You Expect That a Mutation in E

Multiple Choice

You expect that a mutation in E. coli that was recently isolated results in loss of enzyme R activity. In looking for the gene you find comparable sequences. Using an in vitro transcription translation system, you use the gene obtained from the mutant as well as a wild type E. coli as a control. Following protein isolation and gel electrophoresis, you observe that the wild type E. coli produces a protein that is 35K in size, corresponding to enzyme R. However, the mutant strain produces a protein that is 25K in size. What does this information suggest?

A) A missense mutation has occurred, resulting in a truncated, nonfunctional product in the mutant.
B) A nonsense mutation has occurred, resulting in a truncated, nonfunctional product in the mutant.
C) A large addition has occurred in the wild type strain, such that approximately 35 tandem repeats of this gene are present and are biologically active.
D) all of the above
E) Not enough information is given.