Project description:Epigenetic control of gene expression occurs within discrete spatial chromosomal units called topologically associating domains (TADs), but the exact spatial requirements of most genes are unknown; this is of particular interest for genes involved in cancer. We therefore applied high-resolution chromosomal conformation capture-sequencing to map the three-dimensional (3D) organization of the human locus encoding the key myeloid transcription factor PU.1 in healthy monocytes and acute myeloid leukemia (AML) cells. We identified a dynamic ~75kb unit (SubTAD) as the genomic region in which spatial interactions between PU.1 gene regulatory elements occur during myeloid differentiation and are interrupted in AML. Within this SubTAD, proper initiation of the spatial chromosomal interactions requires PU.1 autoregulation and recruitment of the chromatin-adaptor protein LDB1 (LIM domain-binding protein 1). However, once these spatial interactions have occurred, LDB1 stabilizes them independently of PU.1 auto-regulation. Thus, our data support that PU.1 auto-regulates its expression in a ‘hit-and-run’ manner by initiating stable chromosomal loops that result in a transcriptionally active chromatin architecture.
Project description:Epigenetic control of gene expression occurs through discrete spatial chromosomal units called topologically associating domains (TADs), but the exact spatial requirements of most genes are unknown; this is of particular interest for genes involved in disease. We therefore applied high-resolution chromosomal conformation capture-sequencing to map the three-dimensional (3D) organization of the locus encoding the key myeloid transcription factor PU.1 in healthy monocytes and acute myeloid leukemia (AML) cells. We identified a dynamic ~75kb unit (SubTAD) as the genomic region in which spatial interactions between PU.1 gene regulatory elements occur during myeloid differentiation and are interrupted in AML. Within this SubTAD, initiating the spatial chromosomal interactions requires PU.1 auto-regulation and recruitment of the chromatin-adaptor protein LDB1 (LIM domain-binding protein 1). However, once formed, this SubTAD remains stable even when auto-regulation is impaired. Thus, our data support that PU.1 auto-regulation functions in a ‘hit-and-run’ manner, whereby it organizes chromosomal loops to create a transcriptionally active chromatin architecture.
