Transcriptional co-regulators interact specifically and non-covalently with one or multiple DNA-binding transcription factors (TFs) to either activate or repress the transcription of specific genes. The transcriptional co-activator p300 is a histone acetyltransferase that is typically recruited to transcriptional enhancer and interacts with transcription factors and regulates gene expression. 
Signosis has developed TF-Coregulator p300 Interaction Plate Array Assay I, allowing for high throughput studying of co-regulator interaction networks with 48 different TFs.