Synchronized worms were cultured in liquid and harvested at early L4 stage by sucrose flotation. The worms were lysed via Teflon homogenizer in cold PBS with protease inhibitors (Roche). Cross-linking of DNA and protein was performed by treating the worms with 1.85% formaldehyde for 15 min. Glycine was added to a final concentration of 125mM for 5 min at room temperature to quench the formaldehyde. The pellets were resuspended twice in cold PBS with protease inhibitor. Samples were sonicated in Bioruptor (Diagenode) for 15 min at 4°C on high intensity (30s on and 30s off). Samples were transferred to microfuge tubes and spun at 15,000*g for 15 min at 4°C. The supernatant was precleaned with pre-blocked ChIP-grade Pierce™ magnetic protein A/G (Thermo Scientific) and then incubated with Monoclonal ANTI-FLAG® M2 antibody (Sigma, F1804) or Mouse mAb IgG1 Isotype Control (Cell Signaling Technology, G3A1) rotating overnight at 4°C. Then, the antibody-chromatin complex was precipitated with magnetic beads or protein A sepharose beads (Invitrogen) dependent on the host of generated antibodies. After washing, the crosslinks were reversed by incubation at 65 °C overnight and further treated with RNaseA 37 °C for 1 hour and then proteinase K 55 °C for 2 hours, respectively. Finally, immunoprecipitated and input DNA were purified with ChIP DNA Clean & Concentrator (Zymo Research, D5205) and used as templates for qPCR or next generation sequencing.