Fig. 4: To repress Ste, aub and ago3 are required no later than the spermatogonial four-cell stage. | Nature Cell Biology

Fig. 4: To repress Ste, aub and ago3 are required no later than the spermatogonial four-cell stage.

From: A maternally programmed intergenerational mechanism enables male offspring to make piRNAs from Y-linked precursor RNAs in Drosophila

Fig. 4: To repress Ste, aub and ago3 are required no later than the spermatogonial four-cell stage.The alternative text for this image may have been generated using AI.

a–i, Representative images of Ste smRNA-FISH (red) in the testes in control y1w1118 testis (a) and in piRNA pathway mutant testes of the indicated genotypes: aub nos-driven RNAi (b); aub bam-drive RNAi (c); ago3 nos-driven RNAi (d); ago3 bam-driven RNAi (e); aub mutant (f); aub mutant, bam-driven rescue (g); ago3 mutant (h), ago3 bam-driven rescue (i). GSCs and early SGs are indicated by a yellow dotted line; cyan lines indicate spermatocytes. The asterisks indicate the hub. Scale bars, 20 µm. Experiments were repeated three times with similar results. These results show that Aub and Ago3 programmed with antisense Su(Ste) piRNAs are required for efficient repression of Ste. Note that, in fly testes and ovaries, transposon-derived piRNAs partition between Aub and Ago3: most antisense, phased, 1U-enriched piRNAs are bound to Aub, while most sense, ping-pong produced, 10A-biased piRNAs are loaded in Ago3 (refs. 4,54). Yet antisense, phased, 1U-enriched Su(Ste) piRNA are loaded into both Aug and Ago3 (ref. 54). Our analyses also show that piRNAs produced from the cleavage products of slicing of Ste transcripts by Su(Ste) piRNAs (that is, responder Ste piRNAs1) are most frequently loaded in Ago3 (>51 ± 8% in Ago3 versus >7 ± 2% in Aub).

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