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  • Protocol (E6000) for use with End User Supplied Primers and Adaptors

    Protocol

    Starting Material: 1–5 μg of Fragmented DNA to 200 b
     
    End Repair of Fragmented DNA
    1. Mix the following components in a sterile microfuge tube:
      Fragmented DNA 1-75 μl
      Phosphorylation Reaction Buffer (10X)    10 μl
      T4 DNA Polymerase 5 μl
      Deoxynucleotide Solution Mix 4 μl
      T4 Polynucleotide Kinase 5 μl
      DNA Polymerase I, Large (Klenow) 1 μl
      Sterile H2O 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 the 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 40 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 32 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 32 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, Blunt DNA 32 μl
      NEBuffer 2 (10X) 5 μl
      Deoxyadenosine 5'-Triphosphate       10 μl
      Klenow Fragment (3' → 5' exo-) 3 μl
      Total volume 50 μl
    2. Incubate in a thermal cycler for 30 minutes at 37°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. 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 the 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 15 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 10 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 MinElute® (Qiagen) column and elute in 10 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 10 μl
      Quick Ligation Reaction Buffer (2X) 25 μl
      Adaptors (15 M)* 10 μl
      Quick T4 DNA Ligase 5 μl
      Total volume 50 μl
      *Adaptors are not provided; please use adaptors appropriate to the specific application. If necessary adjust the adaptor concentration to a final adaptor to DNA molar ratio of 10:1.
    2. 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 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 the 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 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 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
    tttttSize 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.
    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 freshly prepared 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.
    7. Repeat Step 6 once.
    8. Air dry beads for 10 minutes while the tube/PCR plate Is on the magnetic stand with the lid open.
    9. Elute DNA target from the beads into 25 μl sterile 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. Purify 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.

    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
      *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 the DNA targets.
    5. Add 200 μl of freshly prepared 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 the beads for 10 minutes while the tube/PCR plate is on the magnetic stand with the lid open.
    8. Elute DNA target from the 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 25μl 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.