Herpes Simplex Virus Type 1: Secretion, Cell Signaling, And Gene Expression
Herpes simplex virus type 1 (HSV-1) replicates in the nucleus and buds through the nuclear membrane to access the cytosol and complete the maturation process. The HSV-1 protein pUL31, along with its binding partner, pUL34, has been previously shown to be required for nucleocapsids to successfully bud through the nuclear membrane. pUL31 is also required for efficient viral DNA synthesis and packaging. After the HSV-1 exits the nucleus, the capsid acquires several accessory proteins (tegument) and finally a mature envelope by budding into vesicles of the trans-Golgi network (TGN). These virion-laden vesicles traffic toward the cell periphery and through cortical actin until ultimately the virion is secreted upon fusion of the TGN vesicle with the plasma membrane. The data presented here reveals new roles for pUL31, as cells infected with a UL31-null virus were delayed for viral gene expression as well as activation of NF[kappa]B and c-Jun N-terminal kinase (JNK) in multiple cell lines. At least one representative from each kinetic class of viral genes was examined at various times post infection. The protein expression defects were not caused by a failure to enter cells, was not rescued by ICP27 expressed in trans and correlated with NF[kappa]B activation. The data shows that these defects were not observed in the absence of the pUL31 binding partner, pUL34, and that while most pUL31 is expressed at late times post infection, low levels are detectable as early as 2 hours post infection. Data presented in this work also demonstrates a role for the actin motor myosin Va in the secretion of HSV-1 virions. Expression of two isoforms of dominant negative myosin Va (DN-myoVa) decreased virion secretion by 5075% as well as significantly decreased surface expression of viral glycoproteins B, M and D. DN-myoVa colocalized with TGN markers and the conformation of native myosin Va in infected cells was altered by 4 hours post infection. These data suggest that myosin Va is involved in the egress of virion-laden TGN vesicles as they transit through cortical actin toward the plasma membrane.
Herpes Simplex Virus; NF kappa B; viral gene expression
Baines, Joel D
Casey, James Wilton; Whittaker, Gary R
Ph. D., Microbiology
Doctor of Philosophy
dissertation or thesis