Previous lineage analyses have shown that retinal progenitor cells (RPCs) are multipotent throughout development, and expression profiling studies have shown a great deal of molecular heterogeneity among RPCs. To determine if the molecular heterogeneity predicts that an RPC will produce particular types of progeny, clonal lineage analysis was used to investigate the progeny of a subset of RPCs, those that express the basic helix-loop-helix (bHLH) transcription factor, Olig2. In contrast to the large and complex set of clones generated by viral marking of random embryonic RPCs, the embryonic Olig2+ RPCs underwent terminal divisions, producing small clones with primarily two of the five cell types being made by the pool of RPCs at that time. The embryonically produced cell types made by Olig2+ RPCs were cone photoreceptors and horizontal cell (HC) interneurons. Moreover, the embryonic Olig2+ RPC did not make the later Olig2+ RPC. The later, postnatal Olig2+ RPCs also made terminal divisions, which were biased towards production of rod photoreceptors and amacrine cell (AC) interneurons. These data indicate that the multipotent progenitor pool is made up of distinctive types of RPCs, which have biases towards producing subsets of retinal neurons in a terminal division, with the types of neurons produced varying over time. This strategy is similar to that of the developing Drosophila melanogaster ventral nerve cord, with the Olig2+ cells behaving as ganglion mother cells.
Transcription factor Olig2 defines subpopulations of retinal progenitor cells biased toward specific cell fates.
Specimen part
View SamplesHigh-throughput systems for gene expression profiling have been developed and matured rapidly through the past decade. Broadly, these can be divided into two categories: hybridization-based and sequencing-based approaches. With data from different technologies being accumulated, concerns and challenges are raised regarding data comparability and agreement across technologies. Within an ongoing large-scale cross-platform data comparison framework, we report here a comparison based on identical samples between one-dye DNA microarray platforms and MPSS (Massively Parallel Signature Sequencing). The DNA microarray platforms generally provided highly correlated data, while moderate correlations between microarrays and MPSS were obtained. Disagreements between the two types of technologies can be attributed to limitations inherent to both technologies. The variation found between pooled biological replicates underlines the importance of exercising caution in identification of differential expression, especially for the purposes of biomarker discovery. Based on different principles, hybridization-based and sequencing-based technologies should be considered complementary to each other, rather than competitive, and currently, both provide indispensable tools for transcriptome profiling.
Comparison of hybridization-based and sequencing-based gene expression technologies on biological replicates.
No sample metadata fields
View SamplesWe wanted to understand at what level BTS acts, i.e. how upstream BTS acts and if BTS misregulation affets only a subset or multiple subsets of Fe regulated genes. We studied WT and bts-3 mutant roots.
BRUTUS and its paralogs, BTS LIKE1 and BTS LIKE2, encode important negative regulators of the iron deficiency response in Arabidopsis thaliana.
Specimen part
View SamplesGene expression microarrays have made a profound impact in biomedical research. The diversity of platforms and analytical methods has made comparison of data from multiple platforms very challenging. In this study, we describe a framework for comparisons across platforms and laboratories. We have attempted to include nearly all the available commercial and in house platforms. Using probe sequences matched at the exon level improved consistency of measurements across the different microarray platforms compared to annotation-based matches. Generally, consistency was good for highly expressed genes, and variable for genes with lower expression values as confirmed by QRT-PCR. Concordance of measurements was higher between laboratories on the same platform than across platforms. We demonstrate that, after stringent pre-processing, commercial arrays were more consistent than in-house arrays, and by most measures, one-dye platforms were more consistent than two-dye platforms.
A sequence-oriented comparison of gene expression measurements across different hybridization-based technologies.
No sample metadata fields
View SamplesGene expression microarrays have made a profound impact in biomedical research. The diversity of platforms and analytical methods has made comparison of data from multiple platforms very challenging. In this study, we describe a framework for comparisons across platforms and laboratories. We have attempted to include nearly all the available commercial and in-house platforms. Using probe sequences matched at the exon level improved consistency of measurements across the different microarray platforms compared to annotation-based matches. Generally, consistency was good for highly expressed genes, and variable for genes with lower expression values as confirmed by QRT-PCR. Concordance of measurements was higher between laboratories on the same platform than across platforms. We demonstrate that, after stringent pre-processing, commercial arrays were more consistent than in-house arrays, and by most measures, one-dye platforms were more consistent than two-dye platforms.
A sequence-oriented comparison of gene expression measurements across different hybridization-based technologies.
No sample metadata fields
View SamplesInfection of Kaposi's sarcoma associated herpes virus (KSHV) has been linked to the development of primary effusion lymphoma (PEL), which is characterized by the loss of expression of B cell markers and effusions in the body cavities. This unique clinical feature of PEL has been attributed to their distinctive gene expression profile which shows overexpression of genes in various signaling pathways. KSHV-encoded latent protein vFLIP K13 has been shown to promote the survival and proliferation of PEL cells. In this study, we have employed gene array analysis followed by bioinformatics analysis of coordinated transcriptional factors network as well as biological pathways to characterize the effect of K13 on PEL-derived BCBL1 cells. We observed that genes associated with Cytokine signaling, Cell death, NF-kappaB and Cell adhesion pathways were differentially regulated by K13.
A computational profiling of changes in gene expression and transcription factors induced by vFLIP K13 in primary effusion lymphoma.
Specimen part, Cell line, Treatment
View SamplesIntegrated microarray and multiplex cytokine analyses of Kaposi's Sarcoma Asssociated Herpesvirus viral FLICE Inhibitory Protein K13 affected genes and cytokines in human blood vascular endothelial cells. The KSHV-encoded K13 protein is one of the few proteins to be expressed in latently-infected spindle cells and the ectopic expression of K13 in human vascular endothelial cells is sufficient to transform them into spindle cells.
Integrated microarray and multiplex cytokine analyses of Kaposi's Sarcoma Associated Herpesvirus viral FLICE Inhibitory Protein K13 affected genes and cytokines in human blood vascular endothelial cells.
Specimen part
View SamplesOsteoarthritis is characterized by degeneration of cartilage and bone in the synovial joints. Recent findings suggest that inflammation may play a role in osteoarthritis, with synovitis being associated with the clinical symptoms of osteoarthritis. Furthermore, we have found that levels of inflammatory complement components are abnormally high in the synovial fluid of individuals with osteoarthritis.
Identification of a central role for complement in osteoarthritis.
Sex, Age, Specimen part
View SamplesWe report here that KSHV viral infection targets the NF-kB pathway which is crucial for cell survival. KSHV protein vFLIP K13 is known to directly interact with cellular protein NEMO of the NF-kB pathway. We used gene expression array to suggets that the interaction of K13 with NEMO is important to activate NF-kB pathway.
NEMO is essential for Kaposi's sarcoma-associated herpesvirus-encoded vFLIP K13-induced gene expression and protection against death receptor-induced cell death, and its N-terminal 251 residues are sufficient for this process.
Specimen part, Cell line
View SamplesLinker histone H1 is a protein component of chromatin and has been linked to chromatin compaction and global gene silencing.It has been sugegsted that H1 plays a significant role, regulating a relatively small number of genes. Here we show that H1.2- a variant of H1 subtype is recruited to chromatin region and is dependent on EZH2-mediated H3K27me3. Therefore a Gene expression array analysis was carried out with H1.2 as well as EZH2 knockout MCF7 cells to confirm the interlationship of H1.2 and EZH2 activity.
Linker histone H1.2 establishes chromatin compaction and gene silencing through recognition of H3K27me3.
Cell line
View Samples