Figure 7

Expression of dh repeats at the sub-telomere. (a) Expression of sub-telomeric dh repeats in trt1^- mutants. Strand-specific RT-PCR using primers spanning the region of dh repeats in the putative helicase (P _dh in Figure 6) was used to detect the expression of both forward (For) and reverse (Rev) transcripts. We define the forward transcript to be homologous to the DNA strand running towards the chromosome end in the 5' to 3' direction (this is also the strand with the longest ORF). Strand-specific control reactions were also performed using primers specific for centromeric (Cen) dh repeats [33], as well as act1⁺ sense and act1⁺ antisense transcripts (a control lacking reverse transcriptase is labeled -RT). Strains WT 5 and days 1, 7, 9 and 15 of the growth curve are shown. (b) Expression of sub-telomeric dh repeats in RNAi mutants. RNA was isolated from trt1⁺ RNAi mutant strains ago1^-, dcr1^- and rdp1^- [33], and subjected to strand-specific RT-PCR using the same primers described in (a). A different wild-type strain from that in (a) was used.