Heterosis which is the improved vigor of F1-hybrids compared to their parents is widely exploited in maize (Zea mays L.) breeding to produce elite hybrids of superior yield. The transcriptomes of the maize inbred lines B73 and Mo17 and their reciprocal hybrid offspring were surveyed in the meristematic zone, the elongation zone, cortex and stele tissues of primary roots, prior to the developmental manifestation of heterosis. Single parent expression (SPE) is consistent with the dominance model for heterosis in that it denotes genes that are expressed in only one parent but in both reciprocal hybrids. In primary root tissues, between 1,027 (elongation zone) and 1,206 (stele) SPE patterns were observed. As a consequence, hybrids displayed in each tissue >400 active genes more than either parent. Analysis of tissue-specific SPE dynamics revealed that 1,233 of 2,233 SPE genes displayed SPE in all tissues in which they were expressed while 1,000 SPE genes displayed in at least one tissue a non-SPE pattern. In addition, 64% (17,351/ 27,164) of all expressed genes were assigned to the two subgenomes which are the result of an ancient genome duplication. By contrast, only between 18 and 25% of the SPE genes were assigned to a subgenome suggesting that a disproportionate number of SPE genes are evolutionary young and emerged after genome duplication. We hypothesize that this phenomenon is associated with human selection of favorable maize genotypes which might primarily affect younger genes rather than genes whose functions have been conserved for millions of years.
Nonsyntenic genes drive highly dynamic complementation of gene expression in maize hybrids.
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No sample metadata fields
View SamplesTransposable elements (TEs) comprise a substantial portion of many eukaryotic genomes and are typically transcriptionally silenced. RNA–dependent RNA polymerase 2 (RDR2) is a component of the RNA–directed DNA methylation (RdDM) silencing pathway. In maize, loss of mediator of paramutation1 (mop1) encoded RDR2 function results in reactivation of transcriptionally silenced Mu transposons and a substantial reduction in the accumulation of 24 nt short-interfering RNAs (siRNAs) that recruit RNA silencing components. An RNA–seq experiment conducted on shoot apical meristems (SAMs) revealed that, as expected based on a model in which RDR2 generates 24 nt siRNAs that suppress expression, most differentially expressed DNA TEs (78%) were up-regulated in the mop1 mutant. In contrast, most differentially expressed retrotransposons (68%) were down-regulated. This striking difference suggests that distinct silencing mechanisms are applied to different silencing templates. In addition, 6,000 genes (24% of analyzed genes), including nearly 80% (286/361) of genes in chromatin modification pathways, were differentially expressed. Overall, two-thirds of differentially regulated genes were down-regulated in the mop1 mutant. This finding suggests that RDR2 plays a significant role in regulating the expression of not only transposons, but also of genes. A re-analysis of existing small RNA data identified both RDR2–sensitive and RDR2–resistant species of 24 nt siRNAs that we hypothesize may at least partially explain the complex changes in the expression of genes and transposons observed in the mop1 mutant. Overall design: Single sequencing library was constructed for mop1 mutant and non-mutant. Each library was sequenced using 2 lanes on a Solexa flow cell. Processed data file 'ZmB73_4a.53_filtered_genes.fasta' and its README file are linked below as supplementary files. The fasta file contains the gene model ID and corresponding sequence generated from maize genome project. This fasta file was used for the following samples: GSM418173, GSM418174, GSM420173, GSM420174, GSM422828, GSM422829.
Loss of RNA-dependent RNA polymerase 2 (RDR2) function causes widespread and unexpected changes in the expression of transposons, genes, and 24-nt small RNAs.
Age, Subject
View SamplesTransposons in maize may be involved in the formation of circRNAs and further modulate phenotypic variation. To test our hypothesis, we performed circRNA-Seq(RNase R treated) on B73 seedlings(third leaves of V3 stage), and uncovered 1,572 high-confidence maize circRNAs, which show distinct genomic features compared to linear transcripts. Comprehensive analyses showed that LINE1-like elements (LLE) and their reverse complementary pairs (RCPLLEs) are significantly enriched in the flanking regions of circRNAs.
Circular RNAs mediated by transposons are associated with transcriptomic and phenotypic variation in maize.
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Specimen part, Disease
View SamplesAn atlas of RNA and protein expression maps across a diverse set of developmental tissues from Zea mays Overall design: RNA-seq collected from a variety of maize tissues
Integration of omic networks in a developmental atlas of maize.
Specimen part, Subject
View SamplesComparison of global transcription profiles in salivary glands from wild-type and JIL-1 null mutant larvae revealed that the expression levels of 1539 genes changed at least two-fold in the mutant and that a substantial number (49%) of these genes were upregulated whereas 51% were downregulated. Overall design: Examination of 2 different transcriptome in 2 genotypes with two replicates.
Genome-wide analysis of regulation of gene expression and H3K9me2 distribution by JIL-1 kinase mediated histone H3S10 phosphorylation in Drosophila.
Specimen part, Subject
View SamplesBulked segregant analysis (BSA) is an efficient method to rapidly and efficiently map genes responsible for mutant phenotypes. This procedure, however, requires access to quantitative genetic markers that are polymorphic in the mapping population. We have developed a modification of BSA (BSR-Seq) that makes use of RNA-Seq reads to efficiently map genes even in populations for which no polymorphic markers have been previously identified. Because of the digital nature of next-generation sequencing (NGS) data, it is possible to conduct de novo SNP discovery and quantitatively genotype BSA samples using the same RNA-Seq data. In addition, analysis of the RNA-Seq data provides information on the effects of the mutant on global patterns of gene expression at no extra cost. In combination these results greatly simplify gene cloning experiments. To demonstrate the utility of this strategy BSR-Seq was used to clone the glossy3 (gl3) gene of maize. Mutants of the glossy loci exhibit altered accumulation of epicuticular waxes on juvenile leaves. We previously generated a large collection of glossy mutants using the Mu transposon system. By subjected a reference allele to BSR-Seq, we were able to map the gl3 locus to a ~2.3Mb interval that is consistent with the results of prior mapping experiments. The single gene located in the 2.3Mb mapping interval that contained a Mu insertion and whose expression was down-regulated in the mutant pool was subsequently demonstrated to be the gl3 gene via the analysis of multiple independently Mu transposon induced mutant alleles. The gl3 gene encodes a putative myb transcription factor, which directly or indirectly affects the expression of a number of genes involved in the biosynthesis of very-long-chain fatty acids.
Changes in genome content generated via segregation of non-allelic homologs.
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No sample metadata fields
View SamplesGene expression profile was analyzed after knockdown of PAEP in lung cancer cell lines 2106T and H1975 as well as in skin cancer cell line MeWo.
Glycodelin: A New Biomarker with Immunomodulatory Functions in Non-Small Cell Lung Cancer.
Specimen part, Cell line, Treatment
View SamplesPurpose:
Sequential gene expression profiling during treatment for identification of predictive markers and novel therapeutic targets in chronic lymphocytic leukemia.
Treatment
View Samplessubstantial number of people at risk to develop type 2 diabetes could not improve insulin sensitivity by physical training intervention. We studied the mechanisms of this impaired exercise response in 20 middle-aged individuals who performed a controlled eight weeks cycling and walking training at 80 % individual VO2max. Participants identified as non-responders in insulin sensitivity (based on Matsuda index) did not differ in pre-intervention parameters compared to high responders. The failure to increase insulin sensitivity after training correlates with impaired up-regulation of mitochondrial fuel oxidation genes in skeletal muscle, and with the suppression of the upstream regulators PGC1 and AMPK2. The muscle transcriptome of the non-responders is further characterized by an activation of TGF and TGF target genes, which is associated with increases in inflammatory and macrophage markers. TGF1 as inhibitor of mitochondrial regulators and insulin signaling is validated in human skeletal muscle cells. Activated TGF1 signaling down-regulates the abundance of PGC1, AMPK2, mitochondrial transcription factor TFAM, and of mitochondrial enzymes. Thus, increased TGF activity in skeletal muscle can attenuate the improvement of mitochondrial fuel oxidation after training and contribute to the failure to increase insulin sensitivity.
TGF-β Contributes to Impaired Exercise Response by Suppression of Mitochondrial Key Regulators in Skeletal Muscle.
Specimen part
View SamplesInvestigation whether hypoxic stabilization of HIF-1alpha quantitatively or qualitatively modifies the gene expression pattern induced by poly I:C, a TLR ligand that does not induce normoxic HIF-1alpha stabilization on its own (non-HIF-1alpha-stabilizing TLR ligand).
Toll-like receptor activation and hypoxia use distinct signaling pathways to stabilize hypoxia-inducible factor 1α (HIF1A) and result in differential HIF1A-dependent gene expression.
No sample metadata fields
View Samples