Product Description
The KAPA Stranded mRNA-Seq Kit contains all of the buffers and enzymes required for poly(A) mRNA capture and construction of stranded mRNA-seq libraries from 100 ng – 4 μg of intact, total RNA via the following steps:
- mRNA capture using magnetic oligo-dT beads;
- fragmentation using heat and magnesium;
- 1st strand cDNA synthesis using random priming;
- 2nd strand synthesis and marking, which converts the cDNA:RNA hybrid to double-stranded cDNA (dscDNA),and incorporates dUTP into the 2nd cDNA strand;
- A-tailing, to add dAMP to the 3'-ends of the dscDNA library fragments;
- adapter ligation, where dsDNA adapters with 3'-dTMP overhangs are ligated to A-tailed library insert fragments; and
library amplification, to amplify library fragments carrying appropriate adapter sequences at both ends using highfidelity, low-bias PCR. The strand marked with dUTP is not amplified, allowing strand-specific sequencing.
This kit provides all of the enzymes and buffers required for mRNA enrichment, cDNA synthesis, and library construction and amplification, but does not include RNA, adapters, or beads. KAPA Pure Beads and KAPA Adapters are sold separately. Reaction buffers are supplied in convenient formats comprising all of the required reaction components. This minimizes the risk of RNase contamination, ensures consistent and homogenous reaction composition, and improves uniformity among replicate samples. Similarly, a single enzyme mixture is provided for each step of the library construction process, reducing the number of pipetting steps.
In order to maximize sequence coverage uniformity and to maintain relative transcript abundance, it is critical that library amplification bias be kept to a minimum. KAPA HiFi DNA Polymerase is designed for low-bias, highfidelity PCR, and is the polymerase of choice for NGS library amplification1,2,3,4. KAPA Stranded mRNA-Seq Kits include KAPA HiFi HotStart ReadyMix (2X) and Library Amplification Primer Mix (10X) for library amplification.
- Oyola, S.O., et al., BMC Genomics 13, 1 (2012).
- Quail, M.A., et al., Nature Methods 9, 10 (2012).
- Quail, M.A., et al., BMC Genomics 13, 341 (2012).
- Ross, M.G., et al., Genome Biology 14, R51 (2013).
Product Applications
The KAPA Stranded mRNA-Seq Kit is designed for both manual and automated NGS library construction from 100 ng – 4 μg of intact, total RNA. The protocol is applicable to a wide range of RNA-seq applications, including:
• gene expression
• single nucleotide variation (SNV) discovery
• splice junction and gene fusion identification
• characterization of polyadenylated RNAs.
Process Workflow
Library Construction Protocol
Reagent Preparation
This protocol takes 8 – 10 hrs to complete. Ideally, master mixes for the various steps in the process should be prepared as required.
For maximum stability and shelf-life, enzymes and reaction buffers are supplied separately in the KAPA Stranded mRNA-Seq Kit. For a streamlined“with-bead” protocol, a reagent master mix with a minimum of 10% excess is prepared for each of these enzymatic steps, as outlined in Tables 2 – 6.
Volumes of additional reagents required for the KAPA Stranded mRNA-Seq Kit protocol are listed in Table 7.
In some cases, master mixes may be constituted with varying proportions of the total final water requirement. In the examples given in the tables below, all the required water is included in each master mix, allowing the entire reaction mix to be added in a single pipetting step.
At the safe stopping point at A-tailing, a portion of the water and reaction buffer are added to the beads for storage at 2°C to 8°C for ≤24 hrs. To resume library construction, prepare the master mix with the remaining volume of water and reaction buffer, and the required volume of enzyme. Recommendations on how to formulate the master mix after the safe stopping point are provided in Table 4B.
Always ensure that KAPA Pure Beads and PEG/NaCl Solution are fully equilibrated to room temperature before use.
Table 2. 1st strand synthesis
Table 3. 2nd strand synthesis and marking
Table 4A. A-tailing (uninterrupted protocol)
Table 4B. A-tailing (safe stopping point)
Table 5. Adapter ligation
Table 6. Library amplification
Table 7. Volumes of additional reagents required
mRNA Capture
This protocol requires 100 ng – 4 μg of intact, total RNA in 50 μL of RNase-free water. Degraded or fragmented total RNA will result in significant 3'-bias.
This protocol has been optimized to isolate mature mRNA from total RNA through two subsequent capture steps using the mRNA Capture Beads. Other RNA molecules with homopolymeric adenosine regions may also be isolated.
RNA samples should only be kept on ice where specified in this protocol, since low temperatures may promote non-specific capture, resulting in increased rRNA in the captured mRNA.
Before starting, equilibrate mRNA Capture Beads, mRNA Bead Binding Buffer, mRNA Bead Wash Buffer and Fragment, Prime and Elute Buffer to room temperature.
Before use, beads must be washed with mRNA Bead Binding Buffer (steps 2.1 – 2.5). - mRNA Elution, Fragmentation and Priming
- 1st Strand Synthesis
- 2nd Strand Synthesis and Marking
- 2nd Strand Synthesis and Marking Cleanup
- A-tailing
A-tailing is performed either directly after the 2nd Strand Synthesis and Marking Cleanup, or after the Safe Stopping Point, where beads were resuspended in A-Tailing Buffer (1X) and stored at 2 °C to 8 °C for ≤ 24 hrs. Depending on your chosen workflow, proceed with either A-tailing Immediately (step 7A) or A-tailing after Safe Stopping Point (step 7B).
7A. A-tailing Immediately
7B. A-tailing after Safe Stopping Point
- Adapter Ligation
- 1st Post-ligation Cleanup
- 2nd Post-ligation Cleanup