Analysis of HPV-1 E4 gene expression using epitope-defined antibodies.
Six monoclonal antibodies (mAbs) have been raised against the E4 proteins of HPV-1. Five of these were found to recognize denaturation-resistant epitopes as determined by Western blotting--and their binding sites were identified by determining their reactivity against a panel of bacterial E4--beta-galactosidase fusion proteins which contained progressive deletions at the C-terminal end of the E4 region. The five mAbs were found to bind to four distinct sites. By using these epitope-defined mAbs, along with anti-peptide antibodies raised against putative N- and C-terminal E4 sequences, we have determined the relationships between the eight distinct polypeptides (mol. wt 10/11 kd, 16/17 kd, 21/23 kd and 32/34 kd) previously shown to be expressed from the E4 gene of HPV-1 in productively infected papillomas. The 17 kd E4 polypeptide appears to be the product of a spliced mRNA encoding five amino acids from open reading frame (ORF) E1 joined onto 120 from the E4 ORF. The 16 kd and 10/11 kd proteins, which may be derived from this, lack sequences (approximately 15 and 70 amino acids respectively) encoded by the 5' end of the E4 gene. The 32/34 kd proteins were detected by all antibodies which reacted with the 16/17 kd polypeptides, suggesting that they represent dimers of the latter species. The 21/23 kd polypeptides, however, do not appear to be simple dimers of the 10/11 kd protein as previously predicted, and reacted with antibodies whose epitopes mapped in the N-terminal half of the E4 protein.(ABSTRACT TRUNCATED AT 250 WORDS)
Doorbar
J
J
Department of Cancer Studies, University of Birmingham, UK.
Evans
H S
HS
Coneron
I
I
Crawford
L V
LV
Gallimore
P H
PH
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000378:metabolism; D001666:Binding Sites, Antibody; D000939:Epitopes; D005786:Gene Expression Regulation; D006801:Humans; D009856:Oncogene Proteins, Viral / Q000235:genetics* / Q000276:immunology; D027383:Papillomaviridae / Q000235:genetics* / Q000378:metabolism; D014412:Tumor Virus Infections / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D014860:Warts / Q000378:metabolism
D000911:Antibodies, Monoclonal; D000939:Epitopes; D009856:Oncogene Proteins, Viral; D014764:Viral Proteins; C056651:oncogene protein E4, human papilloma virus type 1