title: A distinct octamer-binding protein present in malignant melanoma cells.
abstract: The octamer-binding proteins present in HeLa cells, B-cells and malignant melanoma cells were compared by a gel-electrophoresis DNA-binding assay. Using an extract from the malignant melanoma cells a complex was formed using a variety of octamer containing probes that was distinct from those found using either a HeLa or B-cell extract. DNAase 1 footprints and methylation interference patterns of the melanoma-specific octamer-binding protein were indistinguishable from those obtained with the HeLa factor NF-A1, except for preferential binding of the melanoma-specific factor to DNA methylated at two G residues 16 base-pairs 3' to the octamer motif. Competition analyses using a variety of wild-type and mutant probes showed that mutations affecting binding of NF-A1 similarly affected binding of the melanoma octamer-binding factor. These data also revealed the extreme flexibility of the octamer-binding site, with one probe sharing only 4 bases with the 8 base consensus sequence binding efficiently.
authors.affiliation: Marie Curie Research Institute, Oxted, Surrey, UK.
authors.forename: P M
authors.initials: PM
authors.lastname: Cox
authors.forename: S M
authors.initials: SM
authors.lastname: Temperley
authors.forename: H
authors.initials: H
authors.lastname: Kumar
authors.forename: C R
authors.initials: CR
authors.lastname: Goding
mesh_terms: D001402:B-Lymphocytes / Q000032:analysis; D001482:Base Composition; D002460:Cell Line; D015254:DNA Modification Methylases; D004273:DNA, Neoplasm / Q000032:analysis; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics*; D003850:Deoxyribonuclease I; D006367:HeLa Cells; D006801:Humans; D008545:Melanoma / Q000032:analysis / Q000235:genetics*; D015345:Oligonucleotide Probes; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D015345:Oligonucleotide Probes; D015254:DNA Modification Methylases; D003850:Deoxyribonuclease I