Question

After decades of work, an old classmate of yours has isolated a small amount of attractase, an enzyme producing a powerful human pheromone, from hair samples of Hollywood celebrities. To produce attractase for his personal use, he isolated the human attractase gene directly from a human genomic DNA library. Your friend then inserted the gene into a bacterial expression vector and then introduced the recombinant plasmid into an appropriate E. coli strain for expression of the protein with a fusion tag. To your friend's dismay no attractase fusion protein was produced in the cells.

What are TWO potential explanations for this failure? Briefly justify your answers.

Organize your answers as follows:

Reason 1 (one sentence):

Reason 2 (one sentence):

Answer 1

Reason 1:- Since, the attractase gene which he cloned contain introns also as it was isolated from Genomic DNA library. Thus, the introns are not excised out in bacteria due to lack of splicing machinery can lead to the no protein production.

Reason 2:- Attractase gene may contain rare codons and we know that these rare codon are not recognised in bacterial system because they don't have cognate tRNA. Thus, if the bacterial cell while translating encounter the rare codon, the translation will hault and no protein will be produced.

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