Oncogene Proteins v-myb/chemistry; Oncogene Proteins v-myb/genetics; Amino Acid Sequence; Animals; Animals, Genetically Modified; Binding Sites/genetics; Breast Neoplasms/genetics; Cell Cycle Proteins/genetics; Conserved Sequence; Drosophila Proteins/chemistry; Drosophila Proteins/genetics; Drosophila Proteins/metabolism; Drosophila melanogaster/genetics; Drosophila melanogaster/metabolism; Evolution, Molecular; Female; Genes, myb; Humans; Male; Molecular Sequence Data; Mutagenesis, Site-Directed; Mutant Proteins/chemistry; Mutant Proteins/genetics; Mutant Proteins/metabolism; Oncogene Proteins v-myb/metabolism; Protein Structure, Tertiary; Repressor Proteins/chemistry; Repressor Proteins/genetics; Repressor Proteins/metabolism; Sequence Homology, Amino Acid; Trans-Activators/genetics