scholarly journals DNA Recognition by the Herpes Simplex Virus Transactivator VP16: a Novel DNA-Binding Structure

2001 ◽  
Vol 21 (14) ◽  
pp. 4700-4712 ◽  
Author(s):  
Robert Babb ◽  
C. Chris Huang ◽  
Deborah J. Aufiero ◽  
Winship Herr
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Simplex Virus ◽  
Carboxy Terminal

ABSTRACT Upon infection, the herpes simplex virus (HSV) transcriptional activator VP16 directs the formation of a multiprotein-DNA complex—the VP16-induced complex—with two cellular proteins, the host cell factor HCF-1 and the POU domain transcription factor Oct-1, on TAATGARAT-containing sequences found in the promoters of HSV immediate-early genes. HSV VP16 contains carboxy-terminal sequences important for transcriptional activation and a central conserved core that is important for VP16-induced complex assembly. On its own, VP16 displays little, if any, sequence-specific DNA-binding activity. We show here that, within the VP16-induced complex, however, the VP16 core has an important role in DNA binding. Mutation of basic residues on the surface of the VP16 core reveals a novel DNA-binding surface with essential residues which are conserved among VP16 orthologs. These results illuminate how, through association with DNA, VP16 is able to interpret cis-regulatory signals in the DNA to direct the assembly of a multiprotein-DNA transcriptional regulatory complex.

scholarly journals Stabilization but Not the Transcriptional Activity of Herpes Simplex Virus VP16-Induced Complexes Is Evolutionarily Conserved among HCF Family Members

2001 ◽  
Vol 75 (24) ◽  
pp. 12402-12411 ◽  
Author(s):  
Soyoung Lee ◽  
Winship Herr
Keyword(s):  
Cell Proliferation ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Transcriptional Activation ◽  
Early Gene ◽  
Activation Of Transcription ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Simplex Virus

ABSTRACT The human herpes simplex virus (HSV) protein VP16 induces formation of a transcriptional regulatory complex with two cellular factors—the POU homeodomain transcription factor Oct-1 and the cell proliferation factor HCF-1—to activate viral immediate-early-gene transcription. Although the cellular role of Oct-1 in transcription is relatively well understood, the cellular role of HCF-1 in cell proliferation is enigmatic. HCF-1 and the related protein HCF-2 form an HCF protein family in humans that is related to a Caenorhabditis elegans homolog called CeHCF. In this study, we show that all three proteins can promote VP16-induced-complex formation, indicating that VP16 targets a highly conserved function of HCF proteins. The resulting VP16-induced complexes, however, display different transcriptional activities. In contrast to HCF-1 and CeHCF, HCF-2 fails to support VP16 activation of transcription effectively. These results suggest that, along with HCF-1, HCF-2 could have a role, albeit probably a different role, in HSV infection. CeHCF can mimic HCF-1 for both association with viral and cellular proteins and transcriptional activation, suggesting that the function(s) of HCF-1 targeted by VP16 has been highly conserved throughout metazoan evolution.

scholarly journals DNA Binding Activity of the Herpes Simplex Virus Type 1 Origin Binding Protein, UL9, Can Be Modulated by Sequences in the N Terminus: Correlation between Transdominance and DNA Binding

2006 ◽  
Vol 80 (9) ◽  
pp. 4491-4500 ◽  
Author(s):  
Soma Chattopadhyay ◽  
Sandra K. Weller
Keyword(s):  
Herpes Simplex ◽  
Dna Binding ◽  
Binding Activity ◽  
Plaque Formation ◽  
Dna Binding Domain ◽  
Dna Binding Activity ◽  
Origin Binding Protein ◽  
N Terminus ◽  
Simplex Virus

ABSTRACT UL9, the origin binding protein of herpes simplex virus type 1, is a member of the SF2 family of helicases. Cotransfection of cells with infectious viral DNA and plasmids expressing either full-length UL9 or the C-terminal DNA binding domain alone results in the drastic inhibition of plaque formation which can be partially relieved by an insertion mutant lacking DNA binding activity. In this work, C-terminally truncated mutants which terminate at or near residue 359 were shown to potentiate plaque formation, while other C-terminal truncations were inhibitory. Thus, residues in the N-terminal region appear to regulate the inhibitory properties of UL9. To identify which residues were involved in this regulation, a series of N-terminally truncated mutants were constructed which contain the DNA binding domain and various N-terminal extensions. Mutants whose N terminus is either at residue 494 or 535 were able to bind the origin efficiently and were inhibitory to plaque formation, whereas constructs whose N terminus is at residue 304 or 394 were defective in origin binding activity and were able to relieve inhibition. Since UL9 is required for viral infection at early but not late times and is inhibitory to infection when overexpressed, we propose that the DNA binding activities of UL9 are regulated during infection. For infection to proceed, UL9 may need to switch from a DNA binding to a non-DNA binding mode, and we suggest that sequences residing in the N terminus play a role in this switch.

scholarly journals Interdigitated residues within a small region of VP16 interact with Oct-1, HCF, and DNA.

1997 ◽  
Vol 17 (7) ◽  
pp. 3937-3946 ◽  
Author(s):  
J S Lai ◽  
W Herr
Keyword(s):  
Amino Acids ◽  
Dna Binding ◽  
Transcriptional Activation ◽  
Small Region ◽  
Transcriptional Activation Domain ◽  
Amino Acid Region ◽  
Transcriptional Regulatory ◽  
Mat Alpha2 ◽  
Simplex Virus ◽  
Carboxy Terminal

Upon infection, the herpes simplex virus (HSV) activator of immediate-early (IE) gene transcription VP16 forms a multiprotein-DNA complex with two cellular proteins, Oct-1 and HCF. First, VP16 associates with HCF independently of DNA, and this association stimulates subsequent association with Oct-1 on the DNA target of VP16 activation, the TAATGARAT motif found in HSV IE promoters. We have analyzed the involvement of VP16 residues lying near the carboxy-terminal transcriptional activation domain of VP16 in associating with HCF, Oct-1, and DNA. To assay VP16 association with HCF, we developed an electrophoretic mobility retardation assay in which HCF is used to retard the mobility of a hybrid VP16-GAL4 DNA-binding domain fusion protein bound to a GAL4 DNA-binding site. Analysis of an extensive set of individual and combined alanine substitutions over a 61-amino-acid region of VP16 shows that, even within a region as small as 13 amino acids, there are separate residues involved in association with either HCF, DNA, or Oct-1 bound to DNA; indeed, of two immediately adjacent amino acids in VP16, one is important for DNA binding and the other is important for HCF binding. These results suggest that a small region in VP16 is important for linking in close juxtaposition the four components of the VP16-induced complex and support the hypothesis that the structure of the Oct-1-VP16 interaction in this complex is similar to that formed by the yeast transcriptional regulatory proteins MATa1 and MAT alpha2. We propose that HCF stabilizes this Oct-1-VP16 interaction.

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