Final answer:
A basal transcription factor like TFIID binds to a gene's promoter first and helps recruit other transcription factors, forming a complex that enables RNA polymerase II to initiate transcription.
Step-by-step explanation:
A transcription factor that binds to a gene first and facilitates the binding of other transcription factors is known as a basal transcription factor. These factors include TFIID, which is one of the first to bind to the promoter region of a gene, specifically to the TATA box sequence.
TFIID then recruits additional transcription factors to organize the formation of a preinitiation complex. This complex serves as a platform for RNA polymerase II to initiate transcription. Importantly, enhancer regions can be bound by specific transcription factors to significantly increase or decrease the transcription of a target gene.