26malik
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Cloning of a new eukaryotic gene was followed by insertion and ligation of the gene in an expression vector. The protein translated from this gene was then studied on a western blot, and probed with 32P-DNA, yielding a positive result. These findings eliminate which of the following substances as a candidate for the likely gene product?
A. CREB
B. Protein kinase A
C. RNA polymerase
D. SP-1
E. Steroid receptor
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| doc179
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B
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| doc179
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aisha has also posted the same Q a couple of hrs ago.
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| 26malik
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The correct answer is B.
The stem suggests that the protein isolated is a DNA-binding protein, since the probing was done with a DNA probe and not an antibody. Protein kinase A is an enzyme that phosphorylates other proteins rather than interacting with DNA, and therefore would give a negative result with a DNA probe. Protein kinase A is a cAMP-dependent kinase.
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| scion
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agree B. This assay measures DNA binding activity of a protein. Transcription factors, steroid receptor and RNA polymerase, but not PKA, are all able to bind DNA.
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