The diagram below depicts a protein-coding gene of a eukaryote. In eukaryotic ce
ID: 51595 • Letter: T
Question
The diagram below depicts a protein-coding gene of a eukaryote. In eukaryotic cells, the gene codes for one protein. The regions of the gene are identified in the boxes as they occur along the template strand of DNA (3'->5'). If you wanted to genetically engineer this gene so that it's protein could be produced in prokaryotic cells (e.g. E. coli), which regions of the gene would you retain in the version of the gene that you would introduce into the prokaryotic cells (other regions, as needed, would be replaced by the appropriate DNA sequences typical of prokaryotic genes)?
CAAT Box - TATA Box - 5'UTR - Exon 1 - Intron 1 - Exon 2 - 3'UTR
Write the regions you would retain here:
Briefly explain your choice here:
Explanation / Answer
Prokaryotes contain specific transcription factors. They bind to specific DNA sequences upstream of the start of operons. Whereas in eukaryotes each gene has its own transcriptional control. Therefore, for expressing an eukaryotic gene in prokaryotes, its sufficient to insert the exons that produce that particular protein. We can retain CAAT Box, TATA Box, intron, and 3'UTR. The role of the TATA Box and CAAT Box would be done by the two short sequences at -10 and -35 positions upstream from the trascription start site. Those positions constitute the promoter sequence in prokaryotes. The -10 region is called the Pribnow box and it contians the nucleotides TATAAT. It is essential for the start of transcription in prokaryotes. Thus, inserting the exon sequence downstream the promoter region in prokaryotes would express the required protein.