Resolution of transcription-induced hexasome-nucleosome complexes by Chd1 and FACT.

To maintain the nucleosome organization of transcribed genes, ATP-dependent chromatin remodelers collaborate with histone chaperones. Here, we show that at the 5' ends of yeast genes, RNA polymerase II (RNAPII) generates hexasomes that occur directly adjacent to nucleosomes. The resulting hexasome-nucleosome complexes are then resolved by Chd1.

Histone H1 binding to nucleosome arrays depends on linker DNA length and trajectory.

Throughout the genome, nucleosomes often form regular arrays that differ in nucleosome repeat length (NRL), occupancy of linker histone H1 and transcriptional activity. Here, we report cryo-EM structures of human H1-containing tetranucleosome arrays with four physiologically relevant NRLs. The structures show a zig-zag arrangement of nucleosomes, with nucleosomes 1 and 3 forming a stack.

Structural basis of nucleosome transcription mediated by Chd1 and FACT.

Efficient transcription of RNA polymerase II (Pol II) through nucleosomes requires the help of various factors. Here we show biochemically that Pol II transcription through a nucleosome is facilitated by the chromatin remodeler Chd1 and the histone chaperone FACT when the elongation factors Spt4/5 and TFIIS are present. We report cryo-EM structures of transcribing Saccharomyces cerevisiae Pol II-Spt4/5-nucleosome complexes with bound Chd1 or FACT.

Extrapulmonary infection in patients with CARD9 deficiency.

Invasive pulmonary aspergillosis is a life-threatening mycosis that only affects patients with immunosuppression, chemotherapy-induced neutropenia, transplantation, or congenital immunodeficiency. We studied the clinical, genetic, histological, and immunological features of 2 unrelated patients without known immunodeficiency who developed extrapulmonary invasive aspergillosis at the ages of 8 and 18. One patient died at age 12 with progressive intra-abdominal aspergillosis.

Corticotropin-Releasing Hormone Receptor Type 1 (CRHR1) Clustering with MAGUKs Is Mediated via Its C-Terminal PDZ Binding Motif.

The corticotropin-releasing hormone receptor type 1 (CRHR1) plays an important role in orchestrating neuroendocrine, behavioral, and autonomic responses to stress. To identify molecules capable of directly modulating CRHR1 signaling, we performed a yeast-two-hybrid screen using the C-terminal intracellular tail of the receptor as bait. We identified several members of the membrane-associated guanylate kinase (MAGUK) family: postsynaptic density protein 95 (PSD95), synapse-associated protein 97 (SAP97), SAP102 and membrane associated guanylate kinase, WW and PDZ domain containing 2 (MAGI2).

Pathogenic fungi regulate immunity by inducing neutrophilic myeloid-derived suppressor cells.

Despite continuous contact with fungi, immunocompetent individuals rarely develop pro-inflammatory antifungal immune responses. The underlying tolerogenic mechanisms are incompletely understood. Using both mouse models and human patients, we show that infection with the human pathogenic fungi Aspergillus fumigatus and Candida albicans induces a distinct subset of neutrophilic myeloid-derived suppressor cells (MDSCs), which functionally suppress T and NK cell responses.

A novel mutation in LRSAM1 causes axonal Charcot-Marie-Tooth disease with dominant inheritance.

Background: Charcot-Marie-Tooth disease (CMT) refers to a heterogeneous group of genetic motor and sensory neuropathies. According to the primary site of damage, a distinction is made between demyelinating and axonal forms (CMT1 and 2, respectively, when inherited as an autosomal dominant trait). Leucine-rich repeat and sterile alpha motif-containing protein 1 (LRSAM1) is a ubiquitin-protein ligase with a role in sorting internalised cell-surface receptor proteins.

Encephalopathic Susac's Syndrome associated with livedo racemosa in a young woman before the completion of family planning.

Background: Susac's Syndrome (SS) consists of the triad of encephalopathy, branch retinal artery occlusions (BRAO) and hearing loss (HL). Histopathologically, SS is characterised by a microangiopathy, and some observations suggest that an immune-mediated damage of endothelial cells might play a role. These findings also implicate a similarity between SS and other autoimmune diseases, most notably juvenile dermatomyositis (JDM).

Nucleosomes can invade DNA territories occupied by their neighbors.

Nucleosomes are the fundamental subunits of eukaryotic chromatin. They are not static entities, but can undergo a number of dynamic transitions, including spontaneous repositioning along DNA. As nucleosomes are spaced close together within genomes, it is likely that on occasion they approach each other and may even collide.

Pyrosequencing positions nucleosomes precisely.

New parallel-sequencing technology has recently been used to map with unprecedented accuracy the positions of nucleosomes enriched for the histone variant H2A.Z throughout the yeast genome.

Nucleosome dynamics.

In the 30 years since the discovery of the nucleosome, our picture of it has come into sharp focus. The recent high-resolution structures have provided a wealth of insight into the function of the nucleosome, but they are inherently static. Our current knowledge of how nucleosomes can be reconfigured dynamically is at a much earlier stage.