upstream T7 RNA polymerase promoter (underlined in the
sequence) to perform T7 transcription.
18S forward primer:
50 - TAATACGACTCACTATAGGTATCTGGTTGATCCTG-
CCAGTAG-3^0.
18S reverse primer: 5^0 -TAATGATCCTTCCGCAGGTTC-3^0.
25S forward primer:
50 - TAATACGACTCACTATAGGGTTTGACCTCAAATCA-
GGTAGG-3^0.
25S reverse primer: 5^0 -ACAAATCAGACAACAAAGGC-3^0
- 25 ng/μL plasmid DNA template pHW18 (seeNote 1).
- 2.5 U/μL Pfu DNA polymerase.
- 10Pfu DNA polymerase buffer.
- dNTP mix: 1.25 mM each.
- RNase-free water.
- Individual RNase-free 0.2 mL PCR tubes.
- PCR thermal cycler (e.g., Agilent SureCycler 8000).
- RNAse-free 1.5 mL microcentrifuge tubes.
- Phenol–chloroform mix (1:1, v/v).
- 3 M Na-Acetate (NaOAc) in water, pH 5.2.
- 96% ethanol.
- 75% ethanol.
- Tabletop centrifuge.
2.2 In Vitro Yeast
rDNA Transcription
and RNA Purification
2.2.1 In Vitro Yeast rDNA
Transcription
- 5Transcription buffer: 400 mM HEPES–KOH, pH 7.5,
120 mM MgCl 2 , 10 mM spermidine, 200 mM DTT. - 40 U/μL RiboLock RNase Inhibitor.
- rNTP mix: 12.5 mM each.
- 400 nM 18S and 450 nM 25S PCR templates.
- 20 U/μL T7 RNA polymerase.
- RNAse-free 1.5 mL microcentrifuge tubes.
- 37C incubator.
- 1 U/μL RQ1 RNase-free DNase.
2.2.2 Purification of In
Vitro Transcripts
- RNase-free water.
- Phenol–chloroform mix (1:1, v/v).
- Chloroform.
- 5 M ammonium acetate (NH 4 OAc).
- 10 mg/mL glycogen coprecipitant.
- Refrigerated tabletop centrifuge.
- 96% ethanol.
Quantification of 2^0 - O-Me by RiboMethSeq 31