GSE169105
M1BP cooperates with CP190 to activate transcription at TAD borders and promote chromatin insulator activity (ATAC-seq)
Genome organization is driven by forces affecting transcriptional state, but the relationship between transcription and genome architecture remains unclear. Here, we identified the Drosophila transcription factor Motif 1 Binding Protein (M1BP) in physical association with the gypsy chromatin insulator core complex, including the universal insulator protein CP190. M1BP is required for enhancer-blocking and barrier activities of the gypsy insulator as well as its proper nuclear localization. Genome-wide, M1BP specifically colocalizes with CP190 at Motif 1-containing promoters, which are enriched at topologically associating domain (TAD) borders. M1BP is required for CP190 chromatin binding at many shared sites, and CP190 also affects M1BP chromatin association. Both factors are required for Motif 1-dependent gene expression and transcription near TAD borders genome-wide. Finally, loss of M1BP alters local genome compaction. Our results reveal physical and functional interaction between CP190 and M1BP to activate transcription at TAD borders and mediate chromatin insulator-dependent genome organization. Overall design: Examination of overlapping of M1BP with insulator protein CP190 genome wide in Kc167 embryonic cell lines and also to investigate whether association of these insulator factors are dependent on M1BP or binding of M1BP dependent on CP190. Overall, both M1BP and CP190 regulate together active transcription at TAD borders.