The permanent reduction of TIA proteins molds expression transcriptome in HeLa cells.

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.

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Núñez M, Sánchez-Jiménez C, Alcalde J, Izquierdo JM