University of Nebraska - Lincoln
DigitalCommons@University of Nebraska - Lincoln
Dissertations and Theses in Biological Sciences Biological Sciences, School of
5-2011
Investigation of Bovine Herpesvirus 1 (BHV-1)
Encoded Infected Cell Protein 0 (bICP0)
Natasha N. Gaudreault
University of Nebraska-Lincoln,
Follow this and additional works at: http://digitalcommons.unl.edu/bioscidiss
Part of the Laboratory and Basic Science Research Commons, and the Virology Commons
Gaudreault, Natasha N., "Investigation of Bovine Herpesvirus 1 (BHV-1) Encoded Infected Cell Protein 0 (bICP0)" (2011).
Dissertations and Theses in Biological Sciences. 26.
http://digitalcommons.unl.edu/bioscidiss/26
This Article is brought to you for free and open access by the Biological Sciences, School of at DigitalCommons@University of Nebraska - Lincoln. It
has been accepted for inclusion in Dissertations and Theses in Biological Sciences by an authorized administrator of DigitalCommons@University of
Nebraska - Lincoln.
,INVESTIGATION OF BOVINE HERPESVIRUS 1 (BHV-1) ENCODED
INFECTED CELL PROTEIN 0 (BICP0)
by
Natasha N. Gaudreault
A DISSERTATION
Presented to the Faculty of
The Graduate College at the University of Nebraska
In Partial Fulfillment of Requirements
For the Degree of Doctor of Philosophy
Major: Biological Sciences
(Microbiology and Molecular Biology)
Under the Supervision of Professor Clinton Jones
Lincoln, Nebraska
May, 2011
, INVESTIGATION OF BOVINE HERPESVIRUS 1 (BHV-1) ENCODED
INFECTED CELL PROTEIN 0 (BICP0)
Natasha N. Gaudreault, Ph.D.
University of Nebraska, 2011
Advisor: Clinton Jones
Bovine herpesvirus 1 (BHV-1) is a significant pathogen of cattle. Following
acute infection, BHV-1 establishes a latent infection that persists for the life of the
infected host. Stress induced factors cause the virus to reactivate from latency, resulting
in virus transmission and transient immune suppression. BHV-1 encoded bICP0 is
expressed early and constitutively throughout productive infection. bICP0 is critical for
efficient viral replication, virulence, and reactivation in cattle because it stimulates viral
transcription and interferes with innate immune responses. bICP0 potentially interacts
with a variety of proteins to activate viral gene expression and inhibit innate antiviral
defenses. bICP0 localizes to promyelocytic leukemia (PML) protein-containing nuclear
domains, which are associated with antiviral activity and commonly targeted for
disruption by a wide variety of viruses. The zinc RING finger motif within bICP0 plays
a critical role in the biological functions of bICP0, and possesses intrinsic E3 ubiquitin
ligase activity that is important for polyubiquitination and subsequent degradation of
proteins.
Results from these studies demonstrated mutations within the zinc RING finger
increased bICP0 protein levels, presumably due to disruption of the ability of bICP0 to
induce its own ubiquitination. Sequences at its C-terminus are also important for
, regulating the half-life of bICP0. BHV-1 infection and bICP0 expression alone reduced
PML protein levels. Unexpectedly, bICP0 mutants that localized primarily in the
cytoplasm also induced PML degradation. bICP0 was readily detected in the cytoplasm
of low passage bovine cells at later times post infection, suggesting bICP0 induces
degradation of cytoplasmic isoforms of PML to promote viral replication. Identification
of bICP0-interacting proteins was also investigated to further elucidate the mechanisms
underlying bICP0 functions. The ability of BHV-1 and a bICP0 zinc RING finger mutant
to grow in oncogenic cells was also examined to determine if defects in viral growth of
the mutant could be relieved in cells with potential defects in their interferon response.
Collectively, studies presented in this dissertation determine that nuclear and cytoplasmic
bICP0 have functions that promote productive infection.
DigitalCommons@University of Nebraska - Lincoln
Dissertations and Theses in Biological Sciences Biological Sciences, School of
5-2011
Investigation of Bovine Herpesvirus 1 (BHV-1)
Encoded Infected Cell Protein 0 (bICP0)
Natasha N. Gaudreault
University of Nebraska-Lincoln,
Follow this and additional works at: http://digitalcommons.unl.edu/bioscidiss
Part of the Laboratory and Basic Science Research Commons, and the Virology Commons
Gaudreault, Natasha N., "Investigation of Bovine Herpesvirus 1 (BHV-1) Encoded Infected Cell Protein 0 (bICP0)" (2011).
Dissertations and Theses in Biological Sciences. 26.
http://digitalcommons.unl.edu/bioscidiss/26
This Article is brought to you for free and open access by the Biological Sciences, School of at DigitalCommons@University of Nebraska - Lincoln. It
has been accepted for inclusion in Dissertations and Theses in Biological Sciences by an authorized administrator of DigitalCommons@University of
Nebraska - Lincoln.
,INVESTIGATION OF BOVINE HERPESVIRUS 1 (BHV-1) ENCODED
INFECTED CELL PROTEIN 0 (BICP0)
by
Natasha N. Gaudreault
A DISSERTATION
Presented to the Faculty of
The Graduate College at the University of Nebraska
In Partial Fulfillment of Requirements
For the Degree of Doctor of Philosophy
Major: Biological Sciences
(Microbiology and Molecular Biology)
Under the Supervision of Professor Clinton Jones
Lincoln, Nebraska
May, 2011
, INVESTIGATION OF BOVINE HERPESVIRUS 1 (BHV-1) ENCODED
INFECTED CELL PROTEIN 0 (BICP0)
Natasha N. Gaudreault, Ph.D.
University of Nebraska, 2011
Advisor: Clinton Jones
Bovine herpesvirus 1 (BHV-1) is a significant pathogen of cattle. Following
acute infection, BHV-1 establishes a latent infection that persists for the life of the
infected host. Stress induced factors cause the virus to reactivate from latency, resulting
in virus transmission and transient immune suppression. BHV-1 encoded bICP0 is
expressed early and constitutively throughout productive infection. bICP0 is critical for
efficient viral replication, virulence, and reactivation in cattle because it stimulates viral
transcription and interferes with innate immune responses. bICP0 potentially interacts
with a variety of proteins to activate viral gene expression and inhibit innate antiviral
defenses. bICP0 localizes to promyelocytic leukemia (PML) protein-containing nuclear
domains, which are associated with antiviral activity and commonly targeted for
disruption by a wide variety of viruses. The zinc RING finger motif within bICP0 plays
a critical role in the biological functions of bICP0, and possesses intrinsic E3 ubiquitin
ligase activity that is important for polyubiquitination and subsequent degradation of
proteins.
Results from these studies demonstrated mutations within the zinc RING finger
increased bICP0 protein levels, presumably due to disruption of the ability of bICP0 to
induce its own ubiquitination. Sequences at its C-terminus are also important for
, regulating the half-life of bICP0. BHV-1 infection and bICP0 expression alone reduced
PML protein levels. Unexpectedly, bICP0 mutants that localized primarily in the
cytoplasm also induced PML degradation. bICP0 was readily detected in the cytoplasm
of low passage bovine cells at later times post infection, suggesting bICP0 induces
degradation of cytoplasmic isoforms of PML to promote viral replication. Identification
of bICP0-interacting proteins was also investigated to further elucidate the mechanisms
underlying bICP0 functions. The ability of BHV-1 and a bICP0 zinc RING finger mutant
to grow in oncogenic cells was also examined to determine if defects in viral growth of
the mutant could be relieved in cells with potential defects in their interferon response.
Collectively, studies presented in this dissertation determine that nuclear and cytoplasmic
bICP0 have functions that promote productive infection.
