In order to add the gene for human insulin to a bacterial plasmid, the DNA molecules have to be "cut" with enzymes called restri
ction endonucleases and then pasted back together with enzymes called DNA ligases. Imagine that during this process, the first five nucleotides of the human insulin gene were accidentally cut out before it was pasted into the bacterial plasmid. What is the most likely outcome if this plasmid was added to bacterial cells?
For production of human insulin protein in bacteria, first the insulin gene needs to be transcribed to corresponding mRNA. This mRNA will be then translated to produce insulin protein. The initial portion of any gene has a promoter sequence. During transcription RNA Polymerase recognizes this promoter sequence to initiate the process.
Here, the gene's first five nucleotides were accidentally cut out so now the promoter sequence has been altered. RNA Polymerase will not be able to recognise it so transcription will not occur. No mRNA will be formed and as a result translation will also not occur and there will be no production of insulin protein.
