The ARV1-encoded protein mediates sterol transport from the endoplasmic reticulum (ER) to the plasma membrane. Yeast ARV1 mutants accumulate multiple lipids in the ER and are sensitive to pharmacological modulators of both sterol and sphingolipid metabolism. Using fluorescent and electron microscopy, we demonstrate sterol accumulation, subcellular membrane expansion, elevated lipid droplet formation and vacuolar fragmentation in ARV1 mutants. Motif-based regression analysis of ARV1 deletion transcription profiles indicates activation of Hac1p, an integral component of the UPR. Accordingly, we show constitutive splicing of HAC1 transcripts, induction of a UPR reporter and elevated expression of UPR targets in ARV1 mutants. IRE1, encoding the unfolded protein sensor in the ER lumen, exhibits a lethal genetic interaction with ARV1, indicating a viability requirement for the UPR in cells lacking ARV1. Surprisingly, ARV1 mutants expressing a variant of Ire1p defective in sensing unfolded proteins are viable. Moreover these strains also exhibit constitutive HAC1 splicing that interacts with DTT-mediated perturbation of protein folding. These data suggest a component of UPR induction in arv1? strains is distinct from protein misfolding. Decreased ARV1 expression in murine macrophages also results in UPR induction, particularly up-regulation of activating transcription factor-4, C/EBP homologous protein (CHOP) and apoptosis. Cholesterol loading or inhibition of cholesterol esterification further elevated CHOP expression in ARV1 knockdown cells. Thus, loss or down-regulation of ARV1 disturbs membrane and lipid homeostasis resulting in a disruption of ER integrity, one consequence of which is induction of the UPR.
Loss of subcellular lipid transport due to ARV1 deficiency disrupts organelle homeostasis and activates the unfolded protein response.
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View SamplesNext Generation RNA Sequencing was carried out on human paired left and right atrial appendages from patients with and without Atrial Fibrillation. EdgeR software was used to show a total of 247 genes were found to have significant differential expression between left and right atria. Overall design: Left and Right atrial appendages from 5 patients in Sinus Rhythm and 5 patients in atrial fibrillation were subjected to RNA sequencing and differential gene expression using EdgeR.
Differentially expressed genes for atrial fibrillation identified by RNA sequencing from paired human left and right atrial appendages.
Sex, Specimen part, Subject
View SamplesExposure to ultraviolet (UV) irradiation is the major cause of nonmelanoma skin cancer, the most common form of cancer in the United States. UV irradiation has a variety of effects on the skin associated with carcinogenesis, including DNA damage and effects on signal transduction. The alterations in signaling caused by UV regulate inflammation, cell proliferation, and apoptosis. UV also activates the orphan receptor tyrosine kinase and proto-oncogene Erbb2 (HER2/neu). In this study, we demonstrate that the UV-induced activation of Erbb2 regulates the response of the skin to UV. Inhibition or knockdown of Erbb2 before UV irradiation suppressed cell proliferation, cell survival, and inflammation after UV. In addition, Erbb2 was necessary for the UV-induced expression of numerous proinflammatory genes that are regulated by the transcription factors nuclear factor-kappaB and Comp1, including interleukin-1beta, prostaglandin-endoperoxidase synthase 2 (Cyclooxygenase-2), and multiple chemokines. These results reveal the influence of Erbb2 on the UV response and suggest a role for Erbb2 in UV-induced pathologies such as skin cancer.
Erbb2 regulates inflammation and proliferation in the skin after ultraviolet irradiation.
No sample metadata fields
View SamplesExpression profile of 30 LMP tumours and 60 Serous tumours were compared to identify the biolgical pathways specific to these groups. Genotyping was done to identify the mutations potentially causing these phenotypes
Mutation of ERBB2 provides a novel alternative mechanism for the ubiquitous activation of RAS-MAPK in ovarian serous low malignant potential tumors.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Novel molecular subtypes of serous and endometrioid ovarian cancer linked to clinical outcome.
No sample metadata fields
View SamplesWe used microarrays to profile the expression levels of 285 ovarian samples in order to identify molecular subtypes of the tumour
Novel molecular subtypes of serous and endometrioid ovarian cancer linked to clinical outcome.
No sample metadata fields
View SamplesWe used microarrays to profile the expression levels of 5 tumour samples
Novel molecular subtypes of serous and endometrioid ovarian cancer linked to clinical outcome.
No sample metadata fields
View SamplesMammalian genomes encode several hundred Krüppel-associated box zinc finger proteins (KRAB-ZFPs) that bind DNA in a sequence-specific manner through tandem arrays of C2H2-type zinc fingers and repress transcription via KRAB-dependent recruitment of the silencing cofactor KAP1. The KRAB-ZFP family rapidly amplified and diversified in mammals by segmental gene duplications, mutations, and zinc finger rearrangements likely in response to continued transposable element invasions, but the biological functions and in vivo requirement of these proteins has gone largely unexplored. We determined the genomic binding sites of 61 murine KRAB-ZFPs and genetically deleted five large KRAB-ZFP gene clusters encoding more than 100 of the approximately 360 mouse KRAB-ZFPs. We demonstrate that most KRAB-ZFPs bind to specific retrotransposon families and that many of these retrotransposons are transcriptionally activated in KRAB-ZFP cluster KO ESCs, licensing retrotransposon-derived enhancers to activate nearby genes. Overall design: RNA-seq analysis of KRAB-ZFP cluster KO ES cells and tissues.
KRAB-zinc finger protein gene expansion in response to active retrotransposons in the murine lineage.
Age, Specimen part, Cell line, Subject
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 SamplesThe LEF/TCF family of transcription factors are downstream effectors of the WNT signaling pathway, which drives colon tumorigenesis. LEF/TCFs have a DNA sequence-specific HMG box that binds Wnt Response Elements (WREs). The E tail isoforms of TCFs are alternatively spliced to include a second DNA binding domain called the C-clamp. We show that induction of a dominant negative C-clamp version of TCF1 (dnTCF1E) induces a p21-dependent stall in the growth of DLD1 colon cancer cells. Induction of a C-clamp mutant did not induce p21 or stall cell growth. Microarray analysis revealed that induction of p21 by dnTCF1EWT correlated with a decrease in expression of p21 suppressors that act at multiple levels from transcription (SP5, YAP1, RUNX1), to RNA stability (MSI2), and protein stability (CUL4A). We show that the C-clamp is a sequence specific DNA binding domain that can make contacts with 5-RCCG-3 elements upstream or downstream of WREs. The C-clamp-RCCG interaction was critical for TCF1E mediated transcriptional control of p21-connected target gene promoters. Our results indicate that a WNT/p21 circuit is driven by C-clamp target gene selection.
A WNT/p21 circuit directed by the C-clamp, a sequence-specific DNA binding domain in TCFs.
Specimen part
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