Tag Archives: MBD-Seq

EtOH Precipitation – LSU C.virginica Oil Spill MBD Continued (from 20141126)

Precipitation was continued according to the MethylMiner Methylated DNA Enrichment Kit (Invitrogen). Since I will need sample volumes of 24uL for the subsequent bisulfite conversion, I resuspended the samples in 29uL of water (will use 2.5uL x 2 reps for quantification).

Samples to be quantified:

NC = non-captured (i.e. non-methylated)

E = eluted (i.e. methylated)

  • HB2 NC
  • HB5 NC
  • HB16 NC
  • HB30 NC
  • NB3 NC
  • NB6 NC
  • NB11 NC
  • NB21 NC
  • HB2 E
  • HB5 E
  • HB16 E
  • HB30 E
  • NB3 E
  • NB6 E
  • NB11 E
  • NB21 E
  • Control NC
  • Control E

Samples were quantified using the Quant-IT BS Kit (Invitrogen) with a plate reader (BioTek). All samples were run in duplicate. Used 2.5uL of each sample for quantification.

Samples were stored in @ -20C (FTR 209) in the bisulfite seq box created by Claire for this project.





Methylated DNA Enrichment (MBD) – LSU C.virginica Oil Spill gDNA

Enrichment was performed using the MethylMiner Methylated DNA Enrichment Kit (Invitrogen) according to the manufacturer’s protocol with the following changes:

– Used 25uL of Dynabeads M-280 (10uL/ug of input DNA) and 15uL of MBD-Biotin Protein (7uL/ug of input DNA).

– Followed the corresponding instructions for the volumes listed above and for quantities of input DNA > 1ug – 10ug

– A single elution with 2000mM NaCl was performed

– EtOH precipitation: Samples were incubated over the long weekend at -80C.


Gel – Sheared LSU C.virginica Oil Spill gDNA (from yesterday)

Ran ~250ng of sheared C.virginica gDNA from yesterday’s shearing.


Ladder used: O’GeneRuler 100bp Ladder (ThermoFisher)

The shearing is, surprisingly, very inconsistent across the samples. The target average fragment size was ~350bp. However, most of these samples are <250bp. The MethylMiner Kit (Invitrogen) suggests that an average fragment length of 100 – 200bp is ideal for short-read high-throughput sequencing, but we’re going to perform a bisulfite conversion on these which will result in some additional fragmentation, further reducing the average fragment size. Will proceed with methylated DNA enrichment.


DNA Shearing – LSU C.virginica Oil Spill gDNA

Used the remainder of the “sheared” samples (see today’s earlier entry; ~2750ng). Brought the volumes up to 80uL and transferred to 0.5mL snap cap tubes. The volume of 80uL was selected because it’s above the minimum volume required for shearing in 0.5mL tubes (10uL according to the Biorupter 300 manual) and the MethylMiner Kit (Invitrogen) requires the input DNA volume to be <= 80uL.

DNA was sheared with the following parameters:

Low power

30 cycles of:

30s on

30s off

Target average fragment size is ~350bp.

See tomorrow (20141126) for the gel.


Gel – Sheared gDNA

Ran ~250ng (out of 3000ng, according to Claire) of LSU C.virginica oil spill gDNA on a gel that was previously sheared by Claire to verify that shearing was successful.

Ran unsheared side-by-side with sheared gDNA for comparison.

Note: HB16 and NB3 did not have any unsheared gDNA left in their tubes, so nothing was run on a gel.


Ladder used: O’GeneRuler 100bp Ladder (ThermoFisher)

Well, it’s rather obvious that the initial shearing did NOT work. Will re-shear the samples.

UPDATE: Looking at the Biorupter (Diagenode) manual, it turns out that shearing samples in a 1.5mL tube (in which these were sheared) requires a minimum volume of 100uL. All the samples were far below this minimum volume. Additionally, the recommendations in the manual to reach the target size range are significantly longer (30 – 40 cycles) than what was applied (4 cycles). The combination of these two factors are likely the reason that shearing didn’t take place.