RNA from cultured pericytes, whole E14.5 brains and from neural cells was isolated using the Qiagen mini kit (#74104), while RNA from pericytes, endothelial cells and microglia was extracted using the Qiagen miRNeasy Micro kit (#1071023). Libraries for RNA-seq of cultured pericytes, whole E14.5 brains and the neural population were prepared using the Illumina TruSeq library preparation kit. For pericytes, endothelial cells and microglia, cDNA was prepared from isolated RNA using the SMART-Seq v4 Ultra Low Input RNA Kit for Sequencing (Clontech 634891). Libraries were prepared using the Nextera XT DNA library preparation kit (Illumina FC-131-1096) and sequenced on the HiSeq Hiseq 3000 or NextSeq 500. ChIP and library preparation for IP DNA was undertaken using the RELACS protocol (Arrigoni et al. 2018 Communications Biology)