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Biochemistry

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Evaluating Experiments That Test a Translation Defect Hypothesis

BIOCHM-HZ@L7G

Friedreich's ataxia is an autosomal recessive disease that affects the nervous system. Patients experience progressive loss of muscle coordination and can also suffer heart disease, diabetes and scoliosis.

The disease is caused by an intronic trinucleotide repeat expansion in the FXN gene, which encodes the protein frataxin. In Friedreich's ataxia patients there are over 1000 trinucleotide repeats in the FXN gene and levels of frataxin are sharply reduced.

You wish to determine how exactly this trinucleotide repeat expansion affects frataxin protein synthesis.

Which of the following experiments best tests the hypothesis that the trinucleotide repeat expansion results in a defect in translation of the FXN mRNA?

Assume that all proposed experiments are using probes specific for either FXN mRNA or Frataxin protein when relevant.

A

A Northern blot using an intronic probe.

B

A Western blot of whole cell extract.

C

A Western blot of whole cell extract followed by a Northern blot.

D

DNA footprinting.