Journal of General Virology, Vol 78, 179-188, Copyright © 1997 by Society for General Microbiology
Replacement of the herpes simplex virus type 1 Vmw175 DNA binding domain with its varicella-zoster virus counterpart results in a protein with novel regulatory properties that can support virus growth
JK Tyler, A Orr and RD Everett
MRC Virology Unit, Glasgow, UK.
The alphaherpesviruses encode major immediate early transactivator proteins
that are essential for the expression of later classes of viral genes. We
have previously shown that the extensive sequence similarity between the
herpes simplex virus type 1 (HSV-1) and varicella-zoster virus (VZV)
members of the family (proteins Vmw175 and VZV140k) extends to function,
since a virus which expresses VZV140k in place of Vmw175 is able to grow,
albeit at reduced efficiency. We have also shown that the DNA binding
characteristics of the isolated DNA binding domains of Vmw175 and VZV140k
are related but distinct. In order to assess whether the different DNA
binding properties of the two proteins are responsible for the differences
in their individual transcriptional regulatory functions, we constructed a
plasmid and an HSV-1 virus in which the VZV140k DNA binding domain coding
sequences replace those of Vmw175. The characteristics of the resultant
hybrid protein in transfection assays and during virus infection suggest
that the nature of the DNA binding domain plays a significant role in the
transactivation and repression properties of the Vmw1 75 family of
proteins.
