Chapter 21, Problem 21.8PS

Antibody Antipathy. You are working on the protein α-catenin in C. elegans and have produced a monoclonal antibody that recognizes this protein. The normal protein identified by this antibody on Western blots is 104 kDa. You go on to identify a mutant that you think produces no protein at all (geneticists call such mutants “protein null” mutants) because Western blots performed using your antibody with protein from this mutant yield no signal. Later, however, another member of your research group sequences your mutant’s DNA and finds that it contains a nonsense codon that produces an early stop codon. Puzzled by this, he uses a polyclonal antibody to perform another Western blot and finds that a band of 89 kDa is visible. How can you explain your labmate’s result?