Transgenic Drosophila melanogaster carrying a mesodermally expressed tagged histone marker (Bonn, S., Zinzen, R.P., Perez-Gonzalez, A., Riddell, A., Gavin, A.C., and Furlong, E.E. (2012). Cell type-specific chromatin immunoprecipitation from multicellula For DNase digestion, nuclei were resuspended in R-buffer (7.5mM Tris pH8, 45mM NaCl, 30mM KCl, 6mM MgCl2, 1mM CaCl2). Nuclei (4-20x10e6 per digest) were digested in 500uL R-buffer containing 2-20 units of DNaseI depending on nuclei number (where possible