) vIRF1 does not
repress transcriptional activation by p53(TA) (aa 1 to 42). 293T cells
were cotransfected with pFR-Luc (1 µg), a Gal4-p53(TA) expression
plasmid, and a vIRF1 expression plasmid. (G) vIRF1 represses
p53-induced p21 expression in 293T cells. A vIRF1 expression plasmid
(pcDNA3/vIRF1) and an HA-p53 expression plasmid (pcDNA3/HA-p53) were
cotransfected into 293T cells by the calcium phosphate method. Cells
were harvested 48 h after transfection. Lanes: 1, no expression
plasmid; 2, pcDNA3/HA-p53 (7 µg) plus pcDNA3 (15 µg); 3, pcDNA3/HA-p53 (7 µg) plus pcDNA3/vIRF1 (15 µg); 4, pcDNA3 (7 µg)
plus pcDNA3/vIRF1 (15 µg). p21 was detected with a monoclonal
antibody to p21 (top), and -actin was detected with a monoclonal
antibody to -actin (bottom).
|
|
To test whether vIRF1 directly represses the transcriptional activation
activity of p53, we carried out cotransfection assays
with 293T cells
by using a Gal4-p53 expression plasmid and pFR-Luc,
which contains five
Gal4 binding sites, as the reporter. Cotransfection
with a vIRF1
expression plasmid repressed Gal4-p53-driven luciferase
expression in a
dose-dependent manner, indicating that vIRF1 can
repress the
transcriptional activation activity of p53 (Fig.
3E).
To test whether
the effect of vIRF1 on the transcriptional activity
of p53 is specific,
we replaced Gal4-p53 with a Gal4-SP1 fusion
protein in the transfection
assay. Cotransfection with the vIRF1
expression plasmid did not alter
Gal4-SP1-driven luciferase activity
expression.
To test whether vIRF1-p53 interaction is important in the repression of
p53 transactivation, we carried out cotransfection
assays by using
Gal4-p53(TA) (aa 1 to 42) in 293T cells. The TA
domain of p53 did not
interact with vIRF1 in GST pulldown assays
(Fig.
2A). Unlike Gal4-p53,
Gal4-p53(TA) was not inhibited by
a vIRF1 expression plasmid (Fig.
3E
and F). These data show that
protein-protein interaction between p53
and vIRF1 is necessary
for inhibition of the transactivation of
p53.
To test whether vIRF1 down-regulates p21 expression in vivo, we
measured the p21 expression level in 293T cells by immunoblotting.
BJAB
cells in 100-mm-diameter dishes were cotransfected by the
calcium phosphate method (
6), harvested 48 h after
transfection,
and immunoblotted with an anti-p21 monoclonal antibody
(Santa
Cruz Biotechnology). In the presence of p53, p21 expression was
dramatically increased whereas p21 expression was decreased upon
cotransfection with the vIRF1 expression plasmid (Fig.
3G, top).
To
show that the total protein concentration in each lane was
the same, we
performed Western blot assays with an antibody to

-actin (Fig.
3G,
bottom). These results demonstrate that vIRF1
suppresses p53-mediated
p21 expression in 293T cells and are consistent
with the above results
showing that vIRF1 inhibits p53-mediated
transcription.
vIRF1 deregulates p53-induced apoptosis in Saos2 cells.
To
examine the effect of vIRF1 on p53-mediated apoptosis, we performed
terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end
labeling (TUNEL) assays (5) with p53-null Saos2 cells. The
TUNEL reaction was performed by using an in situ cell detection kit as
specified by the manufacturer (Roche, Mannheim, Germany). Forty-eight
hours after transfection, successfully transfected Saos2 cells were
subjected to the TUNEL reaction. The TUNEL reaction used
fluorescein-5-isothiocyanate as the labeling reagent, and TUNEL-positive (apoptotic) cells showed green nuclei. Transfection of
cells with a p53 expression plasmid increased the number of TUNEL-positive cells, while cotransfection of vIRF1 with a p53 expression plasmid decreased the number of TUNEL-positive cells (Fig.
4A). TUNEL-positive cells represented
3.1, 18.7, 9.2, and 4.6% of the total cell population when expressing
no protein, p53, p53 in combination with vIRF1, and vIRF1 alone,
respectively (Fig. 4B). These data show that vIRF1 inhibits the
apoptotic activity of p53.

View larger version (8K):
[in this window]
[in a new window]
|
FIG. 4.
vIRF1 deregulates p53-induced apoptosis in Saos2 cells.
Saos2 cells grown on coverslips in 35-mm-diameter dishes were
transfected with Superfect transfection reagent (Qiagen, Hilden,
Germany). Forty-eight hours after transfection, cells were fixed and
the TUNEL reaction was performed as recommended by the manufacturer
(Roche). The analyses were performed with a Zeiss confocal microscope
with fluorescein isothiocyanate filter sets. (A) Left top, mock
transfection (no expression plasmid); right top, pcDNA3/HA-p53 (1 µg)
plus pcDNA3 (1 µg); bottom left, pcDNA3/HA-p53 (1 µg) plus
pcDNA3/vIRF1 (1 µg); bottom right, pcDNA3/vIRF1 (1 µg) plus pcDNA3
(1 µg). Magnification, ×100. In the insert at the top right, the
magnification of the cell indicated by the arrow is ×400. (B)
Schematic representation of TUNEL-positive cell percentages. The bars
represent the percentages of transfected cells that showed apoptosis;
apoptosis was determined by counting the green dead cells. The
values shown are means calculated from two duplicate
experiments. A total of 1,000 cells were counted in each
experiment.
|
|
Our results suggest that vIRF1 interacts with tumor suppressor p53 and
is capable of repressing p53-mediated transcription
and apoptosis. The
observation that vIRF1 interacts with the DBD
and TD of p53 suggests
that vIRF1 inhibits the transcriptional
activation activity of p53 by
interfering with the DNA binding
or tetramerization of p53. Therefore,
we tested the ability of
p53 to bind DNA in the presence and absence of
vIRF1. vIRF1 did
not diminish the DNA binding affinity of p53 in vitro
(data not
shown). In addition, we showed that vIRF1 also inhibited the
transactivation
of Gal4-p53 (Fig.
3D), indicating that the suppression
of p53
transcriptional activation by vIRF1 does not require the direct
DNA binding ability of p53. Another potential mechanism for vIRF1
inhibition of p53 activity might be blocking of the tetramerization
of
p53. It is well known that p53 forms tetramers and that tetramerization
is required for efficient cell growth suppression by p53 (
9,
19). Through binding to the TD of p53, vIRF1 may block
tetramerization,
resulting in the inhibition of p53 function. A third
possible
mechanism for the repression of p53-regulated promoters by
vIRF1
might be sequestration of a common coactivator, such as p300/CBP.
Because vIRF1 is known to interact with p300/CBP, vIRF1 may inhibit
transcriptional activation by p53 by sequestering this coactivator.
Like papillomavirus E6, vIRF1 interacts with p53 and p300/CBP.
In the
case of E6, repression of p53-regulated promoters is dependent
on both
the E6-p53 and E6-p300/CBP interactions (
18). In the
case
of vIRF1, vIRF1-p53 interaction is important for the repression
of
p53-regulated promoters since vIRF1 does not repress the
transactivation
of p53(TA), which does not interact with vIRF1 (Fig.
3F). Further
study is needed to decipher the precise mechanism of vIRF1
inhibition
of p53
function.
p53 is known to be a key regulator of growth arrest through the
induction of p21 and growth arrest- and DNA damage-inducible
protein
45. p21 was identified as a potent inhibitor of several
cyclin-dependent kinases (CDKs), including cyclin D-CDK4/6, cyclin
E-CDK2, and cyclin A-CDK2 (
15). p21 leads to inhibition of
the
cyclin D-CDK4/6 complex and subsequent accumulation of the
unphosphorylated
form of the retinoblastoma protein, which arrests
cells in the
G
1 phase of the cell cycle. Because
vIRF1 repressed p53-induced
p21 expression (Fig.
3G), vIRF1 might
induce cell proliferation
by diminishing p21 expression. In addition,
vIRF1 deregulates
p53-induced apoptosis (Fig.
4). It is well known that
stable expression
of vIRF1 leads to the transformation of NIH 3T3
cells, resulting
in morphologic changes, and the induction of malignant
fibrosarcoma
in nude mice (
4,
13); however, the molecular
mechanism of
this phenomenon has not been fully elucidated. To
transform cells
and induce tumors, tumor suppressor genes must be
inactivated
and this inactivation can occur in a number of ways.
Because p53
induces not only growth arrest but also apoptosis and DNA
repair,
p53 is the major target for tumorigenic viral proteins such as
E6 and the simian virus 40 large T antigen (
15). Our
results
begin to explain the transforming activity of
vIRF1.
Previous reports showed that latency-associated nuclear protein 1 (LANA1), K-bZIP, and vIRF3/LANA2 of KSHV interact with p53
and that
these interactions result in the repression of p53-mediated
transcription and apoptosis (
3,
16,
21). Recently, Rivas
et al. (
21) reported that KSHV LANA2 is a B-cell-specific
latent
viral protein and that it inhibits p53. Both vIRF1 and
vIRF3/LANA2
bind to the TD of p53, but vIRF1 also binds to the DBD of
p53.
The p53-inhibiting activity of vIRF1 is similar to that of
vIRF3/LANA2,
suggesting that IRF homologues of KSHV may regulate the
cell cycle
by targeting p53. Although vIRF1 is not generally expressed
in
KS, it seems to be important in multicentric Castleman's disease
(
8,
17). vIRF1 may contribute to the development of B-cell
hyperplasia in Castleman's disease by repressing p53-induced
apoptosis.
 |
ACKNOWLEDGMENTS |
This work was supported in part by grants from the National
Research Laboratory Program of the Korea Institute of Science and
Technology Evaluation and Planning (KISTEP), the Korea Science and
Engineering Foundation (KOSEF) through the Protein Network Research
Center at Yonsei University, and the BK21 Program of the Ministry of
Education, Korea.
 |
FOOTNOTES |
*
Corresponding author. Mailing address: Department of
Biological Sciences, Korea Advanced Institute of Science and
Technology, Daejeon 305-701, Korea. Phone: 82-42-869-2630. Fax:
82-42-869-5630. E-mail: jchoe{at}mail.kaist.ac.kr.
 |
REFERENCES |
| 1.
|
Burý ek, L.,
W.-S. Yeow,
B. Lubyová,
M. Kellum,
S. L. Schafer,
Y. Q. Huang, and P. M. Pitha.
1999.
Functional analysis of human herpesvirus 8-encoded viral interferon regulatory factor 1 and its association with cellular interferon regulatory factors and p300.
J. Virol.
73:7334-7342[Abstract/Free Full Text].
|
| 2.
|
Chang, Y.,
E. Cesarman,
M. S. Pessin,
F. Lee,
J. Culpepper,
D. M. Knowles, and P. S. Moore.
1994.
Identification of herpesvirus-like DNA sequences in AIDS-associated Kaposi's sarcoma.
Science
266:1865-1869[Abstract/Free Full Text].
|
| 3.
|
Friborg, J.,
W. Kong,
M. O. Hottiger, and G. J. Nabel.
1999.
p53 inhibition by the LANA protein of KSHV protects against cell death.
Nature
402:889-894[Medline].
|
| 4.
|
Gao, S.,
J. C. Boshoff,
S. Jayachandra,
R. A. Weiss,
Y. Chang, and P. S. Moore.
1997.
KSHV ORF K9 (vIRF) is an oncogene which inhibits the interferon signaling pathway.
Oncogene
15:1979-1985[CrossRef][Medline].
|
| 5.
|
Gorczyca, W.,
K. Bigman,
A. Mittelman,
T. Ahmed,
J. Gong,
M. R. Melamed, and Z. Darzynkiewicz.
1993.
Induction of DNA strand breaks associated with apoptosis during treatment of leukemias.
Leukemia
7:659-670[Medline].
|
| 6.
|
Graham, F. L.,
J. Smiley,
W. C. Russell, and R. Nairn.
1977.
Characteristics of a human cell line transformed by DNA from human adenovirus type 5.
J. Gen. Virol.
36:59-74[Abstract/Free Full Text].
|
| 7.
|
Hollstein, M.,
D. Sidransky,
B. Vogelstein, and C. C. Harris.
1991.
p53 mutations in human cancers.
Science
253:49-53[Abstract/Free Full Text].
|
| 8.
|
Katano, H.,
Y. Sato,
T. Kurata,
S. Mori, and T. Sata.
2000.
Expression and localization of human herpesvirus 8-encoded proteins in primary effusion lymphoma, Kaposi's sarcoma, and multicentric Castleman's disease.
Virology
269:335-344[CrossRef][Medline].
|
| 9.
|
Kraiss, S.,
A. Quaiser,
M. Oren, and M. Montenarh.
1988.
Oligomerization of oncoprotein p53.
J. Virol.
62:4737-4744[Abstract/Free Full Text].
|
| 10.
|
Lee, D.,
B. Lee,
J. Kim,
D. W. Kim, and J. Choe.
2000.
cAMP response element-binding protein-binding protein binds to human papillomavirus E2 protein and activates E2-dependent transcription.
J. Biol. Chem.
275:7045-7051[Abstract/Free Full Text].
|
| 11.
|
Levine, A. J.
1997.
p53, the cellular gatekeeper for growth and division.
Cell
88:323-331[CrossRef][Medline].
|
| 12.
|
Li, M.,
B. Damania,
X. Alvarez,
V. Ogryzko,
K. Ozato, and J. U. Jung.
2000.
Inhibition of p300 histone acetyltransferase by viral interferon regulatory factor.
Mol. Cell. Biol.
20:8254-8263[Abstract/Free Full Text].
|
| 13.
|
Li, M.,
H. Lee,
J. Guo,
F. Neipel,
B. Fleckenstein,
K. Ozato, and J. U. Jung.
1998.
Kaposi's sarcoma-associated herpesvirus viral interferon regulatory factor.
J. Virol.
72:5433-5440[Abstract/Free Full Text].
|
| 14.
|
Lukac, D. M.,
J. R. Kirshner, and D. Ganem.
1999.
Transcriptional activation by the product of open reading frame 50 of Kaposi's sarcoma-associated herpesvirus is required for lytic viral reactivation in B cells.
J. Virol.
73:9348-9361[Abstract/Free Full Text].
|
| 15.
|
May, P., and E. May.
1999.
Twenty years of p53 research: structural and functional aspects of the p53 protein.
Oncogene
18:7621-7636[CrossRef][Medline].
|
| 16.
|
Park, J.,
T. Seo,
S. Hwang,
D. Lee,
Y. Gwack, and J. Choe.
2000.
The K-bZIP protein from Kaposi's sarcoma-associated herpesvirus interacts with p53 and represses its transcriptional activity.
J. Virol.
74:11977-11982[Abstract/Free Full Text].
|
| 17.
|
Parravicini, C.,
B. Chandran,
M. Corbellino,
E. Berti,
M. Paulli,
P. S. Moore, and Y. Chang.
2000.
Differential viral protein expression in Kaposi's sarcoma-associated herpesvirus-infected disease: Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease.
Am. J. Pathol.
156:743-749[Abstract/Free Full Text].
|
| 18.
|
Patel, D.,
S. M. Huang,
L. A. Baglia, and D. J. McCance.
1999.
The E6 protein of human papillomavirus type 16 binds to and inhibits co-activation by CBP and p300.
EMBO J.
18:5061-5072[CrossRef][Medline].
|
| 19.
|
Pietenpol, J. A.,
T. Tokino,
S. Thiagalingam,
W. S. el-Deiry,
K. W. Kinzler, and B. Vogelstein.
1994.
Sequence-specific transcriptional activation is essential for growth suppression by p53.
Proc. Natl. Acad. Sci. USA
91:1998-2002[Abstract/Free Full Text].
|
| 20.
|
Renne, R.,
W. Zhong,
B. Herndier,
M. McGrath,
N. Abbey,
D. Kedes, and D. Ganem.
1996.
Lytic growth of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in culture.
Nat. Med.
2:342-346[CrossRef][Medline].
|
| 21.
|
Rivas, C.,
A. Thlick,
C. Parravicini,
P. S. Moore, and Y. Chang.
2001.
Kaposi's sarcoma-associated herpesvirus LANA2 is a B-cell-specific latent viral protein that inhibits p53.
J. Virol.
75:429-438[Abstract/Free Full Text].
|
| 22.
|
Russo, J. J.,
R. A. Bohenzky,
M. C. Chien,
J. Chen,
M. Yan,
D. Maddalena,
J. P. Parry,
D. Peruzzi,
I. S. Edelman,
Y. Chang, and P. S. Moore.
1996.
Nucleotide sequence of the Kaposi sarcoma-associated herpesvirus (HHV8).
Proc. Natl. Acad. Sci. USA
93:14862-14867[Abstract/Free Full Text].
|
| 23.
|
Sarid, R.,
O. Flore,
R. A. Bohenzky,
Y. Chang, and P. S. Moore.
1998.
Transcription mapping of the Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) genome in a body cavity-based lymphoma cell line (BC-1).
J. Virol.
72:1005-1012[Abstract/Free Full Text].
|
| 24.
|
Seo, T.,
D. Lee,
B. Lee,
J. H. Chung, and J. Choe.
2000.
Viral interferon regulatory factor 1 of Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) binds to and inhibits transactivation of CREB-binding protein.
Biochem. Biophys. Res. Commun.
270:23-27[CrossRef][Medline].
|
| 25.
|
Soulier, J.,
L. Grollet,
E. Oksenhendler,
P. Cacoub,
D. Cazals-Hatem,
P. Babinet,
M. F. d'Agay,
J. P. Clauvel,
M. Raphael,
L. Degos, and F. Sigaux.
1995.
Kaposi's sarcoma-associated herpesvirus-like DNA sequences in multicentric Castleman's disease.
Blood
86:1276-1280[Abstract/Free Full Text].
|
| 26.
|
Zimring, J. C.,
S. Goodbourn, and M. K. Offermann.
1998.
Human herpesvirus 8 encodes an interferon regulatory factor (IRF) homolog that represses IRF-1-mediated transcription.
J. Virol.
72:701-707[Abstract/Free Full Text].
|
Journal of Virology, July 2001, p. 6193-6198, Vol. 75, No. 13
0022-538X/01/$04.00+0 DOI: 10.1128/JVI.75.13.6193-6198.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Boulanger, E., Marchio, A., Hong, S.-S., Pineau, P.
(2009). Mutational analysis of TP53, PTEN, PIK3CA and CTNNB1/{beta}-catenin genes in human herpesvirus 8-associated primary effusion lymphoma. haematol
94: 1170-1174
[Abstract]
[Full Text]
-
Lee, H.-R., Toth, Z., Shin, Y. C., Lee, J.-S., Chang, H., Gu, W., Oh, T.-K., Kim, M. H., Jung, J. U.
(2009). Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 4 Targets MDM2 To Deregulate the p53 Tumor Suppressor Pathway. J. Virol.
83: 6739-6747
[Abstract]
[Full Text]
-
Choi, Y. B., Nicholas, J.
(2008). Autocrine and Paracrine Promotion of Cell Survival and Virus Replication by Human Herpesvirus 8 Chemokines. J. Virol.
82: 6501-6513
[Abstract]
[Full Text]
-
Park, J., Lee, M.-S., Yoo, S.-M., Jeong, K. W., Lee, D., Choe, J., Seo, T.
(2007). Identification of the DNA Sequence Interacting with Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 1. J. Virol.
81: 12680-12684
[Abstract]
[Full Text]
-
Petre, C. E., Sin, S.-H., Dittmer, D. P.
(2007). Functional p53 Signaling in Kaposi's Sarcoma-Associated Herpesvirus Lymphomas: Implications for Therapy. J. Virol.
81: 1912-1922
[Abstract]
[Full Text]
-
Rezaee, S. A. R., Cunningham, C., Davison, A. J., Blackbourn, D. J.
(2006). Kaposi's sarcoma-associated herpesvirus immune modulation: an overview. J. Gen. Virol.
87: 1781-1804
[Abstract]
[Full Text]
-
Fuld, S., Cunningham, C., Klucher, K., Davison, A. J., Blackbourn, D. J.
(2006). Inhibition of Interferon Signaling by the Kaposi's Sarcoma-Associated Herpesvirus Full-Length Viral Interferon Regulatory Factor 2 Protein. J. Virol.
80: 3092-3097
[Abstract]
[Full Text]
-
Shin, Y. C., Nakamura, H., Liang, X., Feng, P., Chang, H., Kowalik, T. F., Jung, J. U.
(2006). Inhibition of the ATM/p53 Signal Transduction Pathway by Kaposi's Sarcoma-Associated Herpesvirus Interferon Regulatory Factor 1. J. Virol.
80: 2257-2266
[Abstract]
[Full Text]
-
Takemoto, M., Koike, M., Mori, Y., Yonemoto, S., Sasamoto, Y., Kondo, K., Uchiyama, Y., Yamanishi, K.
(2005). Human Herpesvirus 6 Open Reading Frame U14 Protein and Cellular p53 Interact with Each Other and Are Contained in the Virion. J. Virol.
79: 13037-13046
[Abstract]
[Full Text]
-
Klass, C. M., Krug, L. T., Pozharskaya, V. P., Offermann, M. K.
(2005). The targeting of primary effusion lymphoma cells for apoptosis by inducing lytic replication of human herpesvirus 8 while blocking virus production. Blood
105: 4028-4034
[Abstract]
[Full Text]
-
Seo, T., Park, J., Choe, J.
(2005). Kaposi's Sarcoma-Associated Herpesvirus Viral IFN Regulatory Factor 1 Inhibits Transforming Growth Factor-{beta} Signaling. Cancer Res.
65: 1738-1747
[Abstract]
[Full Text]
-
Dornan, D., Eckert, M., Wallace, M., Shimizu, H., Ramsay, E., Hupp, T. R., Ball, K. L.
(2004). Interferon Regulatory Factor 1 Binding to p300 Stimulates DNA-Dependent Acetylation of p53. Mol. Cell. Biol.
24: 10083-10098
[Abstract]
[Full Text]
-
Pozharskaya, V. P., Weakland, L. L., Zimring, J. C., Krug, L. T., Unger, E. R., Neisch, A., Joshi, H., Inoue, N., Offermann, M. K.
(2004). Short Duration of Elevated vIRF-1 Expression during Lytic Replication of Human Herpesvirus 8 Limits Its Ability To Block Antiviral Responses Induced by Alpha Interferon in BCBL-1 Cells. J. Virol.
78: 6621-6635
[Abstract]
[Full Text]
-
Takemoto, M., Mori, Y., Ueda, K., Kondo, K., Yamanishi, K.
(2004). Productive human herpesvirus 6 infection causes aberrant accumulation of p53 and prevents apoptosis. J. Gen. Virol.
85: 869-879
[Abstract]
[Full Text]
-
Lubyova, B., Kellum, M. J., Frisancho, A. J., Pitha, P. M.
(2004). Kaposi's Sarcoma-associated Herpesvirus-encoded vIRF-3 Stimulates the Transcriptional Activity of Cellular IRF-3 and IRF-7. J. Biol. Chem.
279: 7643-7654
[Abstract]
[Full Text]
-
Dourmishev, L. A., Dourmishev, A. L., Palmeri, D., Schwartz, R. A., Lukac, D. M.
(2003). Molecular Genetics of Kaposi's Sarcoma-Associated Herpesvirus (Human Herpesvirus 8) Epidemiology and Pathogenesis. Microbiol. Mol. Biol. Rev.
67: 175-212
[Abstract]
[Full Text]
-
Cunningham, C., Barnard, S., Blackbourn, D. J., Davison, A. J.
(2003). Transcription mapping of human herpesvirus 8 genes encoding viral interferon regulatory factors. J. Gen. Virol.
84: 1471-1483
[Abstract]
[Full Text]
-
Wang, X.-P., Gao, S.-J.
(2003). Auto-activation of the transforming viral interferon regulatory factor encoded by Kaposi's sarcoma-associated herpesvirus (human herpesvirus-8). J. Gen. Virol.
84: 329-336
[Abstract]
[Full Text]
-
Seo, T., Lee, D., Shim, Y. S., Angell, J. E., Chidambaram, N. V., Kalvakolanu, D. V., Choe, J.
(2002). Viral Interferon Regulatory Factor 1 of Kaposi's Sarcoma-Associated Herpesvirus Interacts with a Cell Death Regulator, GRIM19, and Inhibits Interferon/Retinoic Acid-Induced Cell Death. J. Virol.
76: 8797-8807
[Abstract]
[Full Text]
-
Lee, D., Kim, J. W., Seo, T., Hwang, S. G., Choi, E.-J., Choe, J.
(2002). SWI/SNF Complex Interacts with Tumor Suppressor p53 and Is Necessary for the Activation of p53-mediated Transcription. J. Biol. Chem.
277: 22330-22337
[Abstract]
[Full Text]