title: GSM9245030: 16-20 h embryo, ft-GFP[C], Replicate 3, NovaSeq X Plus (ChIP); Drosophila melanogaster; ChIP-Seq
library_construction_protocol: Embryos were collected for 4 hrs, aged for 16 hrs at 25C, and dechorionated in 50% bleach.  Eye-brain complexes were dissected from 3rd instar larvae in ice-cold PBS.  Tissues were crosslinked in 2 mM EGS for 45 min, followed by paraformaldehyde for 15 min, quenched, washed, flash frozen in liquid nitrogen and stored at -80C until use.  50 ml settled embryos or 100 eye-brain complexes were used per sample.  Crosslinked tissues were homogenized by douncing, followed by nuclear lysis and sonication of the genomic DNA using a Bioruptor or Qsonica Q700 sonicator.  Fragmented chromatin was incubated with anti-GFP or anti-FLAG antibodies and precipitated using MagnaChIP A+G beads or Dynabeads G. ChIP-seq libraries were prepared from 10 ng DNA.  DNA was blunt ended, had an A base added to the 3' ends, and then had Illumina sequencing adapters ligated to the ends.  Size selection was performed with AMPure beads to limit the fragment size to 150-700 bp.  Ligated fragments were then amplified for 15 cycles using primers incorporating unique dual index tags.
identifiers.namespace: GEO
identifiers.id: GSM9245030_r1