Project description:The reduction of T-cell intracellular antigen (TIA) proteins in transformed cells leads to the acquisition of aberrant cellular phenotypes promoting uncontrolled cell proliferation and tumor growth. Here we show that global and specific translational rates are regulatory gene events that contribute markedly to the acquisition of above cellular phenotypes. For example, we observe a significant increase of ribosomal population and translational machinery components in TIA-reduced HeLa cells. Polysomal microarray analysis shows specific changes at both the transcript and translational level following TIA reduction, identifying translationally regulated mRNAs that are not transcriptionally regulated which seem to be prevalent for the adaptation to the new environmental conditions. Validation of microarray data using RT-QPCR and immunological analysis for representative genes were carried out. Up-regulated in this class of mRNA are those involved in cell-cycle progression and DNA replication/repair, including several mRNAs with specific sequences to bind TIA proteins. Our data support a hypothesis that a concerted activation of both global and selective translational rates is relevant for the transition from quiescent to proliferative status in TIA-depleted HeLa cells.
Project description:Background: Our recent studies strongly suggest that remodeling in the control of gene expression contributes to the progression of cell phenotypes associated to the transient and permanent knock-down of T-cell intracellular antigen 1(TIA1) and TIA1 related/like (TIAR/TIAL1) proteins. In particular, our studies have been focused on transcriptomic profiling of TIA-depleted HeLa cells using transient RNA interference (siRNA-mediated) and genome-wide microarray approaches Results: This study provides, for the first time, TIA1 and TIAR linked-transcriptomic analysis by using RNA-Seq next generation sequencing technology. Illumina RNA-Seq was used to survey transcriptome profiles from permanent TIA1 and TIAR-(shRNA-mediated) deficient HeLa cells. Analysis of the transcriptomes with the Cufflinks tool revealed that differentially expressed genes, isoforms produced by alternative splicing and/or promoter usage as well as microRNAs generated a great transcriptomic heterogeneity which might reflect the complexity linked to these cell phenoypes. The data of differential expression were validated by using genome-wide microarrays and QPCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes term enrichment analysis revealed over-representation of genes associated with cell differentiation, multicellular organismal development, signal transduction, axon guidance and cell adhesion and under-representation of genes associated with positive regulation of migration, cell adhesion, response to organic substance, prostaglandin metabolic process and blood coagulation. Conclusions: Taken together, our observations point out towards an inhibitory role of TIA proteins in cell proliferation and growth, there appears to be an apparent molecular discrepancy regarding the effects of TIA proteins based on whether the proteins are depleted transiently (siRNA-mediated) or permanently (shRNA-mediated), suggesting the existence of clonal selection mechanisms of cellular populations in permanently TIA1/TIAR-depleted HeLa cells. For each cell type, three biological replicates were prepared and hybridized to Affymetrix GeneChips (HG U133plus2). 3+3 hybridizations in total for a single comparison KO vs WT.
Project description:The reduction of T-cell intracellular antigen (TIA) proteins in transformed cells leads to the acquisition of aberrant cellular phenotypes promoting uncontrolled cell proliferation and tumor growth. Here we show that global and specific translational rates are regulatory gene events that contribute markedly to the acquisition of above cellular phenotypes. For example, we observe a significant increase of ribosomal population and translational machinery components in TIA-reduced HeLa cells. Polysomal microarray analysis shows specific changes at both the transcript and translational level following TIA reduction, identifying translationally regulated mRNAs that are not transcriptionally regulated which seem to be prevalent for the adaptation to the new environmental conditions. Validation of microarray data using RT-QPCR and immunological analysis for representative genes were carried out. Up-regulated in this class of mRNA are those involved in cell-cycle progression and DNA replication/repair, including several mRNAs with specific sequences to bind TIA proteins. Our data support a hypothesis that a concerted activation of both global and selective translational rates is relevant for the transition from quiescent to proliferative status in TIA-depleted HeLa cells. Two independent replicates were performed for each experimental condition and hybridized to SurePrint G3 Human GE 8x60K Agilent microarrays.
Project description:Background: Our recent studies strongly suggest that remodeling in the control of gene expression contributes to the progression of cell phenotypes associated to the transient and permanent knock-down of T-cell intracellular antigen 1(TIA1) and TIA1 related/like (TIAR/TIAL1) proteins. In particular, our studies have been focused on transcriptomic profiling of TIA-depleted HeLa cells using transient RNA interference (siRNA-mediated) and genome-wide microarray approaches Results: This study provides, for the first time, TIA1 and TIAR linked-transcriptomic analysis by using RNA-Seq next generation sequencing technology. Illumina RNA-Seq was used to survey transcriptome profiles from permanent TIA1 and TIAR-(shRNA-mediated) deficient HeLa cells. Analysis of the transcriptomes with the Cufflinks tool revealed that differentially expressed genes, isoforms produced by alternative splicing and/or promoter usage as well as microRNAs generated a great transcriptomic heterogeneity which might reflect the complexity linked to these cell phenoypes. The data of differential expression were validated by using genome-wide microarrays and QPCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes term enrichment analysis revealed over-representation of genes associated with cell differentiation, multicellular organismal development, signal transduction, axon guidance and cell adhesion and under-representation of genes associated with positive regulation of migration, cell adhesion, response to organic substance, prostaglandin metabolic process and blood coagulation. Conclusions: Taken together, our observations point out towards an inhibitory role of TIA proteins in cell proliferation and growth, there appears to be an apparent molecular discrepancy regarding the effects of TIA proteins based on whether the proteins are depleted transiently (siRNA-mediated) or permanently (shRNA-mediated), suggesting the existence of clonal selection mechanisms of cellular populations in permanently TIA1/TIAR-depleted HeLa cells.
Project description:Background: T-cell intracellular antigen (TIA) proteins function as regulators of cell homeostasis. These proteins control gene expression globally at multiple levels in response to dynamic regulatory changes and environmental stresses. Herein we identified a micro(mi)RNA signature associated to transiently TIA-depleted HeLa cells and analyzed the potential role of miRNAs combining genome-wide analysis data on mRNA and miRNA profiles. Results: Using high-throughput miRNA expression profiling, transient depletion of TIA-proteins in HeLa cells was observed to promote significant and reproducible changes (>2-fold, FDR<0.0001) affecting to a pool of up-regulated miRNAs (miR-30b*, miR125a-3p, miR-193a-5p, miR-197_MM2, miR-203, miR-210, miR-371-5p, miR-373*, miR-483-5p, miR-492, miR-498, miR-503, miR-572, miR-586, miR-612, miR-615, miR-623, miR-625, miR-629, miR-638, miR-658, miR-663, miR-671, miR-769-3p and miR-744). Differential expression analysis of some miRNAs was validated by reverse transcription and real time PCR. By target prediction and combined analysis of the genome-wide expression profiles of the mRNAs and miRNAs identified in TIA-depleted HeLa cells, we detected concomitant connections between up-regulated miRNAs and putative and experimental targeted mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database analyses suggest that targeted mRNAs are related with biological processes associated to the regulation of DNA-dependent transcription, signal transduction and multicellular organismal development as well as with the enrichment of pathways in cancer, focal adhesion, regulation of actin cytoskeleton and MAPK and Wnt signalling pathways, respectively. Conclusion: All this considered, these observations suggest that specific miRNAs could act as potential mediators of the epigenetic switch linking transcriptomic dynamics and cell phenotypes mediated by TIA proteins.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Background: T-cell intracellular antigen (TIA) proteins function as regulators of cell homeostasis. These proteins control gene expression globally at multiple levels in response to dynamic regulatory changes and environmental stresses. Herein we identified a micro(mi)RNA signature associated to transiently TIA-depleted HeLa cells and analyzed the potential role of miRNAs combining genome-wide analysis data on mRNA and miRNA profiles. Results: Using high-throughput miRNA expression profiling, transient depletion of TIA-proteins in HeLa cells was observed to promote significant and reproducible changes (>2-fold, FDR<0.0001) affecting to a pool of up-regulated miRNAs (miR-30b*, miR125a-3p, miR-193a-5p, miR-197_MM2, miR-203, miR-210, miR-371-5p, miR-373*, miR-483-5p, miR-492, miR-498, miR-503, miR-572, miR-586, miR-612, miR-615, miR-623, miR-625, miR-629, miR-638, miR-658, miR-663, miR-671, miR-769-3p and miR-744). Differential expression analysis of some miRNAs was validated by reverse transcription and real time PCR. By target prediction and combined analysis of the genome-wide expression profiles of the mRNAs and miRNAs identified in TIA-depleted HeLa cells, we detected concomitant connections between up-regulated miRNAs and putative and experimental targeted mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database analyses suggest that targeted mRNAs are related with biological processes associated to the regulation of DNA-dependent transcription, signal transduction and multicellular organismal development as well as with the enrichment of pathways in cancer, focal adhesion, regulation of actin cytoskeleton and MAPK and Wnt signalling pathways, respectively. Conclusion: All this considered, these observations suggest that specific miRNAs could act as potential mediators of the epigenetic switch linking transcriptomic dynamics and cell phenotypes mediated by TIA proteins. The analysis includes two cell types. Three biological replicates were performed per cell type and they were compared by using three dual-channel microarray hybridizations.