| Physical associations of BRCA 1 protein with transcription factors Oct 1 and NF YA , which directly bind to the OCT 1 and CAAT motifs , are established by biotin streptavidin pull down and coimmunoprecipitation assays . ^^^ Such protein interactions are required for interaction of BRCA 1 with the GADD 45 promoter because either immunodepletion of Oct 1 and NF YA proteins or mutations in the OCT 1 and CAAT motifs disrupt BRCA 1 binding to the GADD 45 promoter . ^^^ |