Characterization and nucleotide sequence of two herpes simplex virus 1 genes whose products modulate alpha-trans-inducing factor-dependent activation of alpha genes

Abstract

Herpes simplex viruses encode a structural protein which induces, in trans, expression of a genes, the first set of genes to be expressed after infection of permissive cells. This protein, designated as the a-trans-inducing factor (a-TIF), maps within the BamHI F fragment, and its gene has been sequenced. In the course of mapping the domain of the oa-TIF gene, it was noted that the intact BamHI fragment was consistently more effective than the complete domain of the a-TIF gene in inducing expression of a genes. Cotransfections of DNA fragments containing an a indicator gene and the a-TIF gene with various regions of the BamHI F DNA fragment revealed that the sequences located 3' to the ot-TIF gene raised the activity of the a-TIF gene to nearly the same level as that of the intact BamHI F fragment. The nucleotide sequence and S1 nuclease mapping analyses revealed the presence of two transcribed open reading frames capable of encoding polypeptides with translated molecular weights of 77,357 and 70,527. To determine whether the effect of these sequences in trans on a-TIF-mediated induction of a genes was due to expression of these genes or competition for transcriptional factors, we constructed plasmids that contained both genes. Into each or both of these genes we inserted, near the translation initiation sites, 14-base-pair linkers carrying translational stop codons (TAG) in all three reading frames. Analyses of these plasmids indicated that the gene encoding the 70,527-molecular-weight polypeptide reduced a-TIF-dependent induction of a genes, whereas the gene encoding the 77,357-molecularweight polypeptide increased this activity. Insertion of the stop codons abolished these activities.

Role of herpes simplex virus type 1 UL46 and UL47 in alpha TIF-mediated transcriptional induction: characterization of three viral deletion mutants

“…In transient-expression assays the gene product of UL46 was able to enhance aTIF-mediated induction of an aTK reporter construct 2to 3-fold, while the gene product of UL47 acted to reduce the levels of aTIF-mediated induction 2.5to 3-fold in the presence or absence of UL46. These results were the first report of additional viral factors involved in a-gene induction, and they predicted the presence of a regulatory gene cluster composed of UL46, UL47, and aTIF (UL48) (33,34).The goals of our current study were to investigate the roles of UL46 and UL47 in the context of the virus to determine whether they are essential for viral growth in cell culture, whether their gene products acted in a fashion consistent with previous observations with a transient-expression system, and to begin to determine the levels of their interaction with aTIF. To this end, we constructed a series of deletion mutants lacking either UL46, UL47, or both.…”

“…Complex formation appears to be mediated through the POU domain present in these proteins, which recognizes an octamer element contained within the a element (gyATGN TAATgarattcyttgnggg) (3,12,18,21,24,36). A recent report suggests that aTIF may drive the formation of multiple protein-DNA complexes containing a POU protein and additional host factors, one of which may be cell type specific (21).Previous work has identified a role for at least two additional viral factors, encoded by HSV-1 UL46 and UL47, in aTIF-dependent transcriptional induction (33,34). In transient-expression assays the gene product of UL46 was able to enhance aTIF-mediated induction of an aTK reporter construct 2to 3-fold, while the gene product of UL47 acted to reduce the levels of aTIF-mediated induction 2.5to 3-fold in the presence or absence of UL46.…”

“…Previous work has identified a role for at least two additional viral factors, encoded by HSV-1 UL46 and UL47, in aTIF-dependent transcriptional induction (33,34). In transient-expression assays the gene product of UL46 was able to enhance aTIF-mediated induction of an aTK reporter construct 2to 3-fold, while the gene product of UL47 acted to reduce the levels of aTIF-mediated induction 2.5to 3-fold in the presence or absence of UL46.…”

Antigenic and protein sequence homology between VP13/14, a herpes simplex virus type 1 tegument protein, and gp10, a glycoprotein of equine herpesvirus 1 and 4

“…The immunological cross-reactivity between the proteins VP13/14 and gplO combined with the homology between the genes UL47 and open reading frame B6 allow identification of UL47 as the gene coding for VP13/14. UL47 (or open reading frame B) has been shown to be an important HSV-1 gene; it decreases the a-trans-inducing factor-dependent induction of a genes (20). A second gene, UL46 (or open reading frame A), adjacent to UL47, has been shown to activate the a-trans-inducing factor, which in itself is present in the same cluster of genes and is coded for by UL48.…”

Identification of the immediate-early products of bovine herpesvirus-1

“…The IE genes are transcribed by host cell ribonucleic add polymerase n (RNApol II) (41). IE transcription occurs without de novo viral protein synthesis (92, 93), is further transactivated by a virion associated polypeptide coded for by the viral genome (12,29,69,117,130,131,134,146,186). IE proteins are required for activation of DE and L genes and also the subsequent downregulation of Aie IE genes themselves (55,63,68,69,116,150,162,170,171,180,182,190,260a, 278).…”