Piwi proteins and Piwi-interacting small RNAs (piRNAs) have known functions in transposon silencing in the male germline of fetal and newborn mice. Both are also necessary for spermatogenesis in adult testes, however, their function here remains a mystery. Here, we use germ cell isolations and small RNA sequencing to show that most piRNAs in meiotic spermatocytes originate from clusters in intergenic non-repeat regions of DNA. The regulation of these piRNA clusters, including the processing of the precursor transcripts into individual piRNAs, is accomplished through mostly unknown processes. We present evidence for a regulatory mechanism for one such cluster, named cluster 1082B, located on chromosome 7 in the mouse genome, containing 788 unique piRNAs. The precursor transcript and individual piRNAs within the cluster are repressed by the Alkbh1 dioxygenase and the transcription repressor Tzfp, which are believed to be interaction partners in testis. We observe more than a thousand-fold upregulation of individual piRNAs in pachytene spermatocytes isolated from Alkbh1-/- and TzfpGTi/GTi testes. Repression is further supported by the identification of a 10 bp Tzfp recognition sequence contained within the precursor transcript. Downregulation of long interspersed elements 1 (LINE1) and intracisternal A-particle (IAP) transcripts in the Alkbh1-/- and TzfpGTi/GTi testes leads us to propose a potential role for the 1082B-encoded piRNAs in transposon silencing. Overall design: Characterization of small RNAs in mouse pachytene spermatocytes for wild-type (WT) and Alkbh1-/- and TzfpGTi/GTi, and mRNA in mouse pachytene spermatocytes for wild-type (WT) and Alkbh1-/-
Alkbh1 and Tzfp repress a non-repeat piRNA cluster in pachytene spermatocytes.
Specimen part, Subject
View SamplesBackground: The ability of an organism to repair damages to DNA is inextricably linked to aging and cancer. We have characterized and compared the transcriptome of C. elegans mutants deficient in DNA base excision repair, nucleotide excision repair or both to elucidate the transcriptional changes incurred by the reduction of these repair pathways.
A two-tiered compensatory response to loss of DNA repair modulates aging and stress response pathways.
No sample metadata fields
View SamplesPurpose: The oxidation resistance gene 1 (OXR1) is crucial for protecting against oxidative stress, limiting neurodegeneration and maintaining normal lifespan in eukaryotes. However, the molecular function of OXR1 is still unknown. Previously we showed that human OXR1 regulates expression of antioxidant genes GPX2 and HO-1 via the p21 signaling pathway. To examine the role of hOXR1 in global transcription regulation during cellular stress, we employed RNA sequencing to investigate the transcription profile in hOXR1 depleted HeLa cells. Methods: Control siRNA (siCon) and human OXR1 siRNA (siOXR1) transfected HeLa cells were either harvested directly (siCon_NT, siOXR1_NT) or exposed to 0.5 mM H2O2 for 1 h and then harvested immediately without recovery (siCon_R0h, siOXR1_R0h). Total RNA pooled from duplicate samples was used for RNA sequencing on an Illumina HiSeq2000 platform. The sequence reads that passed quality filters were analyzed at gene level. The Blast2GO program was used to generate gene ontology (GO) annotation of differentially expressed genes (DEGs).The WEGO software was used to further perform GO functional classification and to predict pathways affected. qRT–PCR validation was performed using SYBR Green assays. Results: In total, in non-treated and hydrogen peroxide exposed cells, hOXR1 depletion results in the down-regulation of 554 genes and the up-regulation of 253 genes. These differentially expressed genes include transcription factors (i.e. HIF1A, SP6, E2F8 and TCF3) and numerous genes of the p53 signaling pathway involved in cell-cycle arrest (i.e. cyclin D, CDK6 and p21) and apoptosis (i.e. CytC and CASP9). Western blot analysis reveals that hOXR1 suppresses CASP9 protein expression and reduces post-translational cleavage into its active form. After exposure to hydrogen peroxide (1 h), 56 early response genes were up-regulated in hOXR1 depleted cells, in which 38 of these genes were not induced in control cells. In addition, a subset of the commonly up-regulated early response genes showed a stronger induction in hOXR1 depleted cells (i.e. FOS, JUN and DUSP1). Out of a total of 52 differentially expressed transcription factors in hOXR1 depleted cells under normal physiology and oxidative stress condition, 14 genes (including HIF1A, STAT5A, E2F8 and TCF3) are differentially regulated under H2O2 treatment in hOXR1 silenced cells as compared to control cells. Finally, we demonstrate that hOXR1 depleted cells undergo cell cycle arrest in G2/M phase during oxidative stress. Conclusions: Human OXR1 is important for regulation of the early stress response to oxidative stress in HeLa cells. HOXR1 modulates the p53 signaling pathway via regulation of genes involved in cell cycle arrest, apoptosis and anti-oxidation. Further, hOXR1 regulates numerous transcription factors of importance for cellular stress responses. In summary, hOXR1 may act as a sensor of cellular oxidative stress to regulate the transcriptional networks required to detoxify reactive oxygen species (ROS) and modulate cell cycle arrest and cell death (apoptosis). Overall design: The mRNA profiles of hOXR1 depleted and control Hela cells with or without H2O2 treatment 1 h were generated by RNA sequencing using Illumina Hiseq 2000.
Transcriptome analysis of human OXR1 depleted cells reveals its role in regulating the p53 signaling pathway.
No sample metadata fields
View SamplesOnly rodent embryonic stem (ES) cells can self-renew in the pristine state of pluripotency called the naive or ground state. Human ES (hES) cells self-renew in the so-called primed state of pluripotency, which is an obstacle to research, hindering cost-effective cultivation in media devoid of animal-derived products, genetic stability, and genome engineering. Here we show that forced expression of a hormone-dependent STAT3-ERT2, in combination with LIF and inhibitors of MEK and GSK3beta, allows hES cells to escape from the primed state, and enter a new state designated as TL2i, characterized by the activation of STAT3 target genes, regular passaging by single cell dissociation, and the expression of naive state-specific transcription factors.
Reinforcement of STAT3 activity reprogrammes human embryonic stem cells to naive-like pluripotency.
Specimen part, Cell line
View SamplesTranscriptional profiles of human CD34+ cells cultured in EPO and EST conditions.
Cytokine-mediated increases in fetal hemoglobin are associated with globin gene histone modification and transcription factor reprogramming.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptome instability in colorectal cancer identified by exon microarray analyses: Associations with splicing factor expression levels and patient survival.
Specimen part
View SamplesColorectal cancer is a heterogeneous disease molecularly characterized by inherent genomic instabilities, chromosome instability and microsatellite instability. In the present study we propose transcriptome instability as an analogue to genomic instability on the transcriptome level. Exon microarray data from two independent series of altoghether 160 colorectal cancer tissue samples was used for global alternative splicing detection using the FIRMA algorithm (aroma.affymetrix). The sample-wise amounts of these alternative splicing scores exceeding a defined threshold (deviating exon usage amounts) were summarized to provide the basis for description of transcriptome instability. This characteristic was shown to be associated with splicing factor expression levels and patient survival in both independent sample series.
Transcriptome instability in colorectal cancer identified by exon microarray analyses: Associations with splicing factor expression levels and patient survival.
Specimen part
View SamplesColorectal cancer is a heterogeneous disease molecularly characterized by inherent genomic instabilities, chromosome instability and microsatellite instability. In the present study we propose transcriptome instability as an analogue to genomic instability on the transcriptome level. Exon microarray data from two independent series of altoghether 160 colorectal cancer tissue samples was used for global alternative splicing detection using the FIRMA algorithm (aroma.affymetrix). The sample-wise amounts of these alternative splicing scores exceeding a defined threshold (deviating exon usage amounts) were summarized to provide the basis for description of transcriptome instability. This characteristic was shown to be associated with splicing factor expression levels and patient survival in both independent sample series.
Transcriptome instability in colorectal cancer identified by exon microarray analyses: Associations with splicing factor expression levels and patient survival.
Specimen part
View SamplesWe performed gene expression profiling of P1 and P5 back and tail dermis to uncover potential explanations for the differences in HF formation at different ages and in different body sites.
Inhibition of β-catenin signalling in dermal fibroblasts enhances hair follicle regeneration during wound healing.
Specimen part, Time
View SamplesAging has been shown to be under genetic control in C. elegans. We performed Affymetrix micorarray-based transcriptional profililng of wild type C. elegans strain Bristol N2 during aging to detect temporal changes in gene expression.
A decline in p38 MAPK signaling underlies immunosenescence in Caenorhabditis elegans.
Specimen part
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