Figure 4. Antisense transcription at the target locus correlates with the ability of ura4-h5 hairpin to induce silencing.

A, Schematic diagram of two different ura4⁺ replacements of leu1⁺, leu1Δ::ura4⁺ and leu1Δ::ura4⁺/kanMX. The two loci are identical, except that the latter contains an ADH1 terminator and kanMX antibiotic resistance marker downstream of the inserted ura4⁺ sequences. a and b denote pairs of primers used for RT-PCR assays in B. B, RT-PCR assays showing antisense transcription at the leu2Δ::ura4⁺/kanMX but not the leu2Δ::ura4⁺ locus. C, Growth silencing assays showing that the ura4-h5 hairpin induced silencing at the leu2Δ:: ura4⁺/kanMX but not the leu2Δ:: ura4⁺ locus.