Final answer:
Proteins that bind to DNA to facilitate RNA synthesis are known as transcription factors, including both basal transcription factors and regulatory proteins like activators and repressors.
Step-by-step explanation:
Proteins that bind to DNA and facilitate RNA synthesis by recruiting RNA polymerase to the promoter are collectively called transcription factors. These important proteins play a crucial role in the regulation of gene expression. In prokaryotes, a simple sigma factor aids the RNA polymerase in binding to the promoter. However, in eukaryotic cells, the process is more complex and involves several types of transcription factors, including basal transcription factors such as TFII that help in the assembly of the initiation complex on the promoter region. This complex recruitment is necessary for RNA polymerase II to initiate transcription. Additionally, activator and repressor proteins modulate the efficiency and rate of transcription process by either enhancing or inhibiting the binding of RNA polymerase and other transcription factors to promoter DNA.