Protocol (E6040) for use with End User Supplied Primers and Adaptors

Protocol

Starting Material: 1-5 μg of Fragmented DNA to 200 bp

End Repair of Fragmented DNA
  1. Mix the following components in a sterile microfuge tube:
    Fragmented DNA:   1–85 μl
    NEBNext End Repair Reaction Buffer (10X):   10 μl
    NEBNext End Repair Enzyme Mix:   5 μl
    Sterile H2O for a final volume of 100 μl:   variable 
    -------------------------------------------------------------------
    Total volume:   100 μl
  2. Incubate in a thermal cycler for 30 minutes at 20°C.
Clean Up Using AMPure XP Beads
  1. Vortex AMPure XP beads to resuspend.
  2. Add 160 μl (1.6X) of resuspended AMPure XP beads to the ligation reaction. Mix thoroughly on a vortex mixer or by pipetting up and down at least 10 times.
  3. Incubate for 5 minutes at room temperature.
  4. Put the tube/PCR plate on an appropriate magnetic stand to separate beads from supernatant. After the solution is clear (about 5 minutes), carefully remove and discard the supernatant. Be careful not to disturb the beads that contain DNA targets.
  5. Add 200 μl of 80% freshly prepared ethanol to the tube/PCR plate while in the magnetic stand. Incubate at room temperature for 30 seconds, and then carefully remove and discard the supernatant.
  6. Repeat Step 5 once.
  7. Air dry beads for 10 minutes while the tube/PCR plate is on the magnetic stand with the lid open.
  8. Elute DNA target by adding 50 μl sterile water to the beads. Mix well on a vortex mixer or by pipetting up and down, and put the tube/PCR plate in the magnetic stand until the solution is clear.
  9. Without disturbing the bead pellet, carefully transfer 42 μl of the supernatant to a fresh, sterile microfuge tube.
Alternatively, adaptor ligated DNA can be purified on one purification column. Purify DNA sample on one QIAquick column and elute in 42 μl of sterile water or elution buffer.

dA-Tailing of End Repaired DNA
  1. Mix the following components in a sterile microfuge tube:
    End Repaired DNA 42 μl
    NEBNext dA-Tailing Reaction Buffer (10X)
    5   μl
    Klenow Fragment (3'→5' exo-)
    3 μl
    Total volume 50 μl
  2. Incubate at 37°C for 30 minutes.
Clean up Using AMPure XP Beads
  1. Vortex AMPure XP beads to resuspend.
  2. Add 90 μl (1.8X) of resuspended AMPure XP beads to the ligation reaction. Mix thoroughly on a vortex mixer or by pipetting up and down at least 10 times.
  3. Incubate for 5 minutes at room temperature.
  4. Put the tube/PCR plate on an appropriate magnetic stand to separate beads from supernatant. After the solution is clear (about 5 minutes), carefully remove and discard the supernatant. Be careful not to disturb the beads that contain DNA targets.
  5. Add 200 μl of 80% ethanol to the tube/PCR plate while in the magnetic stand. Incubate at room temperature for 30 seconds, and then carefully remove and discard the supernatant.
  6. Repeat Step 5 once.
  7. Air dry beads for 10 minutes while the tube/PCR plate is on the magnetic stand with the lid open.
  8. Elute DNA target by adding 30 μl sterile water to the beads. Mix well on a vortex mixer or by pipetting up and down, and put the tube/PCR plate in the magnetic stand until the solution is clear.
  9. Without disturbing the bead pellet, carefully transfer 25 μl of the supernatant to a fresh, sterile microfuge tube.
Alternatively, adaptor ligated DNA can be purified on one purification column. Purify DNA sample on one column and elute in 25 μl of sterile water or elution buffer.

Adaptor Ligation of dA-Tailed DNA
  1. Mix the following components in a sterile microfuge tube:

    dA-Tailed DNA:   25 μl
    Quick Ligation Reaction Buffer (5X):   10 μl
    15 μM DNA Adaptors*:   10 μl
    Quick T4 DNA Ligase:   5 μl
    ----------------------------------------------------------------------
    Total volume:   50 μl

  2. * Adaptors are not provided; please use adaptors appropriate to specific application. If necessary adjust the adaptor concentration to a final adaptor to DNA molar ratio of 10:1.
  3. Incubate in a thermal cycler for 15 minutes at 20°C.
Clean Up Using AMPure XP Beads
  1. Vortex AMPure XP beads to resuspend
  2. Add 90 μl (1.8X) of resuspended AMPure XP beads to the ligation reaction (~53 μl). Mix well on a vortex mixer or by pipetting up and down at least 10 times.
  3. Incubate for 5 minutes at room temperature.
  4. Put the tube/PCR plate on an appropriate magnetic stand to separate beads from supernatant. After the solution is clear (about 5 minutes), carefully remove and discard the supernatant. Be careful not to disturb the beads that contain DNA targets.
  5. Add 200 μl of 80% freshly prepared ethanol to the tube/PCR plate while in the magnetic stand. Incubate at room temperature for 30 seconds, and then carefully remove and discard the supernatant.
  6. Repeat Step 5 once.
  7. Air dry beads for 10 minutes while the tube/PCR plate is on the magnetic stand with the lid open.
  8. Elute DNA targetby adding 105 μl sterile water to the beads for bead-based size selection as detailed in the next section, or at desired volume for size selection using E-Gel size select gels or standard 2% agarose gels. Mix well on a vortex mixer or by pipetting up and down, and put the tube/PCR plate in the magnetic stand until the solution is clear.
  9. Transfer 100 μl of the supernatant (or desired volume) to a new tube/well, and proceed to bead based size selection.
Alternatively, adaptor ligated DNA can be purified on one purification column. Elute in sterile water in a volume desired for subsequent size selection.


Size Select Adaptor Ligated DNA Using AMPure XP Beads

Insert Size
150 bp
200 bp
250 bp
300 bp
400 bp
500 bp
 700 bp
Total library size
(insert + adaptor)
270 bp
 320 bp
370 bp
420 bp
530 bp
660 bp
820 bp
Bead: DNA ratio*
1st bead selection
 0.9X  0.8X  0.7X 0.6X
0.55X
0.5X
0.45X
Bead: DNA ratio*
2nd bead selection
 0.2X 0.2X
 0.2X 0.2X
0.15X
0.15X
0.15X

Table 1: Recommended conditions for dual bead-based size selection

Caution: the following size selection protocol is for libraries with 200 bp inserts only. For libraries with larger fragment inserts, please optimize bead: DNA ratio accordingly.

Note: (X) refers to original sample volume of 100 μl.

  1. Add 80 μl (0.8X) resuspended AMPure XP beads to 100 μl DNA solution. Mix well on a vortex mixer or by pipetting up and down at least 10 times.
  2. Incubate for 5 minutes at room temperature.
  3. Place the tube/PCR plate on an appropriate magnetic stand to separate beads from supernatant. After the solution is clear (about 5 minutes), carefully transfer the supernatant to a new tube/well (Caution: do not discard the supernatant). Discard beads that contain the large fragments.
  4. Add 20 μl (0.2X) resuspended AMPure XP beads to the supernatant, mix well and incubate for 5 minutes at room temperature.
  5. Put the tube/PCR plate on an appropriate magnetic stand to separate beads from supernatant. After the solution is clear (about 5 minutes), carefully remove and discard the supernatant. Be careful not to disturb the beads that contain DNA targets (Caution: do not discard beads).
  6. Add 200 μl of 80% freshly prepared ethanol to the tube/PCR plate while in the magnetic stand. Incubate at room temperature for 30 seconds, and then care- fully remove and discard the supernatant.
  7. Repeat Step 6 once.
  8. Air dry beads for 10 minutes while the tube/PCR plate is on the magnetic stand with lid open.
  9. Elute DNA target from beads into 25 μl water or 0.1X TE buffer. Mix well on a vortex mixer or by pipetting up and down, and put the tube/PCR plate in the magnetic stand until the solution is clear.

Note: Be sure not to transfer any beads. Trace amounts of bead carry-over may affect the optimal performance of the polymerase used in the NEBNext High-Fidelity 2X PCR Master Mix in the subsequent PCR step.

    10.  Transfer 20 μl of the supernatant to a clean PCR tube and proceed to enrichment.

Alternatively, adaptor ligated DNA can be size selected using a number of other methods including E-Gel size select gels or standard 2% agarose gels. Prufiy DNA sample on one column and elute in 22 μl of sterile water or elution buffer.


PCR Enrichment Adaptor Ligated DNA
  1. Mix the following components in a sterile microfuge tube:
    DNA  20 μl
    Primer 1 (25 μM)
    2.5 μl
    Primer 2 (25 μM) 2.5 μl
    NEBNext High-Fidelity 2X PCR Master Mix* 
     25 μl
    Total volume 50 μl
    **NEBNext High-Fidelity 2X PCR Master Mix will be replacing Phusion High-Fidelity PCR Master Mix. Both vials will be supplied for a limited time only.
  2. PCR cycling conditions
    Cycle step Temp Time Cycles
    Initial denaturation 98°C 30 sec 1
    Denaturation
    Annealing
    Extension
    98°C
    65°C
    72°C
    10 sec
    30 sec
    30 sec
    4-8*
    Final extension 72°C
    4 °C
    5 min
    hold
    1
  3. *If library construction was performed with 5 μg of starting material, use 4 cycles of amplification. If starting material was 1 μg, use 6-8 cycles of amplification. However, optimization of PCR cycle number may be required to avoid over-amplification.
Clean Up Using AMPure XP Beads
  1. Vortex AMPure XP beads to resuspend.
  2. Add 50 μl (1X) of resuspended AMPure XP beads to the PCR reactions (~50 μl). Mix well on a vortex mixer or by pipetting up and down at least 10 times.
  3. Incubate for 5 minutes at room temperature.
  4. Put the tube/PCR plate on an appropriate magnetic stand to separate beads from supernatant. After the solution is clear (about 5 minutes), carefully remove and discard the supernatant. Be careful not to disturb the beads that contain DNA targets.
  5. Add 200 μl of 80% ethanol to the tube/PCR plate while in the magnetic stand. Incubate at room temperature for 30 seconds, and then carefully remove and discard the supernatant.
  6. Repeat Step 5 once.
  7. Air dry beads for 10 minutes while the tube/PCR plate is on the magnetic stand with the lid open.
  8. Elute DNA target from beads into 30 μl of 0.1X TE. Mix well on a vortex mixer or by pipetting up and down, and put the tube/PCR plate in the magnetic stand until the solution is clear.
  9. Transfer 25 μl of the supernatant to a clean LoBind tube, and store at –20°C.
    Alternatively, adaptor ligated DNA can be purified on one purification column. Purify DNA on one QIAquick column and elute in 27 µl of 0.1X TE Buffer.
  10. Dilute the library 20 fold with nuclease free water, and assess the library quality on a Bioanalyzer (high sensitivity chip). Check that the electropherogram shows a narrow distribution with a peak size approximately 300–320 bp
Figure 1: Example of DNa library size distribution on a bioanalyzer