Purpose: The goals of this study were to determine whether the spliceosome interacts with non-intronic mRNAs Methods: RNAseq was performed on RNA that immunoprecipitated with the yeast SMD1 protein. Tandem-affinity-purified RNAs were extracted and RNAseq libraries were generated using the EpiCentre ScriptSeq kit (v1). We also performed RNAseq experiments on rRNA depleted total RNA extracted from an exosome mutant (rrp6?), a temperature-sensitive splicing mutant (prp40-1) and a parental strain (BY4741). The rRNA was depleted using the Invitrogen RiboMinus kit, according to manufactureres procedures. The depleted RNA was subsequently treated with Turbo DNAse I (Ambion) and RNAseq libraries were generated using the EpiCentre ScriptSeq kit (v1). Results: The SM RNAseq data identified a number of non-intronic mRNAs that appeard to be bound by the spliceosome. Among these was the BDF2 mRNA, which enocdes for a bromo-domain protein. BDF2 was highly enriched in both SM-IP datasets and was therefore analyzed in more detail. To determine if other non-intronic mRNAs could be regulated by the spliceosome, we analysed the transcriptome in the rrp6?, the prp40-1 and a parental strain. Bioinformatic analysis of these data sets revealed that roughly 1% of the non-intronic mRNAs in yeast could be targeted by the spliceosome. TopHat revealed cannonical splice junctions in roughly 30 non-intronic mRNAs, indicating that these messages are spliced. Conclusions: We demonstrate, for the first time, that the spliceosome can regulate expression of non-intronic mRNAs via one and/or two RNA cleavage events. We refer to this process as Spliceosome Mediated Decay (SMD). Overall design: We report RNAseq data for two SM immunoprecipitation experiments and RNAseq datasets for the parental strain (BY4741), the prp40-1 mutant, and the rrp6? strain.
Spliceosome-mediated decay (SMD) regulates expression of nonintronic genes in budding yeast.
Subject
View SamplesAn unbalanced karyotype, a condition known as aneuploidy, has a profound impact on cellular physiology and is a hallmark of cancer. Determining how aneuploidy affects cells is thus critical to understanding tumorigenesis. Here we show that aneuploidy interferes with the degradation of autophagosomes within lysosomes. Mis-folded proteins that accumulate in aneuploid cells due to aneuploidy-induced proteomic changes overwhelm the lysosome with cargo, leading to the observed lysosomal degradation defects. Importantly, aneuploid cells respond to lysosomal saturation. They activate a lysosomal stress pathway that specifically increases the expression of genes needed for autophagy-mediated protein degradation. Our results reveal lysosomal saturation as a universal feature of the aneuploid state that must be overcome during tumorigenesis. Overall design: RPE-1 cells either untreated or treated with one of Reversine, Bafilomycin A1 or MG132, each condition was done in triplicate. D14-*_Control: untreated control D14-*_Rev: cells treated with 0.5uM Reversine for 24hrs and harvested 48hrs later D14-*_Baf: cells treated with 0.1uM BafA1 for 6hrs D14-*_Mg: cells treated with 1uM MG132 for 24 hrs
Aneuploidy-induced cellular stresses limit autophagic degradation.
No sample metadata fields
View SamplesCell adhesion in plants is mediated predominantly by pectins, a group of complex cell wall associated polysaccharides. An Arabidopsis mutant, friable1 (frb1), was identified through a screen of T-DNA insertion lines that exhibited defective cell adhesion. Interestingly, the frb1 plants displayed both cell and organ dissociations and also ectopic organ fusions. The FRB1 gene encodes a Golgi-localized, plant specific protein with only weak sequence similarities to known proteins (DUF246). Unlike other cell adhesion deficient mutants, frb1 mutants do not have reduced levels of adhesion related cell wall polymers, such as pectins. Instead, FRB1 affects the abundance of galactose- and arabinose-containing oligosaccharides in the Golgi. Furthermore, frb1 mutants displayed alteration in pectin methylesterification, cell wall associated extensins and xyloglucan microstructure. We propose that abnormal FRB1 action has pleiotropic consequences on wall architecture, affecting both the extensin and pectin matrices, with consequent changes to the biomechanical properties of the wall and middle lamella, thereby influencing cell-cell adhesion.
The FRIABLE1 gene product affects cell adhesion in Arabidopsis.
Specimen part
View SamplesAbnormal activities of histone lysine demethylases (KDMs) and lysine deacetylases (HDACs) are associated with aberrant gene expression in breast cancer development. However, the precise molecular mechanisms underlying the crosstalk between KDMs and HDACs in chromatin remodeling and regulation of gene transcription are still elusive. In this study, we showed that treatment of human breast cancer cells with inhibitors targeting the zinc cofactor dependent class I/II HDACs, but not NAD+ dependent class III HDACs, led to significant increase of H3K4me2 which is a specific substrate of histone lysine-specific demethylase 1 (LSD1) and a key chromatin mark promoting transcriptional activation. We also demonstrated that inhibition of LSD1 activity by a pharmacological inhibitor, pargyline, or siRNA resulted in increased acetylation of H3K9 (AcH3K9). However, siRNA knockdown of LSD2, a homolog of LSD1, failed to alter the level of AcH3K9, suggesting that LSD2 activity may not be functionally connected with HDAC activity. Combined treatment with LSD1 and HDAC inhibitors resulted in enhanced levels of H3K4me2 and AcH3K9, and exhibited synergistic growth inhibition of breast cancer cells. Finally, microarray screening identified a unique subset of genes whose expression was significantly changed by combination treatment with inhibitors of LSD1 and HDAC. Our study suggests that LSD1 intimately interacts with histone deacetylases in human breast cancer cells. Inhibition of histone demethylation and deacetylation exhibits cooperation and synergy in regulating gene expression and growth inhibition, and may represent a promising and novel approach for epigenetic therapy of breast cancer.
Inhibitors of histone demethylation and histone deacetylation cooperate in regulating gene expression and inhibiting growth in human breast cancer cells.
Specimen part, Cell line
View SamplesProtein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3'' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks. Overall design: We generated protein occupancy cDNA libraries for two biological replicates. Briefly, we crosslinked 4SU-labeled cells and purified protein-mRNA complexes using oligo(dT)-beads. The precipitate was treated with RNAse I to reduce the protein-crosslinked RNA fragments to a length of about 30-60 nt. To remove non-crosslinked RNA, protein-RNA complexes were precipitated with ammonium sulfate and blotted onto nitrocellulose. The RNA was recovered by Proteinase K treatment, ligated to cloning adapters, and reverse transcribed. The resulting cDNA libraries were PCR-amplified and next-generation sequenced
The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts.
Treatment, Subject
View SamplesProtein-RNA interactions are fundamental to core biological processes, such as mRNA splicing, localization, degradation and translation. We developed a photoreactive nucleotide-enhanced UV crosslinking and oligo(dT) purification approach to identify the mRNA-bound proteome using quantitative proteomics and to display the protein occupancy on mRNA transcripts by next-generation sequencing. Application to a human embryonic kidney cell line identified close to 800 proteins. Close to one third of these proteins, were neither previously annotated nor could be functionally predicted to bind RNA. Protein occupancy profiling provides a transcriptome-wide catalog of potential cis-regulatory regions on mammalian mRNAs and showed that large stretches in 3'' UTRs can be contacted by the mRNA-bound proteome, with numerous putative binding sites in regions harboring disease-associated nucleotide polymorphisms. Our observations indicate the presence of a large number of unexpected mRNA-binders with novel molecular functions participating in combinatorial post-transcriptional gene-expression networks. Overall design: To obtain a more detailed picture of the RNA present in the pooled precipitates of four consecutive oligo(dT)-purifications, we constructed a cDNA library by random priming of 4-thiouridine (4SU)- and 6-thioguanosine (6SG)-labeled RNA derived from UV-irradiated (365 nm)and non-irradiated cells. Digital gene expression analysis of the cDNA library of non-irradiated cells, labeled with 4SU and 6SG, was performed. To monitor the incorporation of photoreactive nucleotides into mRNA, we isolated 4SU- and 6SG-labeled RNA from the oligo(dT) precipitate of non-crosslinked cells by biotinylation and streptavidin purification (Dolken et al., 2008).
The mRNA-bound proteome and its global occupancy profile on protein-coding transcripts.
Treatment, Subject
View SamplesWe performed gene expression microarray to examine the potential effect that depletion of HDAC5 (an important HDAC isozyme) or LSD1 (an FAD-dependent histone lysine demethylase) has on the triple-negative breast cancer transcriptome.
HDAC5-LSD1 axis regulates antineoplastic effect of natural HDAC inhibitor sulforaphane in human breast cancer cells.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
ChIP-seq reveals cell type-specific binding patterns of BMP-specific Smads and a novel binding motif.
Specimen part, Cell line, Treatment
View SamplesSmad1/5 are transcription factors that engage in BMP-induced transcription. We determined and analyzed Smad1/5 binding sites by ChIP-sequencing.
ChIP-seq reveals cell type-specific binding patterns of BMP-specific Smads and a novel binding motif.
Specimen part, Treatment
View SamplesSmad1/5 are transcription factors that engage in BMP-induced transcription. We determined and analyzed Smad1/5 binding sites by ChIP-sequencing. We used expression microarrays to compare the Smad1/5 binding sites identified by ChIP-seq to BMP-induced gene expressions.
ChIP-seq reveals cell type-specific binding patterns of BMP-specific Smads and a novel binding motif.
Specimen part, Treatment
View Samples