Drosophila Ovary and Larval Tissue Staining

Adult Drosophila ovaries were dissected and stained as described in ref. ^{79 (link)}. Wandering third instar larval tissues were processed similarly to adult ovaries with one additional permeabilization step with 0.1% TritonX-100 in 1X PBS for 1 h at room temperature immediately following fixation. Primary antibodies were diluted in 5% BSA, 0.3% TritonX-100 in PBS and are listed in Supplementary Table 2. Alexa Fluor-conjugated secondary antibodies were used at a 1:500 dilution. All images were collected on a Zeiss LSM 710 Confocal Microscope, cropped and rotated using ImageJ software, size matched with Adobe Photoshop and assembled with Adobe Illustrator. The number of HP1a foci was quantified manually using ImageJ. Unless otherwise noted, all images are a single slice of a confocal stack.