Small RNAs (21-24 nt) are pivotal regulators of gene expression that guide both transcriptional and post-transcriptional silencing mechanisms in diverse eukaryotes, including most if not all plants. MicroRNAs (miRNAs) and short interfering RNAs (siRNAs) are the two major types, both of which have a demonstrated and important role in plant development, stress responses and pathogen resistance. In this work, we used a deep sequencing approach (Sequencing-By-Synthesis, or SBS) to develop sequence resources of small RNAs from different maize tissues (including leaves, ears and tassels) collected from wild-type plants of the B73 variety. The high depth of the resulting datasets enabled us to examine in detail critical small RNA features as size distribution, tissue-specific regulation and sequence conservation between different organs in this species. We also developed database resources and a dedicated website (http://smallrna.udel.edu/) with computational tools for allowing other users to identify new miRNAs or siRNAs involved in specific regulatory pathways, verify the degree of conservation of these sequences in other plant species and map small RNAs on genes or larger regions of the maize genome under study. Overall design: Small RNA libraries were derived from leaves, ears and tassels of maize variety B73 (wild-type). Plants were grown in a flood irrigated plot at the University of Arizona (Tucson, AZ, USA) in 2007 and organs were pooled from several plants for each library. Young leaves were collected from 6-weeks-old seedlings. Post-meiotic immature ears were harvested from 10- and 11-week old plants while pre-meiotic tassels were collected from 8-week old plants. Total RNA was isolated using the Plant RNA Purification Reagent (Invitrogen) and submitted to Illumina (Hayward, CA, http://www.illumina.com) for small RNA library construction using approaches described in (Lu et al., 2007) with minor modifications. The small RNA libraries were sequenced with the Sequencing-By-Synthesis (SBS) technology by Illumina. PERL scripts were designed to remove the adapter sequences and determine the abundance of each distinct small RNA. We thank Lyudmila Sidorenko and Vicki Chandler for providing the plant material and Kan Nobuta for assistance with the computational methods.
Detailed analysis of a contiguous 22-Mb region of the maize genome.
Subject
View SamplesStudies using yeast have advanced our understanding of both replicative and chronological aging, leading to the discovery of longevity genes that have homologues in higher eukaryotes. Chronological lifespan in yeast is conventionally defined as the lifespan of a non-dividing cell. To date, this parameter has only been estimated under calorically restricted (CR) conditions, mimicked by starvation. Since post-mitotic cells in higher eukaryotes are rarely calorically-restricted, we sought to develop an alternative experimental system where non-dividing yeast would age chronologically, in the presence of excess nutrients. We report here on a system wherein alginate-encapsulated yeast are packed in a pH- and temperature-controlled bioreactor, then continuously fed non-limiting substrate for extended periods of time. We present demographic, physiological and genomic evidence indicating that after ~120 hrs, immobilized cells cease dividing, remain metabolically very active and retain >95% viability for periods of 17 days. Over the same time interval, starved planktonic cells, cultured using the same media, and also controlled for temperature and pH, retained < 1 % viability in both aerobic and anaerobic cultures,. Unlike planktonic yeast, continuously-fed immobilized cells hyper-accumulate glycogen. FACS analysis of SYTOX green-stained yeast confirms that immobilized cells completely arrest within 5 days of culture, and unlike starving planktonic cells, remain free thereafter of replicative stress and are non-apoptotic. This unusual state is supported by a global gene expression profile that is stable over time, repeatable across replicate experiments, and altogether distinct from planktonic cells cultured in the presence and absence of limiting nutrients. DNA expression profiling, performed here for the very first time on immobilized cells, reveals that glycolytic genes and their trans-acting regulatory elements are upregulated, as are genes involved in remodeling the cell wall and resisting stress; by contrast, many genes that promote cell cycle progression and carry out oxidative metabolism are repressed. Stress resistance transcription factor MSN4 and its upstream effector RIM15 are conspicuously upregulated in the immobilized state, suggesting that nutrient-sensing pathways may play a role in cell viability and longevity when yeast are immobilized and placed in prolonged culture under calorically-unrestricted conditions. The cell cycle arrest in the immobilized state is mediated by RIM 15. Over the time-course of our experiments, well-fed, non-diving immobilized cells do not appear to age.
Uncoupling reproduction from metabolism extends chronological lifespan in yeast.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An FGFR3/MYC positive feedback loop provides new opportunities for targeted therapies in bladder cancers.
Cell line
View SamplesTo better understand the molecular mechanisms underlying altered-FGFR3 oncogenic activity in bladder carcinomas, we made use of RT112 cell lines, which were derived from a human bladder tumor and endogenously expressed the FGFR3-TACC3 fusion protein, the growth and transformation of these cell lines being dependent on activated-FGFR3 activity. We conducted a gene expression analysis using Affymetrix DNA arrays in this cell line treated or not with FGFR3 siRNAs.
An FGFR3/MYC positive feedback loop provides new opportunities for targeted therapies in bladder cancers.
Cell line
View SamplesWe have generated over 80 million 32 nt reads generated from RNA samples isolated from the tip and base of a developing Mo17 leaf. A comparision of these data with the maize AGP resulted in the confirmation of approximately 88% of the maize filtered gene set Keywords: Transcriptome analysis Overall design: Examination of two different RNA samples from two different segments of a developing 3rd leaf
The B73 maize genome: complexity, diversity, and dynamics.
Specimen part, Subject
View SamplesAll above ground organs of higher plants are ultimately derived from shoot apical meristems (SAMs). The SAM exhibits distinctive structural organization, and monocot SAMs such as maize are comprised of two cell layers, a single cell layered tunica (L1) and a corpus (L2). Although recent research has revealed roles of these cell layers in the SAM, intra- and inter-cell-layer signaling networks involved in organ development remain largely unknown except for a few differentially expressed genes. Here, we used Illumnia technology to conduct RNA-seq of L1 and L2 cell layers in maize B73 maize shoot apical meristem. Overall design: Single sequencing library was constructed for L1 and L2 cell layer. 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.
The B73 maize genome: complexity, diversity, and dynamics.
Age, Subject
View SamplesHeterosis (hybrid vigor) refers to the superior performance of hybrid progeny relative to their parents. Although widely exploited in agriculture, the mechanisms responsible for heterosis are not well understood. As a monoecious organism, a given maize plant can be used as both male and female parents of crosses. Regardless of the cross direction, the maize inbred lines B73 and Mo17 produce hybrids that substantially out-perform their parents. These reciprocal hybrids differ phenotypically from each other despite having identical nuclear genomes. Consistent with these phenotypic observations, 30-50% of genes were differentially expressed between these reciprocal hybrids. An eQTL experiment conducted to better understand the regulation of gene expression in inbred and hybrid lines detected ~4,000 eQTL associations. The majority of these eQTL act in trans to regulate expression of genes on other chromosomes. Surprisingly, many of the trans-eQTL, when heterozygous, differentially regulated transcript accumulation in a manner consistent with gene expression in the hybrid being regulated exclusively by the paternally transmitted allele. The design of the eQTL experiment controlled for cytoplasmic and maternal effects, suggesting that widespread paternal genomic imprinting contributes to the regulation of gene expression in maize hybrids. Keywords: eQTL, parent-of-origin Overall design: GPL4521 - SAM1.2 (Reciprocal Hybrid Comparison): Six replications of B73xMo17 and Mo17xB73 were grown in growth chambers to tightly control environmental variation. Seeds from each genotype were taken from a single source (ear) for all six replications. Within each replication, genotypes were randomly assigned growth locations. Six healthy seedlings for each genotype and replication were harvested at two weeks of age. For each replication, B73xMo17 and Mo17xB73 were hybridized to the SAM1.2 microarray (GPL4521) using a randomized, alternate dye assignment. GPL3333 - SAM1.1 and GPL3538 - SAM3.0 (eQTL Experiment): Four biological replications of the RIL, B73xRIL, and Mo17xRIL cross-types were planted in growth chambers using seed from a single source for each genotype. Each RIL and its crosses onto B73 and Mo17 were planted using a split-plot design with RIL group (RIL and its cross onto B73 and Mo17) as the whole-plot treatment factor and cross-type (RIL, B73xRIL, and Mo17xRIL) as the split-plot treatment factor. The whole-plot portion of the experiment was designed as a randomized complete block design with four replications carried out on four separate occasions in the same environment. For the split-plot portion of the design, twelve seedlings of each RIL and its crosses were randomized within two adjacent flats in a growth chamber (six healthy seedlings per genotype were randomly chosen and pooled at harvest). For each replication, RIL, B73xRIL, and Mo17xRIL cross-types were hybridized to custom cDNA microarrays using a loop design such that each loop included all pairwise comparisons between the RIL and its crosses with B73 and Mo17. Four biological replications were hybridized to the SAM1.1 (GPL3333) array and two of the four biological replications were hybridized to SAM3.0 (GPL3538). RNA samples were alternately labeled to provide dye balance within each loop and replication. GPL8734 - Gene Expression between two maize reciprocal hybrids Heterosis refers to the enhanced agronomic performance of a hybrid relative to its (usually) inbred parents. We have previously documented widespread differences in gene expression in the B73xMo17 hybrid relative to its inbred parents B73 and Mo17 (Swanson, et al., 2006, PNAS). The reciprocal B73xMo17 and Mo17xB73 hybrids are both highly heterotic, but despite having identical nuclear genomes exhibit statistically significant differences in multiple traits. RNA-seq experiment was conducted to compare the gene expression globally between the two reciprocal hybrids. 1 samples from B73XMo17 and Mo17XB73 RNAs were extracted from a single replication of 14-day-old B73xMo17 and Mo17xB73 seedlings. RNAs were purified using DNaseI treatment followed by cleanup with the RNeasy Plant Mini Kit (Qiagen, Valencia, CA) as per manufacturer instructions. Sequencing library construction was completed using the Illumina mRNA-Seq sample preparation kit. 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.
The B73 maize genome: complexity, diversity, and dynamics.
Age, Specimen part
View SamplesHomeobox genes of the Hox class are required for proper patterning of skeletal elements and play a role in cartilage differentiation. In transgenic mice with overexpression of Hoxd4 during cartilage development, we observed severe defects, namely physical instability of cartilage, accumulation of immature chondrocytes, and decreased maturation to hypertrophy. To define the molecular basis underlying these defects, we performed gene expression profiling using the Affymetrix microarray platform.
Microarray Analysis of Defective Cartilage in Hoxc8- and Hoxd4-Transgenic Mice.
Specimen part
View SamplesHomeobox genes of the Hox class are required for proper patterning of skeletal elements and play a role in cartilage differentiation. In transgenic mice with overexpression of Hoxc8 during cartilage development, we observed severe defects, namely physical instability of cartilage, accumulation of immature chondrocytes, and decreased maturation to hypertrophy. To define the molecular basis underlying these defects, we performed gene expression profiling using the Affymetrix microarray platform.
Microarray Analysis of Defective Cartilage in Hoxc8- and Hoxd4-Transgenic Mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
An MLL/COMPASS subunit functions in the C. elegans dosage compensation complex to target X chromosomes for transcriptional regulation of gene expression.
Sex, Disease
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