Final answer:
A eukaryotic gene regulated by three activator proteins is under transcriptional control, where activators enhance the binding of RNA polymerase to initiate transcription. Eukaryotic regulation is complex and occurs at multiple levels without operon organization.
Step-by-step explanation:
A eukaryotic gene that is regulated by three activator proteins is said to be under transcriptional control. In eukaryotes, gene expression can be regulated at different levels, including epigenetic, transcriptional, post-transcriptional, translational, and post-translational. Unlike prokaryotic gene regulation, eukaryotic genes are not organized into operons and require independent regulation. Specific activator proteins, such as transcription factors, bind to regulatory sequences like the TATA box, GC box, and CAT box or enhancer regions, which help in recruiting RNA polymerase and initiating transcription. These activator proteins play a pivotal role in positive regulation by ensuring that RNA polymerase binds efficiently to the promoters, leading to the transcription of the genes they control.