Below is a list of the picture files (in both png and tiff format) of your silencing plate assays. The SD-leu (growth control) plate is on the left and the SD-leu+ 5FOA (silencing assay) plate is on the right. The yeast strain contains the URA3 reporter gene integrated at the telomere. In a SIR2 (wild type strain) the reporter is transcriptionally silenced and so the yeast strains are able to grow on plates with the drug 5-FOA, which kills cells that express URA3.  In a sir2 mutant strain the URA3 gene is no longer silenced and so these cells are killed on 5-FOA plates. 

If you set up the plates according to the lab directions:

A) The top row is the pRS425 (blank) control, which should not silenced.

B) The second row is pJM447 (wild type HST1::SIR2) control, which should be silenced.

C) and D) two of your HST1::SIR2 mutant plasmids into the sir2 strain with the URA3 reporter. 

To analyze your results,

1) Compare the growth on the SD-leu control plate. Do each of your samples have the same number of cells? That is, do you see roughly the same number of cells for a given dilution (1, 2, 3, 4 or 5) for each strain? If there are large differences (i.e growth in spot 5 for one strain but no growth in spot 3 for another) then you need to take this into account when examining the results on the SD-leu+5FOA plate. If each strain has roughly the same number of cells for a given dilution, then that indicates that the same number cells were plated on the test plate.

2) Compare the growth on the SD-leu+5FOA test plate. Do you observe equal growth for all your strains? If there is no growth on the 5FOA plate but lots of growth on the control plate, then that would indicate the URA3 is not silenced. However if there is roughly the same level of growth on the 5FOA and control plates, then that indicates the URA3 reporter gene is silenced.

To download the files right-click (control-click for Mac users) on the file you wish to download and save it to your computer.

ab.png
ab.tif
ag.png
ag.tif
db.png
db.tif
em.png
em.tif
jl.png
jl.tif
jma.png
jma.tif
jr.png
jr.tif
kb.png
kb.tif
km.png
km.tif
mf.png
mf.tif
ms.png
ms.tif
mtf.png
mtf.tif
pa.png
pa.tif
rc.png
rc.tif
tl.png
tl.tif
tm.png
tm.tif
vp.png
vp.tif