Article Title: Uridylation by TUT4/7 Restricts Retrotransposition of Human LINE-1s
Figure Lengend Snippet: Graphical Visualization of the 3′ RACE-Seq Approach, Related to Figure 2 (A) Graphical representation of 3′ RACE-seq library preparation and the oligonucleotides used. First, the 3′ adaptor RA3_15N was joined to the 3′ end of RNA by enzymatic ligation. The adaptor has: (i) 5′ rApp modification for efficient and specific ligation by the truncated T4 RNA ligase 2, (ii) delimiter sequence to be used in bioinformatics analyses to exclude RT and PCR artifacts (CTGAC, highlighted in violet), (iii) unique 15N barcode for individual transcript barcoding (highlighted in green), (iv) anchor sequence to pair with the reverse transcription primer (underlined) and (v) dideoxyC on the 3′ end to prevent concatamer formation. The RNA ligated to the adaptor sequence was purified from excess adaptor and reverse transcription was performed with the RT primer, which is compatible with Illumina sequencing and has: (i) sequences to base-pair with the adaptor (underlined), (ii) 6-nucleotide barcode for sample barcoding (highlighted in red), (iii) sequences that base pair with the universal outer primer for nested PCR (blue). Libraries were generated by nested PCR with 2 outer forward primers (F1 and F2) and a single universal reverse primer (uni rev). PCR amplicons of first and second PCRs were purified from excess primers on AmPure beads (Agencourt) before beginning the next step. (B) Flowchart of the bioinformatics approach to 3′ RACE-seq data analysis. The procedure starts at the top. Datasets are shown in rectangles. Software used is depicted in hexagons.
Article Snippet: The reactions were carried out in 20 μL with 1x T4 RNA ligase 2 truncated buffer (NEB) supplemented with PEG-8000 at 10% final concentration, 0.25 U/μl RiboLock inhibitor (Thermo Fisher Scientific), 3 pmol of the 5′ FAM-labeled 44-mer oligonucleotide RNA44 (Future Synthesis) and 300 U T4 RNA ligase 2 truncated (NEB) for 18h at 18°C.
Techniques: Ligation, Modification, Sequencing, Polymerase Chain Reaction, Purification, Nested PCR, Generated, Software