Briefly, small pieces of frozen testis tissue were cross-linked with 2% (w/v) formaldehyde at room temperature for 30 min using end-over-end tumbler. We next crushed fixed tissues in the presence of ChIP lysis buffer (1% SDS, 10mM EDTA, 50mM Tris-HCl pH 8.1) by 40 strokes with a “B” pestle of Dounce homogenizer (Kimble-Chase, Vineland, USA). Thereafter, lysate was sonicated using Covaris ultrasonicator (Covaris, E220) to shear the chromatin to 150–200 bp. Lysate was then diluted 1:10 with ChIP dilution buffer (0.01% SDS, 1.1% Triton X-1001.2 mM EDTA, 16.7 mM Tris-HCl pH 8.1, 167 mM NaCl).  We performed immunoprecipitation using 6 µg rabbit polyclonal anti-H3K27Ac antibody (Abcam, ab4729). Following the immunoprecipitation, we extracted DNA with phenol:chloroform:isoamyl alcohol. Libraries construction for anti-H3K27Ac, and input DNA were performed after DNA extraction as previously described (Zhang, Z., Theurkauf, W.E., Weng, Z., and Zamore, P.D. (2012). Strand-specific libraries for high throughput RNA sequencing (RNA-Seq) prepared without poly(A) selection. Silence 3, 9.). none provided by the submitter