Genomic DNA Purification from Yeast (NEB #T3010)

Up to 5 x 107 yeast cells can be processed with this protocol. Cell lysis can be accomplished either by enzymatic means or by mechanical disruption; both methods are outlined below. The following protocols have been validated on S. cerevisiae but have not been tested for other yeasts and fungi; however, they would be expected to work well.

Before You Begin:

  • Store RNase A and Proteinase K at -20°C.
  • Add ethanol (≥ 95%) to the Monarch gDNA Wash Buffer concentrate as indicated on the bottle label.
  • For Enzymatic Lysis:
    • Set a thermal mixer or heating block to 37°C for enzyme incubation.
    • Ensure that a suitable enzyme and corresponding buffer are available to break down the yeast glycan cell wall and form partial spheroplasts. The protocol describes the use of Zymolyase (we recommend D-Zymolyase from Zymo Research, which includes RNase A), but other enzymes may be used as well (e.g. lyticase, chitinase or gluculase).<
  • For Mechanical Lysis— Cold PBS or 10 mM Tris-HCl pH 8.0 is required(not supplied).
    • The use of a bead mill is required.
    • Please defer to manufacturer’s instructions on bead size, amount and settings.
  • Set a thermal mixer (e.g. ThermoMixer or similar device), or a heating block to 56°C for sample lysis.
  • To prepare for elution, set a heating block to 60°C. Preheat the appropriate volume of elution buffer
  • to 60°C (35–100 μl per sample). Confirm the temperature, as temperatures are often lower than indicated on the device.

Enzymatic Lysis

  1. Harvest up to 5 x 107 yeast cells by centrifugation for 1 minute at > 12,000 x g. Discard supernatant.

  2. Add 100 μl of the lytic enzyme’s digestion buffer and resuspend yeast cell pellet by vortexing or pipetting up and down.

  3. Add lytic enzyme (according to manufacturer’s protocol). If the lytic enzyme is not pre-mixed with RNase A,  also add 3 μl RNase A.

  4. Incubate for 30 min at 37°C or until spheroplast formation is complete.

  5. Add 10 μl Proteinase K and vortex briefly.

  6. Add 100 μl Tissue Lysis Buffer and vortex thoroughly.

  7. Incubate at 56°C for a minimum of 30 minutes in a thermal mixer with agitation at full speed (~1400 rpm).

  8. Proceed to Genomic DNA Binding and Elution.

Mechanical Lysis

  1. Harvest up to 5 x 107 yeast cells by centrifugation for 1 minute at > 12,000 x g. Remove supernatant.

  2. Resuspend pellet in 150 μl cold PBS or 10 mM Tris-Cl pH 8.0.

  3. Add 150 μl Tissue Lysis Buffer and mix briefly by vortexing or pipetting up and down.

  4. Transfer to a bead-mill tube containing the appropriate amount of beads. Disrupt at the appropriate settings (e.g. 30 seconds at position 6.0 in an MP Biomedical Fast-Prep®-24).

  5. Transfer 200 μl of the homogenized cell lysate to a new tube, taking care not to carry over foam that may have formed.

  6. Add 10 μl Proteinase K, vortex briefly, and incubate at 56°C for 10 minutes in a thermal mixer with agitation at full speed (~1400 rpm).
     
  7. Add 3 μl of RNase A, vortex briefly, and incubate for a minimum of 5 minutes at 56°C with agitation at full speed.|

  8. Proceed to Genomic DNA Binding and Elution.

 

GENOMIC DNA BINDING AND ELUTION

  1. Add 400 μl gDNA Binding Buffer to the sample and mix thoroughly by pulse-vortexing for 5-10 seconds. Thorough mixing is essential for optimal results.

  2. Transfer the lysate/binding buffer mix (~600 μl) to a gDNA Purification Column pre-inserted into a collection tube, without touching the upper column area. Proceed immediately to step 3. Avoid touching the upper column area with lysate/binding mix and avoid transferring foam that may have formed during lysis. Any material that touches the upper area of the column, including any foam, may lead to salt contamination in the eluate.

  3. Close the cap and centrifuge: first for 3 minutes at 1,000 x g to bind gDNA (no need to empty the collection tubes or remove from centrifuge) and then for 1 minute at maximum speed (> 12,000 x g) to clear the membrane. Discard the flow-through and the collection tube. For optimal results, ensure that the spin column is placed in the centrifuge in the same orientation at each spin step (for example, always with the hinge pointing to the outside of the centrifuge); ensuring the liquid follows the same path through the membrane for binding and elution can slightly improve yield and consistency.

  4. Transfer column to a new collection tube and add 500 μl gDNA Wash Buffer. Close the cap and invert a few times, so that the wash buffer reaches the cap. Centrifuge immediately for 1 minute at maximum speed (12,000 x g), and discard the flow through. The collection tube can be tapped on a paper towel to remove any residual buffer before reusing it in the next step. Inverting the spin column containing wash buffer prevents salt contamination in the eluate.

  5. Reinsert the column into the collection tube. Add 500 μl gDNA Wash Buffer and close the cap. Centrifuge immediately for 1 minute at maximum speed (>12,000 x g), then discard the collection tube and flow through.

  6. Place the gDNA Purification Column in a DNase-free 1.5 ml microfuge tube (not included). Add 35-100 μl preheated (60°C) gDNA Elution Buffer, close the cap and incubate at room temperature for 1 minute. Elution in 100 μl is recommended, but smaller volumes can be used and will result in more concentrated DNA but a reduced yield (20–25% reduction when using 35 μl). Eluting with preheated elution buffer will increase yields by ~20–40% and eliminates the need for a second elution. For applications in which a high DNA concentration is required, using a small elution volume and then eluting again with the eluate may increase yield (~10%). The elution buffer (10 mM Tris-Cl, pH 9.0, 0.1 mM EDTA) offers strong protection against enzymatic degradation and is optimal for long term storage of DNA. However, other low-salt buffers or nuclease-free water can be used if preferred. For more details on optimizing elution, please refer to “Considerations for Elution & Storage” in the product manual.

  7. Centrifuge for 1 minute at maximum speed (> 12,000 x g) to elute the gDNA. 

 

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