8 gDNA samples from SB were pooled and 8 gDNA samples from WB were pooled, using equal amounts of gDNA from each sample (1250ng) for a total of 10ug (see SB/WB Mac’s MeDIP spreadsheet for specific samples/volumes used in pooling). Since samples were stored in pH-adjusted NaOH (see 20100605), they needed to be precipitated in order to have the gDNA suspended in TE for the downstream steps of methylated DNA immunoprecipitation (MeDIP). 10% 3M sodium acetate (pH = 5.2) was added to each tube, then 2.5 vols of 100% EtOH and mixed. Samples were incubated @ -20C for 30mins. DNA was pelleted by spinning 16,000g for 30mins @ 4C. Supe was discarded. Pellets were washed with 1mL 70% EtOH and then pelleted @ 16,000g for 10mins @ 4C. Supe was discarded and gDNA was resuspended in 120uL of TE (pH = 8.0) and spec’d.

Results:

The R37 (SB) sample pool yielded 7.056ug after precipitation and the R51 (WB) sample pool yielded 8.834ug after precipitation (started with 10ug). This is good, as 6ug is needed for MeDIP and I wanted to have some (~250ng) available for running as an un-sonicated control on the post-sonication gel. Will transfer 250ng from each pool to separate tubes and then proceed with sonication.