Nuclei were isolated from cortex of mice expressing the SUN1-sfGFP-MYC nuclear membrane protein in CamkIIa-positive neurons as described in Mo A et al Neuron 2015. CamkIIa-positive nuclei were immunoprecipitated with a GFP antibody (Fisher G10362) and Protein G Dynabeads (Invitrogen). Nuclei were cross-linked in 1% formaldehyde in PBS for 10 min at room temperature, quenched with 125mM glycine for 5 min, and washed twice with PBS. Nuclei were resuspended in LB3 buffer (10 mM Tris pH 8, 100 mM NaCl, 1mM EDTA, 0.5 mM EGTA, 0.1% Na-Deoxycholate, 0.5% N-Lauroylsarcosine, protease inhibitors), and sonicated in a Diagenode Bioruptor. Insoluble material and beads were removed by spinning at 16,000g for 10 min at 4ºC, and Triton X-100 was added to soluble chromatin at a final concentration of 1%. Chromatin was pre-cleared for two hours with Protein A Dynabeads, then incubated with Protein A Dynabeads conjugated to an MeCP2 antibody overnight at 4ºC. Beads were washed twice with Low Salt Buffer (20 mM Tris pH 8, 150 mM NaCl, 2mM EDTA, 1% Triton X-100, 0.1% SDS), twice with High Salt Buffer (20 mM Tris pH 8, 500 mM NaCl, 2 mM EDTA, 1% Triton X-100, 0.1% SDS), twice with LiCl Wash Buffer (10 mM Tris pH 8, 1 mM EDTA, 1% NP-40, 250 mM LiCl, 1% sodium deoxycholate) and once with TE Buffer (50 mM Tris pH 8, 10 mM EDTA) at 4ºC. Chromatin was eluted off beads by incubating in TE Buffer with 1% SDS at 65ºC for one hour, and crosslinks were reversed by incubating overnight at 65ºC. Chromatin was treated with RNase A for 30 min at 37ºC and Proteinase K for 2 hours at 55ºC. DNA was phenol-chloroform extracted and purified with the Qiagen PCR purification kit. Libraries were generated using the NuGEN Ovation Ultralow System V2 following manufacturer instructions.