How can a human gene be expressed in bacteria?

How can a human gene be expressed in bacteria?

• A. By exposing to high temperature
• B. By mutating the gene
• C. By placing the gene under a bacterial promoter on a plasmid
• D. By removing introns from the gene

Answer: (C)

Expressing a human gene in bacteria requires a DNA construct that bacteria can read and maintain. Bacteria use promoters that are recognized by their RNA polymerase to start transcription, and a plasmid serves as the vehicle to carry the gene into the bacterial cell and to replicate. Placing the human gene downstream of a bacterial promoter on a plasmid provides both the transcriptional signal and the means to produce the mRNA and, ultimately, protein inside the bacteria. In practice, the gene is often used in a form without introns (cDNA) because bacteria lack the machinery to splice introns, but the essential step for expression is supplying a bacterial promoter on a plasmid. Exposing cells to high temperature does not create the necessary transcriptional control, mutating the gene does not enable expression, and removing introns alone does not provide the promoter and vector required for expression.

Expressing a human gene in bacteria requires a DNA construct that bacteria can read and maintain. Bacteria use promoters that are recognized by their RNA polymerase to start transcription, and a plasmid serves as the vehicle to carry the gene into the bacterial cell and to replicate. Placing the human gene downstream of a bacterial promoter on a plasmid provides both the transcriptional signal and the means to produce the mRNA and, ultimately, protein inside the bacteria. In practice, the gene is often used in a form without introns (cDNA) because bacteria lack the machinery to splice introns, but the essential step for expression is supplying a bacterial promoter on a plasmid. Exposing cells to high temperature does not create the necessary transcriptional control, mutating the gene does not enable expression, and removing introns alone does not provide the promoter and vector required for expression.