Nucleosomal asymmetry shapes histone mark binding and promotes poising at bivalent domains.

Promoters of developmental genes in embryonic stem cells (ESCs) are marked by histone H3 lysine 4 trimethylation (H3K4me3) and H3K27me3 in an asymmetric nucleosomal conformation, with each sister histone H3 carrying only one of the two marks. These bivalent domains are thought to poise genes for timely activation upon differentiation. Here, we show that asymmetric bivalent nucleosomes recruit repressive H3K27me3 binders but fail to enrich activating H3K4me3 binders, thereby promoting a poised state.

Aftermath of the Parkland Shooting: A Case Report of Post-traumatic Stress Disorder in an Adolescent Survivor.

The Journal of Child and Family Studies states that there have been more mass shootings within the last 18 years than in the entire 20th century combined, with 77% carried out by adolescents. This case study aims to evaluate the clinical presentation of post-traumatic stress disorder (PTSD) in an adolescent by highlighting the clinical course of a school shooting survivor. Here, we present the case of a 15-year-old female who presented to the emergency department (ED) of the University Hospital Medical Center (UHMC) under the Baker Act by the police for self-injury and self-harm.

DNA Methylation Directs Polycomb-Dependent 3D Genome Re-organization in Naive Pluripotency.

The DNA hypomethylation that occurs when embryonic stem cells (ESCs) are directed to the ground state of naive pluripotency by culturing in two small molecule inhibitors (2i) results in redistribution of polycomb (H3K27me3) away from its target loci. Here, we demonstrate that 3D genome organization is also altered in 2i, with chromatin decompaction at polycomb target loci and a loss of long-range polycomb interactions. By preventing DNA hypomethylation during the transition to the ground state, we are able to restore to ESC in 2i the H3K27me3 distribution, as well as polycomb-mediated 3D genome organization that is characteristic of primed ESCs grown in serum.