3C-seq for Mef2c
3C-seq was performed as described in (Stadhouders, Kolovos, Brouwer et al., 2013). In brief, 1 × 10^7 cells or dissected SHF regions or tails of 20 E8-9 embryos were crosslinked with 2% formaldehyde at room temperature for 10 min, followed by glycine quenching, cell lysis, HindIII (for 3C-seq of the Mef2c locus) or NlaIII digestion (3C-PCR of the Hand2 locus), and T4 ligation.