Freshman Seminar: Control of Gene Expression 090:101 Section 52

Presentations:
A very important aspect of scientific research is the presentation of the results. Even the most ground breaking research is useless if other people do not know about it. Most scientific research is reported in written papers and oral presentations. We are therefore going to require that each student present a short research seminar to the instructors and other members of the class. You must also hand in the SIR2::HST1-Translation.doc indicating the positions of the base pair and amino acid mutations in your mutants.

Each student will give individual presentations on their research in the 101 course.

Time:  Presentations should be about 3-4 minutes--no more! You will loose credit by rambling or running overtime, so practice for length.

Monday, Nov. 19, 3:20 PM Waksman, Room 311

Power point files of the presentations and the Sir:Hst1 Translation.doc file indicating the position and changes of your mutations are due to Andrew Vershon by e-mail by 1:00 PM on 11/19 Materials handed in late will affect the final grade.

Attendance is required and absences will significantly affect your grade.

What you include in your presentations is up to you.  However, since we have all performed the same experiments there is no need to talk about methods that you used to conduct the experiments. Keep in mind that each student needs to present their data, so you will only have 3-4 minutes for your presentation.  I suggest that you practice it several times before you come to class on Monday so that you know what you are going to say and that you will complete the talk in the time allotted.

Topics you may want to include in your presentation: 

1. Silencing Data: Show the picture of the gel and explain whether your mutants are defective in silencing of the URA3 reporter gene. Indicate if there were any problems with the assay (bad dilutions or the controls did not run properly) Please label your figures so that the audience knows what are control pates and what is the test plate. Indicate the strains.

2. Repression Data:  Show a picture of the graph of the b-galactosidasae data and explain whether your mutants are defective in repression of the lacZ reporter gene. Indicate if there were any problems with the assay. Please label your figures so that the audience knows what each lane is.

3. Compare Silencing with Repression: Does your repression data agree with your silencing data? Is a mutant defective in both silencing and repression or is it just defective in one but not the other? What would cause this? (Remember there are regions of the Sir2::Hst1 chimera that interact with Sir2 cofactors and other regions that interact with hst1 cofactors). What does it mean if it is not defective in either silencing or repression?

4. Where are your mutants?: Show where your mutants map on the gene. Indicate if a base pair mutation would change the amino acid at that position in the protein or if it would code for the same amino acid (a silent mutation). If it changes an amino acid, is it in the Sir2 region or the Hst1 region? Does this correlate with whether the mutant affects repression or silencing? Is the mutation in a conserved region of the protein? (You can determine this by looking at the multiple sequence alignment using the Cn3D program to view the 1J8F file. Residues in red are highly conserved among different member of this family of proteins.) Where does this mutation lie on the structure of the protein? By clicking the residue in the alignment, the position is shown on the model of the crystal structure. You may want to grab a screen image of this and put it in your presentation.

To do screen captures to make powerpoint images:

On a Mac: Use the <apple>-shift-4 key combination to get a cross haira to highlight the region of the screen you want to capture. This willl save as a picture#.png on your desktop that you can import into Powerpoint

On XP: Use Printscreen to capture the whole screen in the clipboard. This can be pasted into Powerpoint. Use <alt>-Printscreen to capture an image of the window that you are in.

On Vista: Use the Snipping tool. See http://graphicssoft.about.com/od/microsoft/ht/snippingtool.htm for directions