Project description:Animals traversing different environments encounter both stable background stimuli and novel cues, which are thought to be detected by primary sensory neurons and then distinguished by downstream brain circuits. Here we show that each of the ~1000 olfactory sensory neuron (OSN) subtypes in the mouse harbors a distinct transcriptome whose content is precisely determined by interactions between its odorant receptor and the environment. This transcriptional variation is systematically organized to support sensory adaptation: expression levels of more than 70 genes relevant to transforming odors into spikes continuously vary across OSN subtypes, dynamically adjust to new environments over hours, and accurately predict acute OSN-specific odor responses. The sensory periphery therefore separates salient signals from predictable background via a transcriptional rheostat whose moment-to-moment state reflects the past and constrains the future; these findings suggest a general model in which structured transcriptional variation within a cell type reflects individual experience.
Project description:Neural-type specific expression of clustered Protocadherin (Pcdh) proteins is essential for the establishment of connectivity patterns during brain development. In mammals, deterministic expression of the same Pcdh isoform promotes minimal overlap of tiled projections of serotonergic neuron axons throughout the brain, while stochastic expression of Pcdh genes allows for convergence of tightly packed overlapping olfactory sensory neuron axons into targeted structures. How can the same gene locus generate opposite transcriptional programs that orchestrate distinct spatial arrangements of axonal patterns? Here, we reveal that cell-type specific Pcdh expression and axonal behavior rest on the activity of cohesin and its unloader WAPL. While cohesin erases genomic-distance biases in Pcdh choice, WAPL functions as a rheostat of cohesin processivity that determines Pcdh isoform diversity.
Project description:Neuronal activity-dependent transcription couples sensory experience to adaptive responses of the brain including learning and memory. Mechanisms of activity-dependent gene expression including alterations of the epigenome have been characterized. However, the fundamental question of whether and how sensory experience remodels chromatin architecture in the adult brain in vivo to induce neural code transformations and learning and memory remains to be addressed. Here, in vivo calcium imaging, optogenetics, and pharmacological approaches reveal that granule neuron activation in the anterior dorsal cerebellar vermis (ADCV) plays a crucial role in a novel delay tactile startle learning paradigm in mice. Strikingly, using large-scale transcriptome and chromatin profiling, we have discovered that activation of the motor learning-linked granule neuron circuit reorganizes neuronal chromatin including through long-distance enhancer-promoter and transcriptionally active compartment interactions to orchestrate distinct granule neuron gene expression modules. Conditional CRISPR knockout of the chromatin architecture regulator Cohesin in ADCV granule neurons in adult mice disrupts activity-dependent transcription and motor learning. These findings define how sensory experience patterns chromatin architecture and neural circuit coding in the brain to drive motor learning.
Project description:This SuperSeries is composed of the following subset Series: GSE38305: Promoter DNA methylation couples genome-defense mechanisms to epigenetic reprogramming in the mouse germline (part 1) GSE38306: Promoter DNA methylation couples genome-defence mechanisms to epigenetic reprogramming in the mouse germline (part 2) Refer to individual Series
Project description:Nuclear remodeling to an extreme condensed state is a hallmark of spermatogenesis. This is achieved by varied degrees of replacement of histones with protamines. Regions retaining nucleosomes may be of functional significance. To determine potential roles for somatic-like chromatin in the paternal gamete, sperm from wild type and transgenic mice harboring a single copy insert of the human protamine cluster were subjected to Micrococcal Nuclease (MNase)-seq. Nuclease footprints linked robust endogenous protamine transcription and transgene suppression to its chromatin environment. Murine footprints were enriched within regulatory regions and sequences expressed in the early embryo. These were highlighted by Ctcf footprints that were enriched within chromatin domain boundaries and sites bound in testes and ESCs. In contrast, Ctcf footprints were absent in human and bull sperm. The continuity of Ctcf binding through the murine germline may permit rapid reconstitution of chromatin organization following fertilization. This likely reflects its preparation for early zygotic genome activation and comparatively accelerated preimplantation embryonic development program observed in mouse as compared to human.
Project description:The Illumina Infinium MethylationEPIC Beadchip was used to obtain genomewide methylation profiles of 16 human couples (32 individuals), selected by their facial resemblance.