To express red fluorescent protein in bacteria, which plasmid components are needed?

To express red fluorescent protein in bacteria, which plasmid components are needed?

• A. Origin of replication, promoter, gene of interest (rfp)
• B. Origin of replication, promoter, gene of interest (rfp), and antibiotic resistance
• C. Promoter, gene of interest (rfp) only
• D. Origin of replication and antibiotic resistance

Answer: (B)

Achieving expression of a protein from a plasmid in bacteria requires a plasmid that can persist in the cells, a way to turn transcription on, the actual coding sequence for the protein, and a method to identify cells that carry the plasmid. The origin of replication lets the plasmid replicate inside the bacterial host so it isn’t lost over time. The promoter provides the signal that initiates transcription, controlling when and how much red fluorescent protein is made. The gene of interest (rfp) is the blueprint that encodes the red fluorescent protein. The antibiotic resistance gene serves as a selectable marker, allowing you to grow only those bacteria that have taken up the plasmid in the presence of the antibiotic. Without any one of these elements, expression or selection would fail: missing an origin means the plasmid won’t be maintained; missing a promoter means no transcription; missing the gene means no red fluorescent protein; missing a selectable marker makes it hard to identify the bacteria that carry the plasmid.

Achieving expression of a protein from a plasmid in bacteria requires a plasmid that can persist in the cells, a way to turn transcription on, the actual coding sequence for the protein, and a method to identify cells that carry the plasmid. The origin of replication lets the plasmid replicate inside the bacterial host so it isn’t lost over time. The promoter provides the signal that initiates transcription, controlling when and how much red fluorescent protein is made. The gene of interest (rfp) is the blueprint that encodes the red fluorescent protein. The antibiotic resistance gene serves as a selectable marker, allowing you to grow only those bacteria that have taken up the plasmid in the presence of the antibiotic. Without any one of these elements, expression or selection would fail: missing an origin means the plasmid won’t be maintained; missing a promoter means no transcription; missing the gene means no red fluorescent protein; missing a selectable marker makes it hard to identify the bacteria that carry the plasmid.