Final answer:
The DPE, or downstream promoter element, is the transcribed region element that is common in Drosophila but hard to find in human genes. Drosophila genes often have both a TATA box and a DPE, whereas human gene regulation involves less frequent use of the DPE.
Step-by-step explanation:
The element located within the transcribed region and common in Drosophila, but difficult to find in human genes, is the DPE (downstream promoter element). Unlike the TATA box, which is found upstream of the transcriptional start site, the DPE is found downstream. The TATA box is a well-characterized DNA sequence (5'-TATAAA-3') within the core promoter region and is situated about 25 to 35 bases upstream of the transcription start site. It serves as the binding site for several transcription factors that are involved in the initiation of transcription by RNA polymerase II.
Drosophila genes often contain both a TATA box and a DPE, which interacts with the transcriptional machinery to regulate gene expression. However, in human genes, the DPE is not as commonly found. The DPE is recognized by specific transcription factors and plays a critical role in the transcription initiation of certain genes in Drosophila. This difference between Drosophila and human gene regulation emphasizes the diversity of promoter architectures across species.