Final answer:
Eukaryotic promoters vary with the type of RNA polymerase, and do not strictly require all four core promoter elements as the essential promoter elements can differ, such as the TATA box for RNA polymerase II and GC-rich sequences for RNA polymerase I.
Step-by-step explanation:
No, eukaryotic promoters do not always require all four core promoter elements (-35, -30, start site, and +30) in order for RNA polymerase to initiate transcription. In eukaryotes, the transcription initiation complex formation is more complex and requires a set of core promoter elements which vary between different types of RNA polymerase (I, II, and III). For instance, RNA polymerase II typically relies on a TATA box located at about -30, but additional promoter elements such as CAAT and GC boxes can enhance the efficiency of transcription initiation.
Each RNA polymerase in eukaryotic cells recognizes different conserved promoter elements. For example, RNA polymerase I responds to two GC-rich promoter sequences in the -45 to +20 region, while RNA polymerase III may have promoters within the genes themselves or upstream. All eukaryotic RNA polymerases require transcription factors to assist in the recognition and binding to the promoter regions, with RNA polymerase II requiring additional sequences like the TATA box, CAAT box, and GC-rich boxes for regulation and recruitment of the necessary transcription machinery.