X-chromosome inactivation (XCI) provides a dosage compensation mechanism where, in each female cell, one of the two X chromosomes is randomly silenced. However, some genes on the inactive X chromosome and outside the pseudoautosomal regions escape from XCI and are expressed from both alleles (escapees). We investigated XCI at single-cell resolution combining deep single cellRNA sequencing with whole-genome sequencing to examine allelic-specific expression in 935 primary fibroblast and 48 lymphoblastoid single cells from five female individuals. In this framework we integrated an original method to identify and exclude doublets of cells. In fibroblast cells, we have identified 55 genes as escapees including five novel escapee genes. Moreover, we observed that all genes exhibit a variable propensity to escape XCI in each cell and cell type and that each cell displays a distinct expression profile of the escapee genes. A metric, the Inactivation Score—defined as the mean of the allelic expression profiles of the escapees per cell—enables us to discover a heterogeneous and continuous degree of cellular XCI with extremes represented by “inactive” cells, i.e., cells exclusively expressing the escaping genes from the active X chromosome and “escaping” cells expressing the escapees from both alleles. We found that this effect is associated with cell-cycle phases and, independently, with the XIST expression level, which is higher in the quiescent phase (G0). Single-cell allele-specific expression is a powerful tool to identify novel escapees in different tissues and provide evidence of an unexpected cellular heterogeneity of XCI. Overall design: Single-cell RNA seq study on 935 human fibroblasts and 48 lymphoblastoid cells from 5 female individuals, in order to investigate the X chromosome nactivation mechanism on a single cell level and to identify escapee genes
Single cell transcriptome in aneuploidies reveals mechanisms of gene dosage imbalance.
Specimen part, Subject
View SamplesDown syndrome (DS) results from trisomy of chromosome 21 (HSA21). Some DS phenotypes may be directly or indirectly related to the increased expression of specific HSA21 genes, in particular those encoding transcription factors. The HSA21 encoded Single-minded 2 (SIM2) transcription factor has key neurological functions and is a good candidate to be involved in the cognitive impairment of DS. ChIP-sequencing was used to map SIM2 binding in mouse embryonic stem cells and has revealed 1229 high-confidence SIM2-binding sites. Analysis of the SIM2 target genes confirmed the importance of SIM2 in developmental and neuronal processes and indicated that SIM2 may be a master transcription regulator. Indeed, SIM2 DNA binding sites share sequence specificity and overlapping domains of occupancy with master transcription factors such as SOX2, OCT4, NANOG or KLF4. The association between SIM2 and these pioneer factors is supported by the finding that SIM2 can be co-immunoprecipitated with SOX2, OCT4, NANOG or KLF4. Furthermore, the binding of SIM2 marks a particular sub-category of enhancers known as super-enhancers. These regions are characterized by typical DNA modifications and Mediator co-occupancy (MED1 and MED12). Altogether, we provide evidence that SIM2 binds a specific set of enhancer elements thus explaining how SIM2 can regulate its gene network in DS neuronal features. Overall design: RNA-Seq analysis in Sim2 expressing cells (3 replicates A6, B8, C4) and EB3 control cells (3 replicates)
HSA21 Single-Minded 2 (Sim2) Binding Sites Co-Localize with Super-Enhancers and Pioneer Transcription Factors in Pluripotent Mouse ES Cells.
No sample metadata fields
View SamplesP1 encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize silks and red phlobaphene pigments in pericarps and other floral tissues, which contributed to making P1 an important visual marker since the dawn of modern genetics. We conducted RNA-Seq using pericarps at two different stages, 14 and 25 days after pollination (DAP). High-throughput sequencing using the Illumina platform resulted in the generation of ~20 million high quality reads, from which ~90% aligned to the recently completed maize genome sequence corresponding to ~5 million reads for each one of the four samples. Overall design: Examination of two different RNA samples from two different stages of maize pericarp tissues.
A genome-wide regulatory framework identifies maize pericarp color1 controlled genes.
Specimen part, Subject
View SamplesP1 encodes an R2R3-MYB transcription factor responsible for the accumulation of insecticidal flavones in maize silks and red phlobaphene pigments in pericarps and other floral tissues, which contributed to making P1 an important visual marker since the dawn of modern genetics. We conducted RNA-Seq using from maize silks obtained at 2-3 days after emergence. High-throughput sequencing using the Illumina platform resulted in the generation of ~14 million high quality reads, corresponding to ~7 million reads for each sample, from which 76% aligned to the maize genome. Overall design: Examination of two different RNA samples from maize silks obtained at 2-3 days after emergence
A genome-wide regulatory framework identifies maize pericarp color1 controlled genes.
Specimen part, Subject
View SamplesBackground: Eukaryotic cells express a complex layer of noncoding RNAs. An intriguing family of regulatory RNAs includes transcripts from the opposite strand of protein coding genes, so called natural antisense transcripts (NATs). Here, we test the hypothesis that antisense transcription triggers RNA interference and gives rise to endogenous short RNAs (endo-siRNAs). Methods/Results: We used cloned human embryonic kidney cells (HEK293) followed by short RNAseq to investigate the small genic RNA transcriptome. 378 genes gave rise to short RNA reads that mapped to exons of RefSeq genes. The length profile of short RNAs showed a broad peak of 20-24 nucleotides, indicative of endo-siRNAs. Collapsed reads mapped predominantly to the first and the last exon of genes (74%). RNAs reads were intersected with sequences occupied by RNAPolII or bound to Argonaute (AGO1 by crosslinking, ligation, and sequencing of hybrids, CLASH). In the first exon, 94% of the reads correlated with PolII occupancy with an average density of 130 (relative units); this decreased to 65%/20 in middle exons and 54%/12 in the last exon. CLASH reads mapping to multi-exon genes showed little distribution bias with an average of about 5 CLASH reads overlapping with 60% of the endo-siRNA reads. However, endo-siRNAs (21-25 nt) intersecting with CLASH reads were enriched at the 5''end and decreased towards the 3''end. We then investigated the 378 genes with particular focus on features indicative for short RNA production; however, found that endo-siRNA numbers did not correlate with gene structures that favor convergent transcription. In contrast, our gene set was found notably over-represented in the NATsDB sense/antisense group as compared to non-overlapping and non-bidirectional groups. Moreover, read counts showed no correlation with the steady-state levels of the related mRNAs and the pattern of endo-siRNAs proved reproducible after an induced mutagenic insult. Conclusions: Our results suggest that antisense transcripts contribute to low levels of endo-siRNAs in fully differentiated human cells. A characteristic endo-siRNA footprint is being produced at sites of RNAPolII transcription which is also related to AGO1. This endo-siRNA signature represents an intriguing finding and its reproducibility suggests that the production of endo-siRNAs is a regulated process with potential homoeostatic impact. Overall design: Size selected RNASeq of 3 human embryonic kidney cell (HEK293) samples. 1 control and 2 samples exposed to 100 µg/ml ethyl methanesulfonate for 24 hrs.
Contribution of natural antisense transcription to an endogenous siRNA signature in human cells.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Brain transcriptional and epigenetic associations with autism.
Age, Specimen part, Disease, Disease stage, Subject
View SamplesAutism is a common neurodevelopmental syndrome. Numerous rare genetic etiologies are reported; most cases are idiopathic. To uncover important gene dysregulation in autism we analyzed carefully selected idiopathic autistic and control cerebellar and BA19 (occipital) brain tissues using high resolution whole genome gene expression and DNA methylation microarrays. No changes in DNA methylation were identified in autistic brain but gene expression abnormalities in two areas of metabolism were apparent: down-regulation of genes of mitochondrial oxidative phosphorylation and of protein translation. We also found associations between specific behavioral domains of autism and specific brain gene expression modules related to myelin/myelination, inflammation/immune response and purinergic signaling. This work highlights two largely unrecognized molecular pathophysiological themes in autism and suggests differing molecular bases for autism behavioral endophenotypes.
Brain transcriptional and epigenetic associations with autism.
Age
View SamplesThe oxt6 mutant is an oxidative stress-tolerant Arabidopsis mutant that is deficient in a polyadenylation factor subunit. Expression analysis suggests that impaired poly(A) site choice is responsible for the stress-tolerant phenotype.
A polyadenylation factor subunit implicated in regulating oxidative signaling in Arabidopsis thaliana.
No sample metadata fields
View SamplesTranscription profiling of Arabidopsis mutant ron1-1 vs the wild type Ler
The RON1/FRY1/SAL1 gene is required for leaf morphogenesis and venation patterning in Arabidopsis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genetic correction of human induced pluripotent stem cells from patients with spinal muscular atrophy.
Specimen part
View Samples