Question

Dr A. Rachnid plans to express the gene for spider silk in E. coli(to make her fortune).  The gene has three exons.

1. Draw the spider silk gene, labelling introns and exons and showing where both transcription and translation start and stop. (3 marks)
2. Explain how Dr Rachnid should modify the spider silk gene so that it can be expressed in E. coli.  (2 marks)
3. She makes the modifications and all seems to be going well until several workers in her spider silk production facility develop cancer. Further investigation reveals that this is because a by-product of spider silk activates retrotransposons, resulting in a high frequency of retrotransposon-induced mutations.  Mutations in both p53 and mdm2 cause cancer.  For each gene, suggest a mechanism by which a retrotransposon could alter the expression of the gene in such a way as to cause cancer.  Explain how the retrotransposon affects expression of the gene and why this leads to an increased risk of cancer.     (3 marks)
4. Dr Dimwhitt is called in for advice and suggests that factory workers could be given an inhibitor of retrotransposon movement. He suggests an inhibitor of either RNA polymerase or reverse transcriptase as both are required for retrotransposon movement.  Is he correct?  Would inhibiting either of these solve the problem? Explain your answer. (2 marks)

Answer 1

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Dr Dimwit is correct in his advice because both Reverse transcriptase and RNA polymerase are integral part of retrotransposon movement in our body .

If both of these enzymes are inhibited then retrotransposon elements can not get into our genome replicate and translate .