Biomaterial Database

The oct-1 homeo domain contacts only part of the octamer sequence and full oct-1 DNA-binding activity requires the POU-specific domain. 1990

C P Verrijzer, and A J Kal, and P C van der Vliet

Laboratory for Physiological Chemistry, University of Utrecht, The Netherlands.

The ubiquitous octamer-binding protein oct-1 contains a POU domain required for DNA binding, which can be subdivided into a POU-specific domain and a POU homeo domain. We have overproduced the POU domain and the POU homeo domain in a vaccinia expression system, purified both polypeptides to near homogeneity, and compared their DNA-binding properties. In contrast to the POU domain, the homeo domain protects only part of the octamer sequence in the Ad2 origin against breakdown by DNase I or hydroxyl radicals. Analysis of purine contacts by DMS and DEPC interference assays shows that the Ad2 octamer can be divided into two regions: one that is recognized both by the POU domain and the homeo domain in an identical fashion, and one that is only recognized by the POU domain. This suggests that the POU-specific domain is responsible for the additional contacts located at one side of the octamer. In agreement with this, mutating the first 3 nucleotides (ATG) of the octamer affected binding by the POU domain but not by the homeo domain. The apparent binding affinities to different octamer sites were compared. The homeo domain binds 600-fold less efficiently to the canonical octamer sequence (ATGCAAAT) than the POU domain. The difference is only sevenfold for the Ad2 octamer, whereas both Kd values are almost identical for the HSV ICP4 TAATGARAT motif. Both the POU and homeo domains recognize target sequences for mammalian homeo box proteins. We conclude that the octamer can act as a bipartite recognition sequence for oct-1 and that the POU-specific domain contributes to the binding affinity, as well as to the specificity, by providing additional contacts.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009690	Nucleic Acid Conformation	The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.	DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D009710	Nucleotide Mapping	Two-dimensional separation and analysis of nucleotides.	Fingerprints, Nucleotide,Fingerprint, Nucleotide,Mapping, Nucleotide,Mappings, Nucleotide,Nucleotide Fingerprint,Nucleotide Fingerprints,Nucleotide Mappings
D002467	Cell Nucleus	Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D003850	Deoxyribonuclease I	An enzyme capable of hydrolyzing highly polymerized DNA by splitting phosphodiester linkages, preferentially adjacent to a pyrimidine nucleotide. This catalyzes endonucleolytic cleavage of DNA yielding 5'-phosphodi- and oligonucleotide end-products. The enzyme has a preference for double-stranded DNA.	DNase I,Streptodornase,DNA Endonuclease,DNA Nicking Enzyme,DNAase I,Dornavac,Endonuclease I,Nickase,Pancreatic DNase,T4-Endonuclease II,T7-Endonuclease I,Thymonuclease,DNase, Pancreatic,Endonuclease, DNA,T4 Endonuclease II,T7 Endonuclease I
D004268	DNA-Binding Proteins	Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.	DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D005609	Free Radicals	Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. Free radicals include reactive oxygen and nitrogen species (RONS). They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.	Free Radical
D005801	Genes, Homeobox	Genes that encode highly conserved TRANSCRIPTION FACTORS that control positional identity of cells (BODY PATTERNING) and MORPHOGENESIS throughout development. Their sequences contain a 180 nucleotide sequence designated the homeobox, so called because mutations of these genes often results in homeotic transformations, in which one body structure replaces another. The proteins encoded by homeobox genes are called HOMEODOMAIN PROTEINS.	Genes, Homeotic,Homeobox Sequence,Homeotic Genes,Genes, Homeo Box,Homeo Box,Homeo Box Sequence,Homeo Boxes,Homeobox,Homeoboxes,Hox Genes,Sequence, Homeo Box,Gene, Homeo Box,Gene, Homeobox,Gene, Homeotic,Gene, Hox,Genes, Hox,Homeo Box Gene,Homeo Box Genes,Homeo Box Sequences,Homeobox Gene,Homeobox Genes,Homeobox Sequences,Homeotic Gene,Hox Gene,Sequence, Homeobox,Sequences, Homeo Box,Sequences, Homeobox