Molecular Biology of the Gene 7th Edition by Richard Losick, James Watson, Michael Levine, Tamara Baker, Alexander Gann

Exercise 6

You want to characterize the developmental expression of the gene in Drosophila melanogaster. You isolate mRNA from embryos and adult flies and perform a northern blot using a labeled DNA probe specific to Gene Z mRNA, a gene required for development. The results are depicted below.

Intrigued, you isolate protein Z from embryos and adult flies and perform a western blot using an antibody against the carboxyl terminus of the protein. The results are depicted below. You are surprised to find a single band of the same molecular weight in both embryos and adult flies.
A. Propose a hypothesis to explain these results.
B. Propose a modification to the western blot experimental strategy that would allow you to test your hypothesis. Assume you have access to any necessary reagents.