Worms are frozen, ground, crosslinked for 20 minutes in EGS, and for an additional 10 minutes in EGS plus formaldehyde. Later, washed pellets are resuspended in FA buffer and subjected to sonication in Bioruptor (20-30 pulses of 30 seconds with 1 minute rests in between). Extracts are then spun down and soluble fraction is stored for quality tests and future ChIP. Worm_chromatin_immunoprecipitation_vIL2. Appropriate amount of extract is incubated overnight with a proper amount of antibody (exceptional antibodies due to better results are incubated 2hrs). Afterwards, 40ul of equilibrated magnetic beads (either protein A or G, depending on antibody) are added and incubated for 2 hrs. Later, washes with FA, 500mM-salt FA, 1M salt FA, TEL, and TE buffer are performed and DNA is eluted in elution buffer (1% SDS in TE with 250 mM NaCl) ? two times with 57 ?l volume each, at 65°C. Samples are treated with RNAse, proteinase K and then crosslinks are reversed overnight at 65°C. DNA is purified on Qiagen PCR purification columns, tested by q-PCR for ChIP quality, and stored at -20°C for future applications. DNA was incubated with an enzyme mix (Klenow, T4 DNA polymerase and T4 PNK) to ensure blunt ends and then with Exo(-) Klenow fragment in the presence of dATP to add adenosine at the 3? ends. The DNA fragments were ligated with appropriate adaptor (Illumina) and then amplified by PCR. The amplicon was loaded into an agarose gel, and size-selected DNA was recovered from the gel. Prepared sample are sequenced using Illumina GAII or HiSeq2000 at the High Throughput Sequencing Facility of University of North Carolina at Chapel Hill or Cambridge.