HiC-SN-rep2 (CRX2069142)
100 oocytes (per sample) were fixed in  1%  formaldehyde for 10 min at RT and 2.5 M glycine was added to quench for 5 min at RT. Oocytes were transferred to 100 ul of PBS with 0.05% PVP and captured by  ConA Beads Pro for 10 min at RT. Oocytes were lysed in  lysis buffer for 15 min on ice. Supernatants were discarded with 2.25 ul remaining, and of 5% SDS was added before incubating for 10 min at 62oC. 7.25 ul of nuclease-free water and 1.25 ul of 10% Triton X-100 were added to quench for 15 min at 37oC, and 1.25 ul of 10x NEBuffer 2 (NEB) and 5 U of MboI (NEB) were added to digest chromatin overnight at 37oC. The samples were incubated for 20 min at 62oC to inactivate MboI and then cooled to RT. 2.5 ul of fill-in master mix , 0.3 ul of 10 mM dCTP, 0.3 ul of 10 mM dGTP, 10 mM dTTP and 5 U/ul of DNA polymerase I, Large(Klenow) Fragment (NEB)] was added, and samples were incubated for 90 min at 37oC. Ligation master mix was further added, and samples were incubated for 4 h at RT. After removing supernatants, beads were resuspended with nuclease-free water, Lambda Exonuclease Buffer, Lambda Exonuclease) and Exonuclease I and incubated for 1 h at 37oC. To release DNAs, nuclease-free water, 10% SDS and 20 mg/ml Proteinase K were added, and samples were incubated for 30 min at 55oC. To reverse crosslinks, 5 M NaCl was added, and samples were incubated overnight at 68oC. The next day DNAs were extracted with phenol-chloroform in Phasemaker Tube, precipitated with ethanol and resuspended in 5.5 ul of nuclease-free water. Library preparation was performed using the TruePrep DNA Library Prep Kit V2 for Illumina (Vazyme) following  protocol.