Figure 1.

Piwi associates with chromatin and nuclear transcripts. (A) Polytene chromosomes from Drosophila nurse cells expressing GFP-Piwi on the otu[7]/otu[11] background. Piwi pattern on chromosomes correlates with Pol II staining. (B) Mass spectrometry analysis of Piwi interaction partners. Piwi complexes were precipitated in the presence and absence of RNase A. The outer circle represents classification of Piwi-associated proteins based on GO term analysis. The inner pies represent the fraction of each group whose association with Piwi depends on RNA (percentage indicated). Note that chromatin, splice, and mRNA export factors are virtually absent after RNase A treatment.