Similar Datasets
Project description:Cohesin organizes the genome through the formation of chromatin loops. NIPBL activates cohesin's ATPase and is essential for loop extrusion, but its requirement for cohesin loading is unclear. Here we have examined the effect of reducing NIPBL levels on the behavior of the two cohesin variants carrying STAG1 or STAG2 by combining a flow cytometry assay to measure chromatin-bound cohesin with analyses of its genome-wide distribution and genome contacts. We show that NIPBL depletion results in increased cohesin-STAG1 on chromatin that further accumulates at CTCF positions while cohesin-STAG2 diminishes genome-wide. Our data are consistent with a model in which NIPBL may not be required for chromatin association of cohesin but it is for loop extrusion, which in turn facilitates stabilization of cohesin-STAG2 at CTCF positions after being loaded elsewhere. In contrast, cohesin-STAG1 binds chromatin and becomes stabilized at CTCF sites even under low NIPBL levels, but genome folding is severely impaired.
| S-EPMC10006224 | biostudies-literature
Project description:Cohesin mediates sister chromatid cohesion and organizes the genome through the formation of chromatin loops. Two versions of the complex carrying either STAG1 or STAG2 show overlapping and specific functions and both are required to fulfill embryonic development. Cohesin-STAG1 displays longer residence time on chromatin that depends on CTCF and ESCO1 and establishes longer, long-lived chromatin loops together with CTCF. Cohesin-STAG2 shows a preferential interaction with WAPL and mediates shorter loops involved in tissue-specific transcription independently of CTCF. Here we show that the two variants respond in opposite ways to knock down of NIPBL, the putative cohesin loader that is also essential for loop extrusion. Cohesin-STAG1 levels increase on chromatin under this condition and the complex accumulates further at CTCF positions while cohesin-STAG2 is diminished genome-wide. Our data support a model in which NIPBL is not required for association of cohesin with chromatin but it is for loop extrusion, which in turn facilitates stabilization of cohesin-STAG2 at CTCF positions after being loaded elsewhere. In contrast, cohesin-STAG1 is preferentially loaded at CTCF sites independently of NIPBL. Nevertheless, loop formation by these chromatin-bound complexes is impaired and gene expression is severely affected, resembling alterations in Cornelia de Lange patients
2023-01-30 | GSE207115 | GEO
Project description:Cohesin mediates sister chromatid cohesion and organizes the genome through the formation of chromatin loops. Two versions of the complex carrying either STAG1 or STAG2 show overlapping and specific functions and both are required to fulfill embryonic development. Cohesin-STAG1 displays longer residence time on chromatin that depends on CTCF and ESCO1 and establishes longer, long-lived chromatin loops together with CTCF. Cohesin-STAG2 shows a preferential interaction with WAPL and mediates shorter loops involved in tissue-specific transcription independently of CTCF. Here we show that the two variants respond in opposite ways to knock down of NIPBL, the putative cohesin loader that is also essential for loop extrusion. Cohesin-STAG1 levels increase on chromatin under this condition and the complex accumulates further at CTCF positions while cohesin-STAG2 is diminished genome-wide. Our data support a model in which NIPBL is not required for association of cohesin with chromatin but it is for loop extrusion, which in turn facilitates stabilization of cohesin-STAG2 at CTCF positions after being loaded elsewhere. In contrast, cohesin-STAG1 is preferentially loaded at CTCF sites independently of NIPBL. Nevertheless, loop formation by these chromatin-bound complexes is impaired and gene expression is severely affected, resembling alterations in Cornelia de Lange patients
2023-01-30 | GSE207110 | GEO
Project description:Cohesin mediates sister chromatid cohesion and organizes the genome through the formation of chromatin loops. Two versions of the complex carrying either STAG1 or STAG2 show overlapping and specific functions and both are required to fulfill embryonic development. Cohesin-STAG1 displays longer residence time on chromatin that depends on CTCF and ESCO1 and establishes longer, long-lived chromatin loops together with CTCF. Cohesin-STAG2 shows a preferential interaction with WAPL and mediates shorter loops involved in tissue-specific transcription independently of CTCF. Here we show that the two variants respond in opposite ways to knock down of NIPBL, the putative cohesin loader that is also essential for loop extrusion. Cohesin-STAG1 levels increase on chromatin under this condition and the complex accumulates further at CTCF positions while cohesin-STAG2 is diminished genome-wide. Our data support a model in which NIPBL is not required for association of cohesin with chromatin but it is for loop extrusion, which in turn facilitates stabilization of cohesin-STAG2 at CTCF positions after being loaded elsewhere. In contrast, cohesin-STAG1 is preferentially loaded at CTCF sites independently of NIPBL. Nevertheless, loop formation by these chromatin-bound complexes is impaired and gene expression is severely affected, resembling alterations in Cornelia de Lange patients
2023-01-30 | GSE207113 | GEO
Project description:Response of cohesin STAG1 and STAG2 to reduction of NIPBL levels
| PRJNA853750 | ENA
Project description:Response of cohesin STAG1 and STAG2 to reduction of NIPBL levels [Hi-C]
| PRJNA853742 | ENA
Project description:Response of cohesin STAG1 and STAG2 to reduction of NIPBL levels [RNA-Seq]
| PRJNA853746 | ENA
Project description:Response of cohesin STAG1 and STAG2 to reduction of NIPBL levels [ChIP-Seq]
| PRJNA853744 | ENA
Project description:The cohesin subunit STAG2 has emerged as a recurrently inactivated tumor suppressor in human cancers. Using candidate approaches, recent studies have revealed a synthetic lethal interaction between STAG2 and its paralog STAG1 To systematically probe genetic vulnerabilities in the absence of STAG2, we have performed genome-wide CRISPR screens in isogenic cell lines and identified STAG1 as the most prominent and selective dependency of STAG2-deficient cells. Using an inducible degron system, we show that chemical genetic degradation of STAG1 protein results in the loss of sister chromatid cohesion and rapid cell death in STAG2-deficient cells, while sparing STAG2-wild-type cells. Biochemical assays and X-ray crystallography identify STAG1 regions that interact with the RAD21 subunit of the cohesin complex. STAG1 mutations that abrogate this interaction selectively compromise the viability of STAG2-deficient cells. Our work highlights the degradation of STAG1 and inhibition of its interaction with RAD21 as promising therapeutic strategies. These findings lay the groundwork for the development of STAG1-directed small molecules to exploit synthetic lethality in STAG2-mutated tumors.
| S-EPMC7266993 | biostudies-literature
Project description:Cohesin is a multiprotein complex made up of core subunits Smc1, Smc3, and Rad21, and either Stag1 or Stag2. Normal haematopoietic development relies on crucial functions of cohesin in cell division and regulation of gene expression via three-dimensional chromatin organization. Cohesin subunit STAG2 is frequently mutated in myeloid malignancies, but the individual contributions of Stag variants to haematopoiesis or malignancy are not fully understood. Zebrafish have four Stag paralogues (Stag1a, Stag1b, Stag2a, and Stag2b), allowing detailed genetic dissection of the contribution of Stag1-cohesin and Stag2-cohesin to development. Here we characterize for the first time the expression patterns and functions of zebrafish stag genes during embryogenesis. Using loss-of-function CRISPR-Cas9 zebrafish mutants, we show that stag1a and stag2b contribute to primitive embryonic haematopoiesis. Both stag1a and stag2b mutants present with erythropenia by 24 h post-fertilization. Homozygous loss of either paralogue alters the number of haematopoietic/vascular progenitors in the lateral plate mesoderm. The lateral plate mesoderm zone of scl-positive cells is expanded in stag1a mutants with concomitant loss of kidney progenitors, and the number of spi1-positive cells are increased, consistent with skewing toward primitive myelopoiesis. In contrast, stag2b mutants have reduced haematopoietic/vascular mesoderm and downregulation of primitive erythropoiesis. Our results suggest that Stag1 and Stag2 proteins cooperate to balance the production of primitive haematopoietic/vascular progenitors from mesoderm.
| S-EPMC7750468 | biostudies-literature