Details

Autor(en) / Beteiligte

• Wang, Sidney H
• Elgin, Sarah C. R

Titel

Drosophila Piwi functions downstream of piRNA production mediating a chromatin-based transposon silencing mechanism in female germ line

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2011-12, Vol.108 (52), p.21164-21169

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2011

Quelle

EZB-FREE-00999 freely available EZB journals

Beschreibungen/Notizen

• Transposon control is a critical process during reproduction. The PIWI family proteins can play a key role, using a piRNA-mediated slicing mechanism to suppress transposon activity posttranscriptionally. In Drosophila melanogaster, Piwi is predominantly localized in the nucleus and has been implicated in heterochromatin formation. Here, we use female germ-line–specific depletion to study Piwi function. This depletion of Piwi leads to infertility and to axis specification defects in the developing egg chambers; correspondingly, widespread loss of transposon silencing is observed. Germ-line Piwi does not appear to be required for piRNA production. Instead, Piwi requires Aubergine (and presumably secondary piRNA) for proper localization. A subset of transposons that show significant overexpression in germ-line Piwi-depleted ovaries exhibit a corresponding loss of HP1a and H3K9me2. Germ-line HP1a depletion also leads to a loss of transposon silencing, demonstrating the functional requirement for HP1a enrichment at these loci. Considering our results and those of others, we infer that germ-line Piwi functions downstream of piRNA production to promote silencing of some transposons via recruitment of HP1a. Thus, in addition to its better-known function in posttranscriptional silencing, piRNA also appears to function in a targeting mechanism for heterochromatin formation mediated by Piwi.