Cockayne syndrome (CS) is an inherited neurodevelopmental disorder with progeroid features. Although the genes responsible for CS have been implicated in a variety of DNA repair- and transcription-related pathways, the nature of the molecular defect in CS remains mysterious. We sought to define this defect by expression analysis of cells lacking functional CSB, a SWI/SNF-like ATPase that is responsible for most CS cases.
Cockayne syndrome group B protein (CSB) plays a general role in chromatin maintenance and remodeling.
Before and after anaerobic Fe(II) shocked WT and ?bqsR of late stationary phase P. aeruginosa PA14 strains Associated publication: Kreamer NN, Costa F, Newman DK. 2015. The ferrous iron-responsive BqsRS two-component system activates genes that promote cationic stress tolerance. mBio 6(1):e02549-14. doi:10.1128/mBio.02549-14. Overall design: Expression profiles of rRNA-depleted total RNA from WT and ?bqsR Fe(II)-shocked (before and after 30 min incubation with 200 µM ferrous ammonium sulfate ) cultures grown anaerobically to deep stationary phase (A500 = 0.8) in Fe-limited (1 µM ferrous ammonium sulfate) MOPS minimal medium containing succinate as the carbon source, in triplicate
The ferrous iron-responsive BqsRS two-component system activates genes that promote cationic stress tolerance.
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The specialized corneal epithelium requires differentiated properties, specific for its role at the anterior surface of the eye, thus tight maintenance of the differentiated qualities of the corneal epithelial is essential. Our studies have focused on pinin (PNN), an exon junction component (EJC) that has dramatic implications on corneal epithelial cell differentiation and may act as a stabilizer of the corneal epithelial cell phenotype. Our studies revealed that PNN is involved in both transcriptional repression complexes and the spliceosomal complexes, placing PNN at the fulcrum between chromatin and mRNA splicing. Transcriptome analysis of PNN-knockdown cells revealed clear and reproducible alterations in transcript profiles and splicing patterns of a subset of genes that would significantly impact the epithelial cell phenotype. Here, we further investigate PNNâ€™s role in the regulation of gene expression and alternative splicing (AS) in a corneal epithelial context. We used human corneal epithelial cells (HCET cells) that carry doxycycline-inducible PNN-knockdown shRNA vector and performed RNA-seq to determine differential gene expression and differential AS events. Multiple genes and AS events were identified as differentially expressed between PNN-knockdown and controls cells. Genes up-regulated by PNN-knockdown included a large proportion of genes that are associated with processes associated with enhanced cell migration and ECM remodeling including: MMPs, ADAMs, HAS2, LAMA3, CXCRs and UNC5C. Genes down-regulated in response to PNN depletion included: IGFBP5. FGD3, FGFR2, PAX6, RARG and SOX10. AS events in PNN compared to controls was also more likely to be detected, and uregulated in PNN-knockdowns. In particular, 60% of exon skipping events detected in only one condition were detected in PNN-knockdowns and of the shared exon skipping events, 92% of those differentially expressed were more frequent in the PNN-knockdown. This suggests that in the absence of PNN the epithelial cells are dramatically transformed in the amount and composition of isoforms and that PNN plays a crucial role in the selection of which isoforms differentiating cells produce. Many of the genes affected by PNN-knockdown are known to affect epithelial phenotype. This window into the complexity of RNA splicing in the corneal epithelium implies that PNN exerts broad influence over the regulation and maintenance of epithelial cell phenotype. Overall design: We used HCET cells that carry doxycycline-inducible PNN knockdown shRNA vector and performed RNA-seq to determine differential gene expression and differential alternative splicing events.
RNA-seq analysis of impact of PNN on gene expression and alternative splicing in corneal epithelial cells.
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The polyadenosine RNA binding proteins (Pabs) represent one class of RNA binding proteins that play critical roles in gene expression. This class includes the well-studied nuclear and cytoplasmic Pabs, PABPN1 and PABPC1, respectively, as well as the newly characterized nuclear Pab, zinc finger CCCH-type containing #14, or ZC3H14. ZC3H14 was recently linked to a form of intellectual disability, suggesting a critical role for ZC3H14 in neurons; however, the post-transcriptional function of ZC3H14 is unknown. In this study, we performed a microarray analysis of cells depleted of ZC3H14 or PABPN1 in MCF-7 breast cancer cells. These results revealed that PABPN1 significantly affected ~17% of expressed transcripts as compared to ZC3H14, which affected ~1% of expressed transcripts, suggesting that ZC3H14 has specific mRNA targets. The differentially expressed mRNAs identified in this analysis not only provide information about the classes and types of transcripts that are regulated by these proteins, but also represent a set of transcripts that could be directly bound by ZC3H14 and/or PABPN1.
The Polyadenosine RNA-binding Protein, Zinc Finger Cys3His Protein 14 (ZC3H14), Regulates the Pre-mRNA Processing of a Key ATP Synthase Subunit mRNA.
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We report that increased nutrient availability increases breeding success and egg production. RNA-seq analysis revealed that parental diet altered the expression of metabolic genes in the unfertilized eggs. Offspring from the differentially fed parents showed altered survival and energy expenditure as adults. Overall design: RNA from unfertilized eggs after two parental diets.
Dietary Intake Influences Adult Fertility and Offspring Fitness in Zebrafish.
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Hox genes are critical developmental transcription factor. We found that in mice with disrupted expression of Hoxa6, Hoxb6 and Hoxc6 there is significantly disrupted endocrine pancreas development. We used microarray analysis to probe for possible molecular mechanisms involed in Hox6 signaling in pancreas development.
Mesenchymal Hox6 function is required for mouse pancreatic endocrine cell differentiation.
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Cockayne syndrome is a segmental progeria most often caused by mutations in the CSB gene encoding a SWI/SNF-like ATPase required for transcription-coupled DNA repair (TCR). Over 43 Mya before marmosets diverged from humans, a piggyBac3 (PGBD3) transposable element integrated into intron 5 of the CSB gene. As a result, primate CSB genes now generate both CSB protein and a conserved CSB-PGBD3 fusion protein in which the first 5 exons of CSB are alternatively spliced to the PGBD3 transposase. We show by microarray analysis that expression of the fusion protein alone in CSB-null UV-sensitive syndrome cells (UVSS1KO) cells induces an interferon-like response that resembles both the innate antiviral response and the prolonged interferon response normally maintained by unphosphorylated STAT1 (U-STAT1); moreover, as might be expected based on conservation of the fusion protein, this potentially cytotoxic interferon-like response is largely reversed by coexpression of functional CSB protein. Interestingly, expression of CSB and the CSB-PGBD3 fusion protein together, but neither alone, upregulates the insulin growth factor binding protein IGFBP5 and downregulates IGFBP7, suggesting that the fusion protein may also confer a metabolic advantage, perhaps in the presence of DNA damage. Finally, we show that the fusion protein binds in vitro to members of a dispersed family of 900 internally deleted piggyBac elements known as MER85s, providing a potential mechanism by which the fusion protein could exert widespread effects on gene expression. Our data suggest that the CSB-PGBD3 fusion protein is important in both health and disease, and could play a role in Cockayne syndrome.
The conserved Cockayne syndrome B-piggyBac fusion protein (CSB-PGBD3) affects DNA repair and induces both interferon-like and innate antiviral responses in CSB-null cells.
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Extremely slow growth imposed by energy limitation is a ubiquitous but poorly understood physiological state for microbes. We used oxygen limitation to impose this state on Pseudomonas aeruginosa and measured newly synthesized proteins using a time-selective proteome labeling method (BONCAT) to identify relevant regulators and metabolic pathways. We further characterized one upregulated protein that has no homology to any known protein domains. This small, acidic protein is post-transcriptionally regulated and physically interacts with RNA polymerase, binding near the secondary channel during transcription elongation, and leading to widespread effects on gene expression. For some genes, the impacts on transcript and protein levels are different, suggesting possible modulation of translation as well. These effects have phenotypic consequences, as deletion of the gene affects biofilm formation, secondary metabolite production, and fitness in fluctuating conditions. Based on these phenotypes, we have designated the protein SutA (survival under transitions). Overall design: Profiles of rRNA-depleted total RNA from WT, ?sutA (PA14_69770), and SutA-overexpressing cells grown late exponential phase in minimal medium containing pyruate as the carbon source, in triplicate
SutA is a bacterial transcription factor expressed during slow growth in Pseudomonas aeruginosa.
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The circadian clock orchestrates rhythms in physiology and behavior, allowing the organism to adapt to daily environmental changes. Recently, efforts have been made to unravel the connection between the circadian clock and metabolism and to understand how the peripheral clock in different organs coordinates circadian responses to maintain metabolic homeostasis. It is becoming clear that diet can influence diurnal rhythms, however, the molecular mechanisms responsible for alterations in daily oscillations and how tissue-specific clocks interpret a nutritional challenge are not well understood. Here, we reveal tissue-specific circadian plasticity in response to a ketogenic diet (KD) in both the liver and intestine and a remarkable deviation within these two tissues following subsequent carbohydrate supplementation. KD caused a dramatic change in the circadian transcriptome in both liver and intestine in a tissue-specific fashion. In particular, both the amplitude of clock genes as well as specific BMAL1 recruitment was profoundly altered by KD while the intestinal clock was devoid of such plasticity. While PPARG nuclear accumulation was circadian in both tissues, it showed substantial phase specificity as did downstream targets. Finally, the gut and liver clocks had distinct responses to carbohydrate supplementation to KD composition, suggesting a higher plasticity in the ileum whose gene expression was almost restored to control baseline. For the first time our results demonstrate how nutrients modulate clock function in a tissue-specific manner, suggesting that a food stress arouses unique circadian molecular signatures in distinct peripheral tissues.
Distinct Circadian Signatures in Liver and Gut Clocks Revealed by Ketogenic Diet.
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