Question

1. You want to immunolabel a low abundance expressed transmembrane receptor in the plasma membrane in epithelial cells. Describe the process you would do to label by immune-labeling with fluorescence this protein? Be specific in your answer 3 pts

2.

Based on your knowledge of fluorophores and reading of the spectra of dyes, answer this question. You immunolabeled two proteins found close together in muscle fiber sarcomeres by immunofluorescence and a toxin conjugated fluorophore. You need to next show the proteins in the specimen as distinct proteins using fluorescence microscopy. Therefore, from the list of fluorophores below, choose the best two fluorescent tags to use in combination for fluorescence microscopy (circle your two choices). There are several fluorophores to choose from to answer this question, but you want the best combination and should consider the additional issues on fluorophore use in fluorescence microscopy covered in lecture. 4 pts

1. Fluorescein isothiocyanate
2. Aequorin
3. Alexa 345
4. Tetramethylrhodamine
5. Acridine Orange
6. Alexa 488
7. DAPI

*Explain why you chose the two fluorophores to work best together in combination to label the specimen.

Answer 1