Recombinant human insulin, produced by bacteria carrying a cloned insulin gene, is now the major form ofinsulin used to treat diabetes. The human insulin gene encodes an mRNA only 333 nucleotides long, but theentire gene spans more than 4000 nucleotides. There are three exons and two introns.
A. If we were to clone this gene directly from the nuclear DNA, bacteria would not be able to express theinsulin protein. Explain why this is true.
B. What technique should be used instead in order to get a functional insulin coding sequence cloned intobacteria? Describe briefly how this technique works.
C. Every cell in the human body has the same DNA, so every cell has an insulin gene. However, in order touse the technique you described in "b," you would have to start with cells from the pancreas, the onlybody cells that actually produce the insulin protein. Why are these the only cells that would work?