Fig. 1

Generation of small RNAs by telomeric transgenes. a Schematic structure of telomeric elements is shown above. Insertion sites of transgenes are indicated as triangles situated above and below the schemes, which correspond to their genomic orientation. The profiles of small RNAs in ovaries of yw strain are shown along the canonical sequences of HeT-A, TAHRE, TART-A, TART-B, and TART-C telomeric retrotransposons. Normalized numbers of small RNAs (RPM, reads per million, 0–3 mismatches) in a 30-bp window were calculated. Length distribution of the telomeric element small RNAs is shown below. Percentages of reads having 1U are indicated for each strand (only 24–29-nt reads were considered). b Scheme of transgenic insertion sites in euchromatin and TAS of chromosome 2R. c Normalized numbers of small RNAs mapped to transgenic constructs (blue–sense; brown–antisense; no mismatches allowed). Mapping of piRNAs (24–29 nt) and siRNAs (21 nt) onto the transgenes is shown separately. Scheme of the P{EPgy2} transgene is shown above. Short names of telomeric insertions are indicated. d Length distribution of transgenic small RNAs. Percentage of reads having 1U are indicated for each strand (only 24–29-nt reads were considered). e Relative frequencies (Z-score) of 5′ overlap for sense and antisense 24–29-nt piRNAs (ping-pong signature). f Northern blot hybridization of the RNA isolated from the ovaries of EY08176, EY03383, EY00453, EY00802, EY09966, and EY03241 strains was done with the white riboprobe to detect antisense piRNAs. Lower panel represents hybridization to mir-13b1 microRNA. P³²-labeled RNA oligonucleotides were used as size markers