Final answer:
Eukaryotic RNA polymerase III promoters utilize transcription factors to form an initiation complex for transcription. These factors are essential for RNA pol III to recognize and bind to specific promoter DNA sequences, setting the stage for gene expression.
Step-by-step explanation:
The assembly factors for RNA polymerase III (RNA pol III) promoters in eukaryotic cells include various transcription factors that are essential for the initiation of transcription. Unlike the simpler system in prokaryotes where a sigma factor aids in promoter recognition, eukaryotes rely on a collection of basal transcription factors that help position RNA pol III at the start of a gene. While RNA polymerase II uses factors designated as TFIIA-J, the factors for RNA polymerase III are less complex but follow a similar theme for recruitment to the promoter DNA sequence. The promoter structures for RNA polymerase I and III genes share some common features but have unique elements as well. For instance, genes transcribed by RNA polymerase III may contain upstream promoters or internal promoters. Basal factors are crucial as they form an initiation complex with RNA polymerase to commence transcription.