Human pluripotent stem cells (hPSCs) tend to acquire chromosomal aberrations in culture, which may increase their tumorigenicity. However, the cellular mechanism(s) underlying these aberrations are largely unknown. Here we show that the DNA replication in aneuploid hPSCs is perturbed, resulting in high prevalence of defects in chromosome condensation and segregation. Global gene expression analyses in aneuploid hPSCs revealed decreased levels of actin cytoskeleton genes and their common transcription factor SRF. Down-regulation of SRF or chemical perturbation of actin cytoskeleton organization in diploid hPSCs resulted in increased replication stress and perturbation of chromosome condensation, recapitulating the findings in aneuploid hPSCs. Altogether, our results revealed that in hPSCs DNA replication stress results in a distinctive defect in chromosome condensation, underlying their ongoing chromosomal instability. Our results shed a new light on the mechanisms leading to ongoing chromosomal instability in hPSCs, and may be relevant to tumor development as well.
Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects.
Specimen part, Cell line
View SamplesDiploid and tetraploid budding yeast cell cultures were grown in YPD, at 30C, to O.D. approx. 0.5.
Genome-wide genetic analysis of polyploidy in yeast.
Sex
View SamplesEpsteinBarr virus (EBV) is a common human pathogen that infects over 95% of the population worldwide. In the present study, the whole transcriptome microarray data were generated from peripheral blood mononuclear cells from Chinese children with acute infectious mononucleosis (AIM) and chronic active EBV infection (CAEBV) that were also compared with a publicly available microarray dataset from a study of American college students with AIM. Our study characterized for the first time a broad spectrum of molecular signatures in AIM and CAEBV. The key findings from the transcriptome profiling were validated with qPCR and flow cytometry assays. The most important finding in our study is the discovery of predominant TCR expression and T cell expansion in AIM. This finding, in combination with the striking up-regulation of CD3, CD8 and CD94, suggests that CD8+ T cells and CD94+ NK cells may play a major role in AIM. Moreover, the unique up-regulation of CD64A/B and its significant correlation with the monocyte marker CD14 was observed in CAEBV and that implies an important role of monocytes in CAEBV. In conclusion, our study reveals major cell types (particularly T cells) in the host cellular immune response against AIM and CAEBV.
Whole transcriptome profiling reveals major cell types in the cellular immune response against acute and chronic active Epstein-Barr virus infection.
Sex, Age, Specimen part, Disease
View SamplesBrain perivascular cells have been recently identified as new mesodermal cell type of the human brain.
Perivascular Mesenchymal Stem Cells From the Adult Human Brain Harbor No Instrinsic Neuroectodermal but High Mesodermal Differentiation Potential.
Specimen part
View SamplesMutations in the CLN3 gene lead to juvenile neuronal ceroid lipofuscinosis, a pediatric neurodegenerative disorder characterized by visual loss, epilepsy and psychomotor deterioration. Although most CLN3 patients carry the same 1 kb deletion in the CLN3 gene, their disease phenotype can be variable. The aims of this study were (1) to identify genes that are dysregulated in CLN3 disease regardless of the clinical course that could be useful as biomarkers, and (2) to find modifier genes that affect the progression rate of the disease.
Analysis of potential biomarkers and modifier genes affecting the clinical course of CLN3 disease.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesSmall RNAs (sRNA) that act by base pairing with trans-encoded mRNAs modulate metabolism in response to a variety of environmental stimuli. Here, we describe an Hfq-binding sRNA (FnrS) whose expression is induced upon a shift from aerobic to anaerobic conditions and which acts to down regulate the levels of a variety of mRNAs encoding metabolic enzymes. Anaerobic induction in minimal medium depends strongly on FNR but is also affected by ArcA and CRP. Whole genome expression analysis showed that the levels of at least 32 mRNAs are down regulated upon FnrS overexpression, 15 of which are predicted to base pair with FnrS by TargetRNA. The sRNA is highly conserved across its entire length in numerous enterobacteria, and mutation analysis revealed that two separate regions of FnrS base pair with different sets of target mRNAs. The majority of the target genes previously reported to be down regulated in an FNR-dependent manner lack recognizable FNR binding sites. We thus suggest that FnrS extends the FNR regulon and increases the efficiency of anaerobic metabolism by repressing the synthesis of enzymes that are not needed under these conditions.
Reprogramming of anaerobic metabolism by the FnrS small RNA.
No sample metadata fields
View SamplesBacteria selectively consume some carbon sources over others through a regulatory mechanism termed catabolite repression. Here, we show that the base pairing RNA Spot 42 plays a broad role in catabolite repression in Escherichia coli by directly repressing genes involved in central and secondary metabolism, redox balancing, and the consumption of diverse non-preferred carbon sources. Many of the genes repressed by Spot 42 are transcriptionally activated by the global regulator CRP. Since CRP represses Spot 42, these regulators participate in a specific regulatory circuit called a multi-output feedforward loop. We found that this loop can reduce leaky expression of target genes in the presence of glucose and can maintain repression of target genes under changing nutrient conditions. Our results suggest that base pairing RNAs in feedforward loops can help shape the steady-state levels and dynamics of gene expression.
The base-pairing RNA spot 42 participates in a multioutput feedforward loop to help enact catabolite repression in Escherichia coli.
Specimen part
View SamplesEscherichia coli possesses >65 small proteins of <50 amino acids, many of which are uncharacterized. We have identified a new small protein, MntS, involved in manganese homeostasis. Manganese is a critical micronutrient, serving as an enzyme cofactor and protecting against oxidative stress. Yet manganese is toxic in excess and little is known about its function in cells. Bacteria carefully control intracellular manganese levels using the transcription regulator MntR. Before this work, mntH, which encodes a manganese importer, was the only gene known to respond to manganese via MntR repression in E. coli K12. We demonstrated that mntS is another member of the MntR manganese regulon. We also identified yebN, which encodes a putative manganese efflux pump, as the first gene positively regulated by MntR in Enterobacteria. Since MntS is expressed when manganese levels are low, causes manganese sensitivity when overexpressed, and binds manganese, we propose that MntS may be a manganese chaperone. This study reveals new factors involved in manganese regulation and metabolism and expands our knowledge of how small proteins function.
The Escherichia coli MntR miniregulon includes genes encoding a small protein and an efflux pump required for manganese homeostasis.
Treatment
View SamplesRRF-3 and ERI-1 are first identified proteins required for accumulation of at least some endogenous secondary siRNAs in C.elegans. Genome wide gene expression analysis was performed on L4 stage rrf-3 and eri-1 mutant C. elegans to study effects caused by loss of these proteins. Mutant rrf-3 and eri-1 strains exhibited similar expression patterns when compared to N2 wild type, while 72 transcripts were found to be co-overexpressed and 4 transcripts co-underexpressed (> 2-fold, p< 0.05). Ontology analysis indicated many of the gene products were associated with protein phosphorylation and sperm function. These results provide additional support for the hypothesis that RRF-3 and ERI-1 act together in a siRNA pathway and may indicate biological processes that are related to endo-siRNAs.
Whole genome microarray analysis of C. elegans rrf-3 and eri-1 mutants.
No sample metadata fields
View SamplesARC (NSC 188491, SMA-491), 4-amino-6-hydrazino-7-beta-d-ribofuranosyl-7H-pyrrolo-(2,3-d)-pyrimidine-5-carboxamide, is a nucleoside analog with profound in vitro anti-cancer activity. First identified in a high-throughput screen for inhibitors of p21 mRNA expression, subsequent experiments showed that ARC also repressed expression of hdm2 and survivin, leading to its classification as a global inhibitor of transcription 1. The following Hu U133 plus 2.0 arrays represent single time point (24 hour) gene expression analysis of transcripts altered by ARC treatment. Arrays for the other compounds (sangivamycin and doxorubicin) are included as comparators.
ARC (NSC 188491) has identical activity to Sangivamycin (NSC 65346) including inhibition of both P-TEFb and PKC.
No sample metadata fields
View Samples