A graduate student is studying mutant hamster pancreatic cells. The students loc
ID: 261659 • Letter: A
Question
A graduate student is studying mutant hamster pancreatic cells. The students localizes protein X to the interior (cytosol) of these cells and determines that the protein contains disulfide bonds. This same protein in normal cells is also localized to the interior of the cell (cytosol) but contains no disulfide bonds. In a separate experiment using the mutant cells, radiolabeled lysine was added and remained localized outside the cells. When radiolabeled lysine was added to normal hamster cells, it was localized to the interior of the cells. When radiolabeled glutamate was added to the interior of the mutant cells, a higher than normal concentration of radiolabeled gamma-Glu-Cys was detected. In a separate experiment a lower than normal concentration of leukotriene C4 was detected. Explain all of these results. Design an experiment to test your hypothesis. 3.Explanation / Answer
Leukotrienes C4 is also called as cysteinal leukotriene . The presence of disulphide bond in mutant shows that this leukotriene C4 synthetase is mutated. Its main function is to translocate lipids and formation of lekotriene C4 by attaching glutathione. It cannot translocate Glu - cys and that is why glu-cys is present inside the cell in higher amounts . The leuotriene C4 synthetase cannot translocate lys and thus it remains outside. By using Northern blot , the mRNA for leukotriene synthetase can be measured in hamsters or in rats. If the quantity of mRNA detected is expressed in normal levels then leukotriene c4 will also be normal . If it is expressed less then leuotriene c4 will also be less and thus the cell has mutated leukotriene synthetase