scholarly journals The effects of aneuploidy on gene expression in a dosage series of maize chromosome arm 1L

2017 ◽  
Author(s):  
◽  
Adam Johnson

Aneuploidy is a class of genetic conditions involving an unbalanced number of chromosomes. The most familiar human aneuploid condition is trisomy 21, called Down syndrome. Aneuploid conditions necessarily involve a change in the dosage of those genes which are located on the varied chromosome. However, the dosage level of a gene does not automatically correspond to the amount of RNA or protein that will be produced in vivo. Based on previously published studies, the impact of chromosome dosage changes on the transcription of single genes may be direct, inverse, or anywhere in between; and genes may be impacted anywhere in the genome, not just on the varied chromosome. Using a maize model system, a dosage series of plants was produced in which sibling plants are identical, except for the copy number of chromosome arm 1L. These plants were grown until 45 days postgermination, at which point leaf tissue was collected for RNA extraction. This dosage series included 5 dosage levels for comparison: diploid, trisomic, tetrasomic, haploid, and disomic haploid. A second dosage series was grown up to day 55, and included diploid, monosomic, and trisomic. Using RNA sequencing, expression levels for all genes were determined. The results were analyzed in aggregate, allowing for a view of effects on the level of the whole transcriptome. Results suggest that dosage of genes on the varied chromosome region has some correlation with expression of those genes, though the change compared to a diploid is often partial. Inverse relationships between chromosome dosage and RNA expression of genes elsewhere in the genome are seen to occur. Both direct and inverse reactions were amplified by increased levels of genomic imbalance. The kinetics of interacting proteins and other cellular components, as described in the gene balance hypothesis, may be the mechanism leading to these responses. Using the same methods of analysis, similar phenomena were observed in aneuploid/euploid comparisons in other organisms. Partial dosage compensation and inverse effects were observed in published datasets from aneuploid yeast and mouse. A set of trisomics in Arabidopsis displayed the same effects, though to a different extent in different trisomies. Using a published database of transcription factors, the responses of genes to dosage changes of their regulators was analyzed. A number of cascade effects were observed, in which inverse relationships of transcription factor dosage and target gene expression occurred sequentially, disrupting normal regulation of several genes in a network by changing the dosage of a single component.

2021 ◽  
Vol 11 (11) ◽  
pp. 4723
Author(s):  
Rosaria Scudiero ◽  
Chiara Maria Motta ◽  
Palma Simoniello

The cleidoic eggs of oviparous reptiles are protected from the external environment by membranes and a parchment shell permeable to water and dissolved molecules. As a consequence, not only physical but also chemical insults can reach the developing embryos, interfering with gene expression. This review provides information on the impact of the exposure to cadmium contamination or thermal stress on gene expression during the development of Italian wall lizards of the genus Podarcis. The results obtained by transcriptomic analysis, although not exhaustive, allowed to identify some stress-reactive genes and, consequently, the molecular pathways in which these genes are involved. Cadmium-responsive genes encode proteins involved in cellular protection, metabolism and proliferation, membrane trafficking, protein interactions, neuronal transmission and plasticity, immune response, and transcription regulatory factors. Cold stress changes the expression of genes involved in transcriptional/translational regulation and chromatin remodeling and inhibits the transcription of a histone methyltransferase with the probable consequence of modifying the epigenetic control of DNA. These findings provide transcriptome-level evidence of how terrestrial vertebrate embryos cope with stress, giving a key to use in population survival and environmental change studies. A better understanding of the genes contributing to stress tolerance in vertebrates would facilitate methodologies and applications aimed at improving resistance to unfavourable environments.


2021 ◽  
Vol 22 (3) ◽  
pp. 1222
Author(s):  
Cristina Cuello ◽  
Cristina A. Martinez ◽  
Josep M. Cambra ◽  
Inmaculada Parrilla ◽  
Heriberto Rodriguez-Martinez ◽  
...  

This study was designed to investigate the impact of vitrification on the transcriptome profile of blastocysts using a porcine (Sus scrofa) model and a microarray approach. Blastocysts were collected from weaned sows (n = 13). A total of 60 blastocysts were vitrified (treatment group). After warming, vitrified embryos were cultured in vitro for 24 h. Non-vitrified blastocysts (n = 40) were used as controls. After the in vitro culture period, the embryo viability was morphologically assessed. A total of 30 viable embryos per group (three pools of 10 from 4 different donors each) were subjected to gene expression analysis. A fold change cut-off of ±1.5 and a restrictive threshold at p-value < 0.05 were used to distinguish differentially expressed genes (DEGs). The survival rates of vitrified/warmed blastocysts were similar to those of the control (nearly 100%, n.s.). A total of 205 (112 upregulated and 93 downregulated) were identified in the vitrified blastocysts compared to the control group. The vitrification/warming impact was moderate, and it was mainly related to the pathways of cell cycle, cellular senescence, gap junction, and signaling for TFGβ, p53, Fox, and MAPK. In conclusion, vitrification modified the transcriptome of in vivo-derived porcine blastocysts, resulting in minor gene expression changes.


BMC Cancer ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Michal Marczyk ◽  
Chunxiao Fu ◽  
Rosanna Lau ◽  
Lili Du ◽  
Alexander J. Trevarton ◽  
...  

Abstract Background Utilization of RNA sequencing methods to measure gene expression from archival formalin-fixed paraffin-embedded (FFPE) tumor samples in translational research and clinical trials requires reliable interpretation of the impact of pre-analytical variables on the data obtained, particularly the methods used to preserve samples and to purify RNA. Methods Matched tissue samples from 12 breast cancers were fresh frozen (FF) and preserved in RNAlater or fixed in formalin and processed as FFPE tissue. Total RNA was extracted and purified from FF samples using the Qiagen RNeasy kit, and in duplicate from FFPE tissue sections using three different kits (Norgen, Qiagen and Roche). All RNA samples underwent whole transcriptome RNA sequencing (wtRNAseq) and targeted RNA sequencing for 31 transcripts included in a signature of sensitivity to endocrine therapy. We assessed the effect of RNA extraction kit on the reliability of gene expression levels using linear mixed-effects model analysis, concordance correlation coefficient (CCC) and differential analysis. All protein-coding genes in the wtRNAseq and three gene expression signatures for breast cancer were assessed for concordance. Results Despite variable quality of the RNA extracted from FFPE samples by different kits, all had similar concordance of overall gene expression from wtRNAseq between matched FF and FFPE samples (median CCC 0.63–0.66) and between technical replicates (median expression difference 0.13–0.22). More than half of genes were differentially expressed between FF and FFPE, but with low fold change (median |LFC| 0.31–0.34). Two out of three breast cancer signatures studied were highly robust in all samples using any kit, whereas the third signature was similarly discordant irrespective of the kit used. The targeted RNAseq assay was concordant between FFPE and FF samples using any of the kits (CCC 0.91–0.96). Conclusions The selection of kit to purify RNA from FFPE did not influence the overall quality of results from wtRNAseq, thus variable reproducibility of gene signatures probably relates to the reliability of individual gene selected and possibly to the algorithm. Targeted RNAseq showed promising performance for clinical deployment of quantitative assays in breast cancer from FFPE samples, although numerical scores were not identical to those from wtRNAseq and would require calibration.


Author(s):  
Mandy Rauschner ◽  
Luisa Lange ◽  
Thea Hüsing ◽  
Sarah Reime ◽  
Alexander Nolze ◽  
...  

Abstract Background The low extracellular pH (pHe) of tumors resulting from glycolytic metabolism is a stress factor for the cells independent from concomitant hypoxia. The aim of the study was to analyze the impact of acidic pHe on gene expression on mRNA and protein level in two experimental tumor lines in vitro and in vivo and were compared to hypoxic conditions as well as combined acidosis+hypoxia. Methods Gene expression was analyzed in AT1 prostate and Walker-256 mammary carcinoma of the rat by Next Generation Sequencing (NGS), qPCR and Western blot. In addition, the impact of acidosis on tumor cell migration, adhesion, proliferation, cell death and mitochondrial activity was analyzed. Results NGS analyses revealed that 147 genes were uniformly regulated in both cell lines (in vitro) and 79 genes in both experimental tumors after 24 h at low pH. A subset of 25 genes was re-evaluated by qPCR and Western blot. Low pH consistently upregulated Aox1, Gls2, Gstp1, Ikbke, Per3, Pink1, Tlr5, Txnip, Ypel3 or downregulated Acat2, Brip1, Clspn, Dnajc25, Ercc6l, Mmd, Rif1, Zmpste24 whereas hypoxia alone led to a downregulation of most of the genes. Direct incubation at low pH reduced tumor cell adhesion whereas acidic pre-incubation increased the adhesive potential. In both tumor lines acidosis induced a G1-arrest (in vivo) of the cell cycle and a strong increase in necrotic cell death (but not in apoptosis). The mitochondrial O2 consumption increased gradually with decreasing pH. Conclusions These data show that acidic pHe in tumors plays an important role for gene expression independently from hypoxia. In parallel, acidosis modulates functional properties of tumors relevant for their malignant potential and which might be the result of pH-dependent gene expression.


2018 ◽  
Vol 115 (48) ◽  
pp. E11321-E11330 ◽  
Author(s):  
Jie Hou ◽  
Xiaowen Shi ◽  
Chen Chen ◽  
Md. Soliman Islam ◽  
Adam F. Johnson ◽  
...  

Changes in dosage of part of the genome (aneuploidy) have long been known to produce much more severe phenotypic consequences than changes in the number of whole genomes (ploidy). To examine the basis of these differences, global gene expression in mature leaf tissue for all five trisomies and in diploids, triploids, and tetraploids of Arabidopsis thaliana was studied. The trisomies displayed a greater spread of expression modulation than the ploidy series. In general, expression of genes on the varied chromosome ranged from compensation to dosage effect, whereas genes from the remainder of the genome ranged from no effect to reduced expression approaching the inverse level of chromosomal imbalance (2/3). Genome-wide DNA methylation was examined in each genotype and found to shift most prominently with trisomy 4 but otherwise exhibited little change, indicating that genetic imbalance is generally mechanistically unrelated to DNA methylation. Independent analysis of gene functional classes demonstrated that ribosomal, proteasomal, and gene body methylated genes were less modulated compared with all classes of genes, whereas transcription factors, signal transduction components, and organelle-targeted protein genes were more tightly inversely affected. Comparing transcription factors and their targets in the trisomies and in expression networks revealed considerable discordance, illustrating that altered regulatory stoichiometry is a major contributor to genetic imbalance. Reanalysis of published data on gene expression in disomic yeast and trisomic mouse cells detected similar stoichiometric effects across broad phylogenetic taxa, and indicated that these effects reflect normal gene regulatory processes.


2011 ◽  
Vol 40 (1) ◽  
pp. 124-128
Author(s):  
Sabine Wohlres-Viana ◽  
Mariana Cortes Boite ◽  
João Henrique Moreira Viana ◽  
Marco Antonio Machado ◽  
Luiz Sérgio de Almeida Camargo

The objectives of this work were to identify and to evaluate possible differences on gene expression of aquaporins and Na/K-ATPases transcripts between embryos in vivo and in vitro produced. For each group, 15 blastocysts distributed in three pools were used for RNA extraction followed by amplification and reverse transcription. The resulting cDNAs were submitted to Real-Time PCR, using the GAPDH gene as endogenous control. It was not possible to identify AQP1 transcripts. Relative expression of AQP3 (1.33 ± 0.78) and AQP11 (2.00 ± 1.42) were not different in blastocysts in vitro and in vivo produced. Na/K-ATPase α1 gene (2.25 ± 1.07) was overregulated whereas Na/K-ATPase β2 transcripts 0.40 ± 0.30) did not differ among blastocysts produced in vitro from those produced in vivo. Transcripts for gene AQP1 are not present in bovine blastocysts. In vitro culture system does not alter expression of genes AQP3, AQP11 and Na/K-ATPase β2 genes, however, it affects expression of Na/K-ATPase α1.


2000 ◽  
Vol 113 (11) ◽  
pp. 1841-1849 ◽  
Author(s):  
T. Misteli

Gene expression is a fundamental cellular process. The basic mechanisms involved in expression of genes have been characterized at the molecular level. A major challenge is now to uncover how transcription, RNA processing and RNA export are organized within the cell nucleus, how these processes are coordinated with each other and how nuclear architecture influences gene expression and regulation. A significant contribution has come from cell biological approaches, which combine molecular techniques with microscopy methods. These studies have revealed that the mammalian cell nucleus is a complex but highly organized organelle, which contains numerous subcompartments. I discuss here how two essential nuclear processes - transcription and pre-mRNA splicing - are spatially organized and coordinated in vivo, and how this organization might contribute to the control of gene expression. The dynamic nature of nuclear proteins and compartments indicates a high degree of plasticity in the cellular organization of nuclear functions. The cellular organization of transcription and splicing suggest that the morphology of nuclear compartments is largely determined by the activities of the nucleus.


2020 ◽  
Vol 28 (4) ◽  
pp. 327-334
Author(s):  
Mahan Mohammadi ◽  
Shiva Irani ◽  
Iman Salahshourifar ◽  
Jalil Hosseini ◽  
Afshin Moradi ◽  
...  

BACKGROUND AND AIM: Prostate cancer is the leading cause of death in many countries. It is important to diagnose the disease in the early stages. Current methods detect the disease with low specificity. Examining the expression of genes responsible for disease and their epigenetic regulators are good tools in this regard. MATERIAL AND METHODS: In this prospective case-control study, 40 Iranian patients with cancer, 40 Iranian patients with prostate hyperplasia, and 40 control samples were examined. After blood sampling from each individual, RNA extraction and cDNA synthesis, GSTP1, HDAC, DNMT3A, and DNMT3B expressions were measured in three understudy groups using specific primers and Real-Time PCR method. RESULTS: A reverse correlation was identified between loss of GSTP1 expression and overexpression of HDAC, DNMT3A, and DNMT3B (P value < 0.0001) with a beneficial pattern of cancer development with high efficiency. The significant decrease of GSTP1 expression in patients in comparison to the healthy controls and the elevated expression levels of the studied epigenetic regulators in PCA and BPH samples indicate the impact of the regulators on GSTP1 expression activity. CONCLUSION: This study showed that the measurement of combined GSTP1 and its epigenetic regulators’ expression could be used as suitable genetic markers for the detection and separation of healthy individuals from prostatic patient groups in the Iranian population. However, a similar study in a larger population of case and control could help us to distinguish between normal, benign, and malignant conditions.


2017 ◽  
Vol 29 (1) ◽  
pp. 185 ◽  
Author(s):  
B. C. S. Leao ◽  
N. A. S. Rocha Frigoni ◽  
P. C. Dall'Acqua ◽  
M. Ambrogi ◽  
G. B. Nunes ◽  
...  

This study was conducted to evaluate the impact of supplementation during in vitro maturation (IVM) with linolenic acid (ALA), l-carnitine (L-car), or the combination of both supplements on the embryo intracellular lipid content and cryotolerance, as well as in the embryo expression of genes involved in lipid metabolism (lipogenesis regulation: SCD1, FASN, and SREBP1; and β-oxidation pathway: CPT1B and CPT2). Cumulus-oocyte complexes (n = 1076) were IVM for 22 h at 38.5°C and 5% CO2 in air, in TCM-199 medium with bicarbonate, hormones, and 10% FCS (control group), supplemented with 100 μM ALA (ALA group), 5 mM L-car (L-car group), or a combination of 100 μM ALA + 5 mM L-car (ALA + L-car group). After IVF, presumptive zygotes were in vitro cultured in SOFaa medium supplemented with 5 mg mL−1 BSA and 2.5% FCS, at 38.5°C and 5% CO2 in air during 7 days. Cleavage and blastocyst rates were evaluated on Day 3 and 7, respectively (IVF = Day 0). At Day 7, the blastocysts were stained with the lipophilic dye Sudan Black B (n = 60), vitrified/warmed (n = 260; Ingámed® protocol, Maringa-PR, Brazil), or collected for analysis of gene expression (n = 180). Embryonic development were analysed by ANOVA and the multiple comparisons of means were determined by Tukey’s test. The embryonic re-expansion data were subjected to chi-square test and the differences in gene expression among groups were evaluated by Duncan’s multiple range test (P < 0.05). Data are presented as means ± standard error means. There was no effect (P > 0.05) of the supplements used during IVM on cleavage (79.54 ± 2.76% to 82.16 ± 1.13%) and blastocyst rates (29.03 ± 3.07% to 30.46 ± 2.01%). Similarly, the intracellular lipid content in Day-7 blastocysts (1.03 ± 0.04 to 1.15 ± 0.07 pixels) and the embryonic cryotolerance, assessed by the re-expansion rates after 24 h (67.3 to 78.3%) hatching rates after 48 h (11.5 to 25.5%) of post-warming culture, were unaffected (P > 0.05) by the supplements of IVM medium. Although the treatments did not alter (P > 0.05) the expression of CPT1B and CPT2 genes, the expression of FASN gene was decreased (P < 0.05) in the ALA group and the expression of SREBP1 gene was decreased (P < 0.05) in the ALA and L-car groups. The expression of the gene SCD1 was reduced (P < 0.05) in all treatments compared with the control group. Thus, despite the lack of effects of the treatments performed during IVM on the intracellular lipid content and cryotolerance of the embryos derived from the treated oocytes, a reduction in the expression of genes related to lipogenesis was observed in Day-7 blastocysts. These results suggest that treatments performed in the oocytes during IVM may have prolonged effects, affecting the subsequent expression of genes in embryos. Further studies are needed to determine the mechanisms related to the differentiation of the oocyte machinery during maturation. Financial support was provided by FAPESP (#2012/10084–4 and #2013/07382–6).


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lyess Allas ◽  
Sybille Brochard ◽  
Quitterie Rochoux ◽  
Jules Ribet ◽  
Cleo Dujarrier ◽  
...  

Abstract Histone methyltransferase EZH2 is upregulated during osteoarthritis (OA), which is the most widespread rheumatic disease worldwide, and a leading cause of disability. This study aimed to assess the impact of EZH2 inhibition on cartilage degradation, inflammation and functional disability. In vitro, gain and loss of EZH2 function were performed in human articular OA chondrocytes stimulated with IL-1β. In vivo, the effects of EZH2 inhibition were investigated on medial meniscectomy (MMX) OA mouse model. The tissue alterations were assayed by histology and the functional disabilities of the mice by actimetry and running wheel. In vitro, EZH2 overexpression exacerbated the action of IL-1β in chondrocytes increasing the expression of genes involved in inflammation, pain (NO, PGE2, IL6, NGF) and catabolism (MMPs), whereas EZH2 inhibition by a pharmacological inhibitor, EPZ-6438, reduced IL-1β effects. Ex vivo, EZH2 inhibition decreased IL-1β-induced degradation of cartilage. In vivo, intra-articular injections of the EZH2 inhibitor reduced cartilage degradation and improved motor functions of OA mice. This study demonstrates that the pharmacological inhibition of the histone methyl-transferase EZH2 slows the progression of osteoarthritis and improves motor functions in an experimental OA model, suggesting that EZH2 could be an effective target for the treatment of OA by reducing catabolism, inflammation and pain.


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