title: Interactions of a Rel protein with its inhibitor.
abstract: Cactus, a Drosophila homologue of I kappa B, binds to and inhibits Dorsal, a homologue of the p50 and p65 components of NF-kappa B. We describe experiments in yeast with various Dorsal and Cactus derivatives showing that Cactus blocks the DNA binding and nuclear localization functions of Dorsal. In contrast, Dorsal's transcriptional activating region is functional in the Dorsal-Cactus complex. We identify two Dorsal mutants, Dorsal C233R and Dorsal S234P, that escape Cactus inhibition in vivo, and we show that these mutants fail to interact with Cactus in vitro. From this and data of others, we identify the likely surface of Dorsal that binds Cactus. We also describe a modified PCR mutagenesis procedure, easier to use than conventional methods, that produces a library of high complexity.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins; D004926:Escherichia coli; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000737:chemistry / Q000378:metabolism*; D009687:Nuclear Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D010750:Phosphoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D051996:Transcription Factor RelA; D014157:Transcription Factors; D001616:beta-Galactosidase / Q000032:analysis / Q000096:biosynthesis
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D016328:NF-kappa B; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D051996:Transcription Factor RelA; D014157:Transcription Factors; C062236:dl protein, Drosophila; C077938:cact protein, Drosophila; D001616:beta-Galactosidase