Abstract
Homeo domain proteins exhibit distinct biological functions with specificities that cannot be predicted by their sequence specificities for binding DNA. Recognition of the surface of the Oct-1 POU homeo domain provides a general model for the contribution of selective protein-protein interactions to the functional specificity of the homeo domain family of factors. The assembly of Oct-1 into a multiprotein complex on the herpes simplex virus α/IE enhancer is specified by the interactions of its homeo domain with ancillary factors. This complex (C1 complex) is composed of the viral αTIF protein (VP16), Oct-1, and one additional cellular component, the C1 factor. Variants of the Oct-1 POU homeo domain were generated by site-directed mutagenesis, which altered the residues predicted to form the exposed surface of the domain-DNA complex. Proteins with single amino acid substitutions on the surface of either helix 1 or 2 of the Oct-1 POU homeo domain had decreased abilities to form the C1 complex. The behavior of these mutants in a cooperative DNA-binding assay with αTIF suggested that the Oct-1 POU homeo domain is principally recognized by αTIF in the C1 complex. The preferential recognition of Oct-1 over the closely related Oct-2 protein is critically influenced by a single residue on the surface of helix 1 because the introduction of this residue into the Oct-2 POU homeo domain significantly enhanced its ability to form a C1 complex.
Original language | English (US) |
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Pages (from-to) | 2047-2057 |
Number of pages | 11 |
Journal | Genes and Development |
Volume | 6 |
Issue number | 11 |
DOIs | |
State | Published - Nov 1992 |
Externally published | Yes |
Keywords
- Herpes simplex virus
- Homeo domain
- Octamer-binding proteins
- POU domain
- Protein-protein interactions
- αTIF(VP16)
ASJC Scopus subject areas
- Genetics
- Developmental Biology