Profiling expression changes caused by a segmental aneuploid in maize meristem tissues
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ABSTRACT:
ORGANISM(S): Zea mays
PROVIDER: GSE19212 | GEO | 2010/01/01
SECONDARY ACCESSION(S): PRJNA120827
REPOSITORIES: GEO
Similar Datasets
Project description:Segmental aneuploidy refers to the relative excess or deficiency of specific chromosome regions. This condition results in gene dosage imbalance and often causes severe phenotypic alterations in plants and animals. The mechanisms by which gene dosage imbalance effects gene expression and phenotype are not completely clear. The effects of aneuploidy on the transcriptome may depend on the types of cells analyzed and on the developmental stage. We performed global gene expression profiling to determine the effects of segmental aneuploidy on gene expression levels in two different maize tissues and a detailed analysis of expression of 30 genes affected by aneuploidy in multiple maize tissues. Multiple genes demonstrated qualitative changes in gene expression due to aneuploidy, when the gene became ectopically expressed or erroneously transcriptionally silenced in aneuploids relative to wild type plants. Our data strongly suggested that quantitative changes in gene expression at developmental transition points caused by variation in gene copy number progressed through tissue development and resulted in stable qualitative changes in gene expression patterns. Thus, aneuploidy in maize results in alterations of gene expression patterns that differ between tissues and developmental stages of maize seedlings. RNA was extracted from meristem tissues of 14 day-old maize seedlings segregating for segmental trisome of a short arm of chromosome 5. There are three biological replicates of pooled wild-type siblings and three biological replicates of pooled DpDf plants. The DpDf plants are segmental aneuploids that contain three copies of the short arm of chromosome 5. These plants are all in the B73 inbred genetic background.
2010-01-01 | E-GEOD-19212 | biostudies-arrayexpress
Project description:ABSTRACT: BACKGROUND: While changes in chromosome number that result in aneuploidy are associated with phenotypic consequences such as Down syndrome and cancer, the molecular causes of specific phenotypes and genome-wide expression changes that occur in aneuploids are still being elucidated. RESULTS: We employed a segmental aneuploid condition in maize to study phenotypic and gene expression changes associated with aneuploidy. Maize plants that are trisomic for 90% of the short arm of chromosome 5 and monosomic for a small distal portion of the short arm of chromosome 6 exhibited a phenotypic syndrome that includes reduced stature, tassel morphology changes and the presence of knots on the leaves. The knotted-like homeobox gene knox10, which is located on the short arm of chromosome 5, was shown to be ectopically expressed in developing leaves of the aneuploid plants. Expression profiling revealed that ~40% of the expressed genes in the trisomic region exhibited the expected 1.5 fold increased transcript levels while the remaining 60% of genes did not show altered expression even with increased gene dosage. CONCLUSIONS: We found that the majority of genes with altered expression levels were located within the chromosomal regions affected by the segmental aneuploidy and exhibits dosage-dependent expression changes. A small number of genes exhibit higher levels of expression change not predicted by the dosage, or display altered expression even though they are not located in the aneuploid regions. Keywords: Genotype comparison of wild-type and segmental aneuploid
2008-01-24 | GSE10243 | GEO
Project description:Genomic imbalance caused by varying the dosage of individual chromosomes or chromosomal segments (aneuploidy) has more detrimental effects than altering the dosage of complete chromosome sets (ploidy). Previous analysis on RNA-sequencing data of varied dosage of various chromosomal regions in maize (Zea mays) revealed global modulation of gene expression both on the varied chromosome (cis) and the remainder of the genome (trans). Dysregulation of microRNA (miRNA) dosage has been reported to have profound deleterious effects in many species. miRNAs are preferentially retained as duplicates following whole-genome duplication in grass species and are postulated to be dosage-sensitive. However, little is known regarding the role of miRNAs under genomic imbalance. We examined the impact of increased and/or decreased dosage of 1 interstitial and 19 distal chromosomal regions in concert with a whole-genome ploidy series of haploid, diploid, triploid, and tetraploid via small RNA-sequencing of diploid and haploid maize mature leaf tissue to investigate the impact of aneuploidy and polyploidy on expression of miRNAs. In general, cis miRNAs in aneuploids present a predominant gene-dosage effect, whereas trans miRNAs trend toward the inverse level, although other types of responses including dosage compensation, increased effect, and decreased effect also occur. Significant correlations between expression levels of miRNAs and their targets were identified in aneuploids, indicating the regulatory role of miRNAs on gene expression triggered by genomic imbalance. The findings provide novel insights into understanding of gene balance from the aspect of the function of miRNAs.
2022-05-12 | GSE189317 | GEO
Project description:ABSTRACT: BACKGROUND: While changes in chromosome number that result in aneuploidy are associated with phenotypic consequences such as Down syndrome and cancer, the molecular causes of specific phenotypes and genome-wide expression changes that occur in aneuploids are still being elucidated. RESULTS: We employed a segmental aneuploid condition in maize to study phenotypic and gene expression changes associated with aneuploidy. Maize plants that are trisomic for 90% of the short arm of chromosome 5 and monosomic for a small distal portion of the short arm of chromosome 6 exhibited a phenotypic syndrome that includes reduced stature, tassel morphology changes and the presence of knots on the leaves. The knotted-like homeobox gene knox10, which is located on the short arm of chromosome 5, was shown to be ectopically expressed in developing leaves of the aneuploid plants. Expression profiling revealed that ~40% of the expressed genes in the trisomic region exhibited the expected 1.5 fold increased transcript levels while the remaining 60% of genes did not show altered expression even with increased gene dosage. CONCLUSIONS: We found that the majority of genes with altered expression levels were located within the chromosomal regions affected by the segmental aneuploidy and exhibits dosage-dependent expression changes. A small number of genes exhibit higher levels of expression change not predicted by the dosage, or display altered expression even though they are not located in the aneuploid regions. Experiment Overall Design: There are four biological replicates of pooled wild-type siblings and four biological replicates of pooled DpDf plants. The DpDf plants are segmental aneuploids that contain three copies of the short arm of chromosome 5. These plants are all in the B73 inbred genetic background.
2008-06-11 | E-GEOD-10243 | biostudies-arrayexpress
Project description:Aneuploidy has profound effects on an organism, typically more so than polyploidy, and the basis of this contrast is not fully understood. A dosage series of maize chromosome arm 1L was used to compare relative global gene expression in different types and degrees of aneuploidy to gain insight into how the magnitude of genomic imbalance as well as hypoploidy affect global gene expression. While previously available methods required a selective examination of specific genes, RNA sequencing provides a whole-genome view of gene expression in aneuploids. Most studies of global aneuploid effects have concentrated on trisomics because other types of aneuploids are difficult to produce in most model genetic organisms. The genetic toolkit of maize allows the examination of multiple ploidies and 1-4 doses of chromosome arms. Thus, a detailed examination of expression changes both on the varied chromosome arm and elsewhere in the genome is possible, in both hypoploids and hyperploids, compared with euploid controls. Previous studies observed the inverse trans effect, in which genes not varied in DNA dosage are expressed in a negative relationship to the varied chromosomal region. This response was also the major type of change found globally in this study. It was also found that the effects of aneuploidy are progressive, with more severe aneuploids producing effects of greater magnitude.
2020-02-17 | GSE134936 | GEO
Project description:To understand the molecular basis of Down syndrome pathogenesis, we performed a transcriptome analysis of nine different tissues in Ts65Dn, an established mouse model of human trisomy 21. Ts65Dn mice have segmental trisomy of mouse chromosome 16 with ca. 128 genes at dosage imbalance (Reeves et al. 1995). The Ts65Dn mouse is widely used as a model for studies of DS because it is at dosage imbalance for the orthologs of about half the 284 Chr21 genes. Ts65Dn mice have several features that directly parallel developmental anomalies of DS. We compare here the expression of 136 mouse orthologs of Chr21 genes, 77 of which are triplicated in Ts65Dn, in trisomic and euploid mice. <br> <br> We designed a mouse cDNA expression array interrogating 136 mmu21 genes. RNA pools from four adult male Ts65Dn mice and four male euploid littermates were prepared from cortex and dissected from three to four month-old mice. Directly labeled first strand cDNA probes from nine different tissues were hybridized to the arrays in replicated hybridizations. A total of 446 genes that are not triplicated in Ts65Dn mice served as controls. These included 62 mmu21 genes from MMU10, MMU17, and non-triplicated portions of MMU16, plus 384 randomly distributed mouse cDNAs from the Unigene collection.
2004-04-23 | E-MEXP-102 | biostudies-arrayexpress
Project description:The phenotypic consequences of the addition or subtraction of part of a chromosome is more severe than changing the dosage of the whole genome. By crossing diploid trisomies to a haploid inducer, we identified seventeen distal segmental haploid disomies that cover ~80% of the maize genome. Disomic haploids provide a level of genomic imbalance that is not ordinarily achievable in multicellular eukaryotes, allowing the impact to be stronger and more easily studied. Transcriptome size estimates revealed that a few disomies inversely modulate most of the transcriptome. Based on RNA sequencing, the expression levels of genes located on the varied chromosome arms (cis) in disomies ranged from being proportional to chromosomal dosage (dosage effect) to showing dosage compensation with no expression change with dosage. For genes not located on the varied chromosome arm (trans), an obvious trans-acting effect can be observed, with the majority showing a decreased modulation (inverse effect). The extent of dosage compensation of varied cis genes correlates with the extent of trans inverse effects across the 17 genomic regions studied. The results also have implications for the role of stoichiometry in gene expression, the control of quantitative traits, and the evolution of dosage-sensitive genes.
2021-02-22 | GSE156986 | GEO
Project description:Accessing the natural genetic diversity of species unveils hidden genetic traits, clarifies gene functions, and allows assessment of the generalizability of laboratory findings. One notable discovery made in Saccharomyces cerevisiae natural isolates is frequent (~20%) aneuploidy – an imbalance in chromosome copy numbers – that appears to contradict the significant fitness costs and transient nature reported for lab-engineered aneuploids. Here, we generated a proteomic resource and merged it with genomic and transcriptomic data for 796 euploid and aneuploid natural isolates. We found that natural and lab-generated aneuploids differ specifically at the proteome. In lab-generated aneuploids, some proteins, especially protein complex subunits, show reduced expression, yet the overall protein levels correspond to the aneuploid gene dosage. By contrast, in natural isolates, more than 70% of proteins encoded on aneuploid chromosomes are dosage-compensated, with average protein levels being shifted towards the euploid state chromosome-wide. At the molecular level, we detect an induction of structural components of the proteasome, increased levels of ubiquitination, and reveal an interdependency of protein turnover rates and attenuation. Our study thus highlights the role of protein turnover in mediating aneuploidy tolerance, and demonstrates the utility of exploiting the natural diversity of species to reach generalizable molecular insights into complex biological processes. This resource provides the SILAC dataset from this work.
2024-03-13 | PXD048219 | Pride
Project description:Chromosomal instability (CIN) is thought to be a source of mutability in human cancer. However, CIN is highly deleterious for the cell, and the resulting aneuploidy induces metabolic stress and compromises cell fitness. Here we utilized the X-chromosome dosage compensation mechanism and changes in X-chromosome number to demonstrate in Drosophila epithelial cells the causal relationship between CIN, aneuploidy, gene dosage imbalance and tumorigenesis. Whereas the harmful effects of CIN can be buffered by resetting the X-chromosome dosage compensation to compensate for changes in X-chromosome number, interfering with the mechanisms of dosage compensation suffices to induce tumorigenesis. In addition, multiple mechanisms buffer the deleterious effects of CIN including DNA-damage repair, activation of the p38 signalling pathway, and induction of cytokine expression to promote compensatory cell proliferation. These data reveal a key role of gene dosage imbalances to CIN-induced programmed cell death and tumorigenesis and the existence of robust compensatory mechanisms.
2016-05-23 | GSE71242 | GEO
Project description:We examined the impact of both increased and decreased dosage of fifteen distal and one interstitial chromosomal regions via RNA-seq of maize mature leaf tissue to reveal new aspects of genomic imbalance. The results indicate that significant changes in gene expression in aneuploids occur both on the varied chromosome (cis) and the remainder of the genome (trans), with a wider spread of modulation compared with the whole-ploidy series of haploid to tetraploid. In general, cis genes in aneuploids range from a gene-dosage effect to dosage compensation, whereas for trans genes the most common effect is an inverse correlation in that expression is modulated towards the opposite direction of the varied chromosomal dosage, although positive modulations also occur. Furthermore, this analysis revealed the existence of increased and decreased effects in which expression of many genes under genome imbalance are modulated towards the same direction regardless of increased or decreased chromosomal dosage, which is predicted from kinetic considerations of multicomponent molecular interactions. The findings provide novel insights into understanding mechanistic aspects of gene regulation.
2021-02-02 | GSE149186 | GEO