Olfactory sensory neurons express just one out of a possible ~1000 odorant receptor genes, reflecting an exquisite mode of gene regulation. In one model, once an odorant receptor is chosen for expression, other receptor genes are suppressed by a negative feedback mechanism, ensuring a stable functional identity of the sensory neuron for the lifetime of the cell. The signal transduction mechanism subserving odorant receptor gene silencing remains obscure, however. Here we demonstrate in the zebrafish that odorant receptor gene silencing is dependent on receptor activity. Moreover, we show that signaling through G protein ß? subunits is both necessary and sufficient to suppress the expression of odorant receptor genes, and likely acts through histone methylation to maintain the silenced odorant receptor genes in transcriptionally inactive heterochromatin. These results provide new insights linking receptor activity with the epigenetic mechanisms responsible for ensuring the expression of one odorant receptor per olfactory sensory neuron. Overall design: Total 6 samples were analyzed-3 controls & 3 samples
Normalization of RNA-seq data using factor analysis of control genes or samples.
No sample metadata fields
View SamplesMidbrain dopamine neurons project to numerous targets throughout the brain to modulate various behaviors and brain states. Within this small population of neurons exists significant heterogeneity based on physiology, circuitry, and disease susceptibility. Recent studies have shown that dopamine neurons can be subdivided based on gene expression; however, the extent to which genetic markers represent functionally relevant dopaminergic subpopulations has not been fully explored. Here we performed single-cell RNA-sequencing of mouse dopamine neurons and validated studies showing that Neurod6 and Grp are selective markers for dopaminergic subpopulations. Using a combination of multiplex fluorescent in situ hybridization, retrograde labeling, and electrophysiology in mice of both sexes, we defined the anatomy, projection targets, physiological properties, and disease vulnerability of dopamine neurons based on Grp and/or Neurod6 expression. We found that the combinatorial expression of Grp and Neurod6 defines dopaminergic subpopulations with unique features. Grp/Neurod6 dopamine neurons reside in the ventromedial VTA, send projections to the medial shell of the nucleus accumbens, and have noncanonical physiological properties. Grp/Neurod6- DA neurons are found in the VTA as well as in the ventromedial portion of the SNc, where they project selectively to the dorsomedial striatum. Grp-/Neurod6 DA neurons represent a smaller VTA subpopulation, which is preferentially spared in a 6-OHDA model of Parkinson's disease. Together, our work provides detailed characterization of Neurod6 and Grp expression in the midbrain and generates new insights into how these markers define functionally relevant dopaminergic subpopulations with distinct projection patterns, physiology, and disease vulnerability. Overall design: We collected a total of 384 neurons from 8 different p26-p34 DAT-Cre::Ai9 mice (6 male 2 female) to isolate DA neurons. RNA was captured from each samples neurons on separate fluidigm chips then all samples were pooled before sequencing.
Combinatorial Expression of <i>Grp</i> and <i>Neurod6</i> Defines Dopamine Neuron Populations with Distinct Projection Patterns and Disease Vulnerability.
Sex, Specimen part, Cell line, Subject
View SamplesWhy we sleep is still one of the most perplexing mysteries in biology. Strong evidence, however, indicates that sleep is necessary for normal brain function and that the need to sleep is a tightly regulated process. Surprisingly molecular mechanisms that determine the need to sleep are incompletely described. Moreover, very little is known about transcriptional changes that specifically accompany the accumulation and discharge of sleep need.
Removal of unwanted variation reveals novel patterns of gene expression linked to sleep homeostasis in murine cortex.
Sex, Age, Specimen part
View SamplesProgrammable nucleases have enabled rapid and accessible genome engineering in eukaryotic cells and living organisms. However, their delivery into target cells can be technically challenging when working with primary cells or in vivo. Using engineered murine leukemia virus-like particles loaded with Cas9/sgRNA ribonucleoproteins (“Nanoblades”), we were able to induce efficient genome-editing in cell lines and primary cells including human induced pluripotent stem cells, human hematopoietic stem cells and mouse bone-marrow cells. Transgene-free Nanoblades were also capable of in vivo genome-editing in mouse embryos and in the liver of injected mice. Nanoblades can be complexed with donor DNA for “all-in-one” homology-directed repair or programmed with modified Cas9 variants to mediate transcriptional up-regulation of target genes. Nanoblades preparation process is simple, relatively inexpensive and can be easily implemented in any laboratory equipped for cellular biology. Overall design: Virus-like particles were purified on a sucrose cushion. Total RNA was extracted using Trizol and fragmented to ~100 nucleotides and used as input for cDNA library preparation. PCR-amplified libraries were sequenced on the Hiseq2500 platform (Illumina)
Genome editing in primary cells and in vivo using viral-derived Nanoblades loaded with Cas9-sgRNA ribonucleoproteins.
Cell line, Subject
View SamplesThe miR-16 family, which targets genes important for the G1-S transition, is a known modulator of the cell cycle, and members of this family are often deleted or down-regulated in many types of cancers. Here we report the reciprocal relationship - that of the cell cycle controlling the miR-16 family. Levels of this family increase rapidly as cells are arrested in G0. Conversely, as cells are released from G0 arrest, levels of the miR-16 family rapidly decrease. Such rapid changes are made possible by the unusual instabilities of several family members. The repression mediated by the miR-16 family is sensitive to these cell cycle changes, which suggests that the rapid up-regulation of the miR-16 family reinforces cell cycle arrest in G0. Upon cell cycle re-entry, the rapid decay of several members allows levels of the family to decrease, alleviating repression of target genes and allowing proper resumption of the cell cycle. Overall design: Small RNAs were profiled by high-throughput sequencing either during synchronous release after serum starvation or during cell-cycle arrest by contact inhibition.
MicroRNA destabilization enables dynamic regulation of the miR-16 family in response to cell-cycle changes.
Specimen part, Cell line, Subject
View SamplesTranslation and mRNA decay are intimately connected processes, and translational inhibition often precedes and stimulates transcript degradation. Here, we have focused on methods that allow determination of mRNA stability on a transcriptome-wide scale. We describe experimental and computational methods for the two most commonly used approaches (transcriptional inhibition and metabolic labeling), and we discuss associated caveats. Overall design: Metabolic labeling time courses (1, 2, 4, 8, 12, 24 hr) using 4SU were performed in HEK293.
Determining mRNA half-lives on a transcriptome-wide scale.
Treatment, Subject
View SamplesMouse embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) exhibit a pluripotent developmental potential, contributing to all embryonic cell types, though rarely to extra-embryonic lineages. Unexpectedly, rare, totipotent-like stem cells have been identified in cultured ESC populations, suggesting the existence of a discrete molecular pathway that regulates the transition between totipotency and pluripotency in vitro. Here, we identify a single miRNA, miR-34a, whose deficiency in mouse pluripotent stem cells expands cell fate potential, giving rise to both embryonic and extra-embryonic lineages in vitro and in vivo. The expression profiles of the totipotent-like miR-34a-knockout murine pluripotent stem cells are characterized by a strong induction of MERVL endogenous retroviruses, a key molecular hallmark shared with totipotent mouse 2-cell blastomeres and totipotent-like mouse ESCs. In all three cell types, a subset of MERVL elements promotes the expression of specific isoforms of the proximal protein-coding genes. We demonstrate that miR-34a represses MERVL expression through transcriptional regulation, at least in part, by directly targeting the transcription factor GATA-binding protein 2 (Gata2). Since MERVL activation correlated precisely with the totipotent-like state, we hypothesized that the miR-34a/Gata2 pathway that regulates MERVL expression in ESCs/iPSCs also regulates the acquisition of totipotency in culture. Consistent with this hypothesis, gata2 knock-down in miR-34a-knockout mouse pluripotent stem cells not only reduced MERVL expression, but also abolished the expanded cell fate potential of these cells both in vitro and in vivo. Taken together, our findings not only provide key insights into the functional importance of miR-34a in restricting the totipotent cell fate potential of pluripotent stem cells, but also elucidate the underlying molecular basis by which miR-34a regulates the developmental potentials of ESCs/iPSCs. Overall design: Wildtype and miR-34a-deficient iPSCs, three biological replicates per group
Deficiency of microRNA <i>miR-34a</i> expands cell fate potential in pluripotent stem cells.
No sample metadata fields
View SamplesThe purpose of this study was to search for microgravity-sensitive genes, specifically for apoptotic genes influenced by the microgravity environment and other genes related to immune response.
Gene expression alterations in activated human T-cells induced by modeled microgravity.
No sample metadata fields
View SamplesThe lineage of the horizontal basal cells (HBC) stem cells and other Sox2eGFP-positive cells from the olfactory epithelium were profiled by single-cell RNA-Seq to identify differentiated cells types, intermediate stages, transition states, and to infer the lineage trajectories. Overall design: Horizontal basal cell (HBC) stem cells from the olfactory epithelium that were either wild-type or mutant for the transcription factor Trp63/p63 were lineage traced, collected by FACS, and profiled by single-cell RNA-seq. Additionally, Sox2eGFP transgenic cells from the olfactory epithelium were combined with this data into one data set that was processed together. A minimum of two biological replicates were collected for each time-point/experimental condition. A total of 680 YFP-positive lineage traced cells plus 169 Sox2eGFP-positive cells were used in this analysis.
Deconstructing Olfactory Stem Cell Trajectories at Single-Cell Resolution.
Subject
View SamplesThe below table includes a smaller list of data that was analyzed by dChip and filtered by pvalue such that a file with about 4600 genes was obtained, which allowed for ease of use from 40,000 genes.
Identification of mechanosensitive genes in osteoblasts by comparative microarray studies using the rotating wall vessel and the random positioning machine.
Specimen part
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