mRNA expression levels were determined by NGS for wildtype larvae as well as for larvae lacking HP1a [Su(var)205^04/Su(var)205^05 transheterozygotes]. Overall design: RNA samples from wildtype (OR) and HP1a mutant third instar larvae were examined, using duplicate biological samples and Illumina NGS.
Enrichment of HP1a on Drosophila chromosome 4 genes creates an alternate chromatin structure critical for regulation in this heterochromatic domain.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Sequence-specific targeting of dosage compensation in Drosophila favors an active chromatin context.
Cell line
View SamplesThe Drosophila MSL complex mediates dosage compensation by increasing transcription of the single X chromosome in males approximately two-fold. This is accomplished through recognition of the X chromosome and subsequent acetylation of histone H4K16 on X-linked genes. Initial binding to the X is thought to occur at a subset of sites. However, the consensus sequence motif of entry sites (MSL recognition element or MRE) is only slightly enriched on the X (~2 fold), and only a fraction of them is utilized by the MSL complex. Here we ask whether chromatin context could distinguish between utilized and non-utilized copies of the motif, by comparing their relative enrichment for histone modifications and chromosomal proteins mapped in the NHGRI modENCODE project. Through a comparative analysis of the chromatin features in male S2 cells, which contain MSL complex, and female Kc cells, which lack the complex, we find that the presence of active chromatin modifications, together with an elevated local GC content in surrounding sequence, has strong predictive value for functional MSL entry sites, independent of MSL binding. We tested these sites for function in Kc cells by RNAi knockdown of Sxl, resulting in induction of MSL complex. We show that ectopic MSL expression in Kc cells leads to H4K16 acetylation around these sites, and a relative increase in X chromosome transcription. Collectively, our results support a model in which a pre-existing active chromatin environment, coincident with H3K36me3, contributes to MSL entry site selection. The consequences of MSL targeting of the male X chromosome include increase in nucleosome lability, enrichment for H4K16 acetylation and JIL-1 kinase, and depletion of linker histone H1 on active X-linked genes. Our finding serves as a model to understand how chromatin and local sequence features are involved in the selection of functional protein binding sites in the genome.
Sequence-specific targeting of dosage compensation in Drosophila favors an active chromatin context.
Cell line
View SamplesHepatocellular carcinoma (HCC) is the second most common cause of cancer related death. NAFLD affects a large proportion of the US population. Its incidence and prevalence are increasing to epidemic proportions around the world and is known to increase the risk of HCC. We studied how intrahepatic lipids affect adaptive immunity and HCC development in different murine models of NASH and HCC. Linoleic acid, a fatty acid found in NAFLD caused a selective loss of hepatic CD4+ but not CD8+ T cells leading to accelerated hepatocarcinogenesis. CD4+ T cells were more dependent on oxidative phosphorylation for energy source than CD8+ T cells, and disruption of oxidative phosphorylation by linoleic acid caused more severe damage in CD4+ T cells leading to selective loss of these cells. In vivo blockade of ROS using n-acetylcysteine reversed the NASH-induced hepatic CD4+ T cell decrease and delayed NASH-promoted HCC. Our results provide a new link between lipid metabolism and impaired anti-tumor surveillance.
NAFLD causes selective CD4(+) T lymphocyte loss and promotes hepatocarcinogenesis.
No sample metadata fields
View SamplesMSL (Male-specific lethal) complex increases transcription on the single X chromosome of Drosophila males in order to equalize expression of X-linked genes between males (XY) and females (XX). The increase in transcript levels correlates with MSL- dependent acetylation of histone H4 at K16 within the bodies of active genes, but identification of the transcriptional step affected has not been possible. In this study, we use global run-on sequencing (GRO-seq) to examine the specific effect of MSL complex on RNA Polymerase II (RNAP II) on a genome-wide level. Results indicate that MSL complex enhances transcription by facilitating the progression of RNAP II across the bodies of active X-linked genes. Improving transcriptional output downstream of typical gene-specific control may explain how dosage compensation can be imposed on the diverse set of genes along an entire chromosome. Overall design: Global Run-On Sequencing (GRO-Seq) reads, i.e., RNA-Seq of nascent RNA transcripts, from D. Melanogaster SL2 cells. Two biological replicates were analyzed.
Comprehensive analysis of the chromatin landscape in Drosophila melanogaster.
Subject
View SamplesThe conserved Mef2 transcription factor is a major regulator of gene expression and differentiation. Recent genomic studies have identified a large number of mef2-regulated target genes with distinct temporal expression profiles during Drosophila myogenesis. However, the question remains as to how a single transcription factor can control such diverse patterns of gene expression. The aim of this project was to investigate whether there are genes with different mef2-requirements for their expression during muscle differentiation in vivo during the development of Drosophila melanogaster.
mef2 activity levels differentially affect gene expression during Drosophila muscle development.
No sample metadata fields
View SamplesRNA-Sequencing of the trigeminal nucleus caudalis and spinal cord, dorsal horn in male naive rats (Wistar Han) of 10 weeks old Overall design: 6 naive rats were killed after 2 weeks of arrival, both trigeminal nucleus caudalis and spinal cord dorsal horn were dissected using laser capture microdissection of each rat.
Transcriptomic profiling of trigeminal nucleus caudalis and spinal cord dorsal horn.
No sample metadata fields
View SamplesObjectives and goals: The causes and molecular pathology of ovarian cancer are essentially unknown. However, it is generally understood that serous ovarian borderline tumors (SBOT) and well differentiated (WD) serous ovarian carcinomas (SC) have a similar tumorigenetic pathway, distinct from moderately (MD) and poorly differentiated (PD) SC. The aim of this study was to identify mRNAs differentially expressed between MD/PD SC, SBOT and superficial scrapings from normal ovaries (SNO),and to correlate these mRNAs with clinical parameters.
ZNF385B and VEGFA are strongly differentially expressed in serous ovarian carcinomas and correlate with survival.
Specimen part
View SamplesThe coupling between cell-cycle exit and onset of differentiation is a common feature throughout the developing nervous system, but the mechanisms that link these processes are mostly unknown. Although the transcription factor Pax6 was implicated in both proliferation and differentiation of multiple regions within the CNS, its contribution to the transition between these successive states remains elusive. To gain insight into the role of Pax6 during the transition from proliferating progenitors to differentiating precursors, we investigated cell-cycle and transcriptomic changes occurring in Pax6- retinal progenitor cells (RPCs). Our analyses revealed a unique cell-cycle phenotype of the Pax6-deficient RPCs, which included a reduced number of cells in the S phase, an increased number of cells exiting the cell cycle, and delayed differentiation kinetics of Pax6- precursors. These alterations were accompanied by co-expression of factors that promote (Ccnd1, Ccnd2, Ccnd3) and inhibit (P27kip1 and P27kip2) the cell cycle. Further characterization of the changes in transcription profile of the Pax6-deficient RPCs revealed abrogated expression of multiple factors which are known to be involved in regulating proliferation of RPCs, including the transcription factors Vsx2, Nr2e1, Plagl1 and Hedgehog signaling. These findings provide novel insight into the molecular mechanism mediating the pleiotropic activity of Pax6 in RPCs. The results further suggest that rather than conveying a linear effect on RPCs, such as promoting their proliferation and inhibiting their differentiation, Pax6 regulates multiple transcriptional networks which function simultaneously, thereby conferring the capacity to proliferate, assume multiple cell fates and execute the differentiation program into retinal lineages.
Pax6 is required for normal cell-cycle exit and the differentiation kinetics of retinal progenitor cells.
Specimen part
View SamplesFibroblasts synthesize the extracellular matrix of connective tissue and play an essential role in maintaining tissue integrity. We have previously shown that mouse skin connective tissue, the dermis, is comprised of functionally distinct fibroblast lineages. However, the extent of fibroblast heterogeneity in human skin is unknown. Here, using a combination of spatial transcriptional profiling of human and mouse dermis and single cell transcriptional profiling of human dermal fibroblasts, we show that there are at least four distinct fibroblast populations in adult human skin. We define markers permitting prospective isolation of these cells and show that although marker expression is rapidly lost in culture, different fibroblast subpopulations retain distinct functionality in terms of Wnt signalling, T cell communication and the ability to support human epidermal reconstitution in organotypic culture. Furthermore, while some fibroblast subpopulations are spatially segregated, others are not. These findings have profound implications for normal wound healing and diseases characterized by excessive fibrosis, and suggest that ex vivo expansion or in vivo ablation of specific fibroblast subpopulations may have therapeutic applications. Overall design: Spatial RNA sequencing of human papillary versus reticular dermis for 3 individuals, and single cell RNA sequencing of dermal fibroblasts for a single individual.
Spatial and Single-Cell Transcriptional Profiling Identifies Functionally Distinct Human Dermal Fibroblast Subpopulations.
Specimen part, Subject
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