From DNA to Organism: A Study in DNA Function for the High School Biology Classroom

Module 4: Yeast and the gene

Lab letter

        Dear Biology Students,

            I understand that your first investigation of the mutant plants went well. Good work! I need more help with my research of the AKT-1 gene. I have been working on the mutation of the gene that causes the phenotype that you observed in class but have a problem. I am not really sure what the mutation does to the organism. I know that some of my plants have it. I know that they do not do well, but do not know why. As any good scientist would, I looked in the scientific literature and found some other researchers that are working on mutants of the gene as well. They suggest that the gene mutation AKT-1 seems to have something to do with the cells interaction with the potassium in its environment, but they are not sure what either. Your job is to try to figure out specifically how the gene mutation affects the organism that carries it.
           You can use a transgenic organism to experiment with this. Remember that a transgenic organism is one that has had DNA from one, or more, other species added to it. I had one of my graduate students isolate the AKT-1 gene mutation, from the mutant plants, and insert it into some yeast cells. Yeast is a good organism to use for DNA research because it is small and grows easily in lab conditions. My suggestion is that you use the attached procedure to test what affect the gene has on the transformed yeast cells.   It would make sense that if the gene has a certain affect on yeast cells, it would do the same thing for Arabidopsis. I sent along a culture of the transformed yeast (with the mutation of the AKT-1 gene) and some wild-type yeast (with the wild type AKT-1 gene) for you to experiment on.
            Try to design an experiment that will explain what e ffect the mutant gene has on the cells ability to survive in environments with different levels of potassium. I have provided some yeast cells with the gene mutation in it and some without. Please report back to me with your findings.

Ionically yours,

Dr. Berkowitz