Fig. 2.

Transcription-based sample preparation methods. a T7 in vitro transcription scheme; the double-stranded (dsDNA) T7 promoter sequence and 5′-methoxy modification of the DNA template strand are highlighted. b Position-selective labeling of RNA in the solid and solution phase (left). Fundamental steps in one cycle that correspond the production of a single RNA transcript from one DNA template (right). c Polymerase chain transcription components (DNA template, asymmetric DNA primers, and SFM4-3 Pol) and reaction cycles. The RNA is exponentially amplified through thermal cycling transcription reactions; the DNA–RNA chimeras are subsequently digested to obtain the final RNA products. Abbreviations: biot biotin, nt nucleotide, NTP nucleotide triphosphate, RNAP RNA polymerase, SA streptavidin, ssDNA single-stranded DNA