MCF-7 as a model for functional analysis of breast cancer risk variants
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE130852 | GEO | 2019/05/09
REPOSITORIES: GEO
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Project description:The ubiquitously expressed transcription factor CTCF maintains higher-order chromatin structure in multiple cell types and species through well-established common mechanisms. Here we define a new role for CTCF in tissue-specific gene regulation revealed by serial examinations of genome-wide CTCF occupancy during red blood cell (RBC) differentiation of human CD34+ hematopoietic stem/progenitor cells (HSPCs). We identified 1753 dynamic, erythroid developmental stage-specific CTCF chromatin occupancy sites that occur through both direct DNA binding and indirectly via interactions with lineage-specific transcription factors. These dynamic sites display features of transcriptional enhancers, function as hubs of cis-regulatory elements (CREs) interactome, and are enriched for single nucleotide polymorphisms (SNPs) associated with RBC traits. Precise deletion of CTCF binding motifs from those dynamically bound sites alternated local CRE-interactions and disrupted erythropoiesis. Our study highlights novel, lineage-specific functions for CTCF and provides new insights into how genetic variation regulates erythropoiesis
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Project description:The ubiquitously expressed transcription factor CTCF maintains higher-order chromatin structure in multiple cell types and species through well-established common mechanisms. Here we define a new role for CTCF in tissue-specific gene regulation revealed by serial examinations of genome-wide CTCF occupancy during red blood cell (RBC) differentiation of human CD34+ hematopoietic stem/progenitor cells (HSPCs). We identified 1753 dynamic, erythroid developmental stage-specific CTCF chromatin occupancy sites that occur through both direct DNA binding and indirectly via interactions with lineage-specific transcription factors. These dynamic sites display features of transcriptional enhancers, function as hubs of cis-regulatory elements (CREs) interactome, and are enriched for single nucleotide polymorphisms (SNPs) associated with RBC traits. Precise deletion of CTCF binding motifs from those dynamically bound sites alternated local CRE-interactions and disrupted erythropoiesis. Our study highlights novel, lineage-specific functions for CTCF and provides new insights into how genetic variation regulates erythropoiesis
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Project description:CTCF is an architectural protein with a critical role in connecting higher-order chromatin folding in pluripotent stem cells. Recent reports have suggested that CTCF binding is more dynamic during development than previously appreciated. Here we set out to understand the extent to which shifts in genome-wide CTCF occupancy contribute to the 3-D reconfiguration of fine-scale chromatin folding during early neural lineage commitment. Unexpectedly, we observe a sharp decrease in CTCF occupancy during the transition from naïve/primed pluripotency to multipotent primary neural progenitor cells (NPCs). Many pluripotency gene-enhancer interactions are anchored by CTCF and its occupancy is lost in parallel with loop decommissioning during differentiation. Conversely, CTCF binding sites in NPCs are largely pre-existing in pluripotent stem cells. Only a small number of CTCF sites arise de novo in NPCs. We identify another zinc finger protein, Yin Yang 1 (YY1), at the base of looping interactions between NPC-specific genes and enhancers. Putative NPC-specific enhancers exhibit strong YY1 signal when engaged in 3-D contacts and negligible YY1 signal when not in loops. Moreover, siRNA knockdown of YY1 specifically disrupts interactions between key NPC enhancers and their target genes. YY1-mediated interactions between NPC regulatory elements are often nested within constitutive loops anchored by CTCF. Together, our results support a model in which YY1 acts as an architectural protein to connect developmentally regulated looping interactions; the location of YY1-mediated interactions may be demarcated in development by a pre-existing topological framework created by constitutive CTCF-mediated interactions.
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