Question

Eukaryotic genes can be introduced into bacteria by recombinant DNA techniques. If the introduced gene encodes a protein that is also found in bacteria—for example, a universally used glycolysis enzyme—then expression of the eukaryotic gene may produce a protein that functions in the bacterial cell. In an experiment, the entire mouse gene for a glycolysis enzyme, including its promoter, coding regions and termination sequence, is introduced into an E. coli cell that has a mutant gene for the bacterial version of the same enzyme. Even though the mouse enzyme should function in the bacterial cell and restore the cell's ability to perform glycolysis, it does not.

Provide a possible reason why this experiment does not work and propose a solution to overcome the problem you suggest.

Answer 1

Given information,
A eukaryotic gene coding for a glycolytic enzyme is cloned into a bacterial host that is mutant for the corresponding enzyme. However, the mutant phenotype is not complemented.

Plausible reasons:
1. It should be noted that the protein function may be conserved. However, the cis-elements required for their expression may be quite different. i.e. The eukaryotic promoter may not be recognized by the host polymerase.
2. The eukaryotic gene might contain introns that cannot be removed by the prokaryotic host i.e. splicing is absent in prokaryotes.
3. Even if the transcription occurs, the translation machinery might require specific cis-elements to synthesize the protein.

Please provide a positive rating.