scholarly journals Cigarette Smoking-Associated Isoform Switching and 3-prime UTR Lengthening Via Alternative Polyadenylation

2021 ◽  
Author(s):  
Zhonghui Xu ◽  
John Platig ◽  
Sool Lee ◽  
Adel Boueiz ◽  
Rob Chase ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Cigarette Smoking ◽  
Differential Expression ◽  
Alternative Polyadenylation ◽  
The United States ◽  
Biological Pathways ◽  
Differentially Expressed ◽  
Gtpase Activity ◽  
Functional Sequence ◽  
Sequence Elements

Cigarette smoking accounts for approximately one in five deaths in the United States. Previous genomic studies have primarily focused on gene level differential expression to identify related molecular signatures and pathways, but the genome-wide effects of smoking on alternative isoform regulation and posttranscriptional modulation have not yet been described. We conducted RNA sequencing (RNA-seq) in whole-blood samples of 454 current and 767 former smokers in COPDGene Study. We assessed the association of current smoking with differential expression of genes and isoforms and differential usage of isoforms and exons. At 10% FDR, we detected 3,167 differentially expressed genes, 2,014 differentially expressed isoforms, 945 differentially used isoforms and 160 differentially used exons. Genes containing differentially used isoforms were enriched in biological pathways involving GTPase activity and innate immunity. The majority of these genes were not differentially expressed, thus not identifiable from conventional differential gene expression analysis. Isoform switch analysis revealed for the first time widespread 3-prime UTR lengthening associated with cigarette smoking, where current smokers were found to have higher expression and usage of isoforms with markedly longer 3-prime UTRs. The lengthening of 3-prime UTRs appears to be mediated through alternative usage of distal polyadenylation sites, and these extended 3-prime UTR regions are significantly enriched with functional sequence elements including adenylate-uridylate (AU)-rich elements, microRNA and RNA-protein binding sites. Expression quantitative trait locus analyses on differentially used 3-prime UTRs identified 79 known GWAS variants associated with multiple smoking-related human diseases and traits. Smoking elicits widespread transcriptional and posttranscriptional alterations with disease implications. It induces alternative polyadenylation (APA) events resulting in a switch towards the usage of isoforms with strikingly longer 3-prime UTRs in genes related to multiple biological pathways including GTPase activity and innate immunity. The extended 3-prime UTR regions are enriched with functional sequence elements facilitating post-transcriptional regulation of protein expression and mRNA stability. These findings warrant further studies on APA events as potential biomarkers and novel therapeutic targets for smoking-related diseases.

scholarly journals Differential Gene Expression between Fungal Mating Types Is Associated with Sequence Degeneration

2020 ◽  
Vol 12 (4) ◽  
pp. 243-258 ◽  
Author(s):  
Wen-Juan Ma ◽  
Fantin Carpentier ◽  
Tatiana Giraud ◽  
Michael E Hood
Keyword(s):  
Differential Expression ◽  
Differentially Expressed Genes ◽  
Mating Type ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Gc Content ◽  
Differentially Expressed ◽  
Mating Types ◽  
Sexual Antagonism ◽  
Recombination Suppression

Abstract Degenerative mutations in non-recombining regions, such as in sex chromosomes, may lead to differential expression between alleles if mutations occur stochastically in one or the other allele. Reduced allelic expression due to degeneration has indeed been suggested to occur in various sex-chromosome systems. However, whether an association occurs between specific signatures of degeneration and differential expression between alleles has not been extensively tested, and sexual antagonism can also cause differential expression on sex chromosomes. The anther-smut fungus Microbotryum lychnidis-dioicae is ideal for testing associations between specific degenerative signatures and differential expression because 1) there are multiple evolutionary strata on the mating-type chromosomes, reflecting successive recombination suppression linked to mating-type loci; 2) separate haploid cultures of opposite mating types help identify differential expression between alleles; and 3) there is no sexual antagonism as a confounding factor accounting for differential expression. We found that differentially expressed genes were enriched in the four oldest evolutionary strata compared with other genomic compartments, and that, within compartments, several signatures of sequence degeneration were greater for differentially expressed than non-differentially expressed genes. Two particular degenerative signatures were significantly associated with lower expression levels within differentially expressed allele pairs: upstream insertion of transposable elements and mutations truncating the protein length. Other degenerative mutations associated with differential expression included nonsynonymous substitutions and altered intron or GC content. The association between differential expression and allele degeneration is relevant for a broad range of taxa where mating compatibility or sex is determined by genes located in large regions where recombination is suppressed.

scholarly journals High heterogeneity undermines generalization of differential expression results in RNA-Seq analysis

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Weitong Cui ◽  
Huaru Xue ◽  
Lei Wei ◽  
Jinghua Jin ◽  
Xuewen Tian ◽  
...  
Keyword(s):  
Gene Expression ◽  
Differential Expression ◽  
Small Sample ◽  
Differentially Expressed ◽  
Cancer Type ◽  
Rna Seq ◽  
Sample Sizes ◽  
Large Sample ◽  
Expression Levels ◽  
Gene Expression Levels

Abstract Background RNA sequencing (RNA-Seq) has been widely applied in oncology for monitoring transcriptome changes. However, the emerging problem that high variation of gene expression levels caused by tumor heterogeneity may affect the reproducibility of differential expression (DE) results has rarely been studied. Here, we investigated the reproducibility of DE results for any given number of biological replicates between 3 and 24 and explored why a great many differentially expressed genes (DEGs) were not reproducible. Results Our findings demonstrate that poor reproducibility of DE results exists not only for small sample sizes, but also for relatively large sample sizes. Quite a few of the DEGs detected are specific to the samples in use, rather than genuinely differentially expressed under different conditions. Poor reproducibility of DE results is mainly caused by high variation of gene expression levels for the same gene in different samples. Even though biological variation may account for much of the high variation of gene expression levels, the effect of outlier count data also needs to be treated seriously, as outlier data severely interfere with DE analysis. Conclusions High heterogeneity exists not only in tumor tissue samples of each cancer type studied, but also in normal samples. High heterogeneity leads to poor reproducibility of DEGs, undermining generalization of differential expression results. Therefore, it is necessary to use large sample sizes (at least 10 if possible) in RNA-Seq experimental designs to reduce the impact of biological variability and DE results should be interpreted cautiously unless soundly validated.

scholarly journals A Practical Multifaceted Approach to Selecting Differentially Expressed Genes

2007 ◽  
Vol 3 ◽  
pp. 117693510700300
Author(s):  
Yingye Zheng ◽  
Margaret Pepe
Keyword(s):  
Differential Expression ◽  
Gene Selection ◽  
Error Rates ◽  
Cancer Prognosis ◽  
Differentially Expressed ◽  
Expression Array ◽  
Statistical Research ◽  
P Values ◽  
Control Error ◽  
Strength Of Evidence

Consider a gene expression array study comparing two groups of subjects where the goal is to explore a large number of genes in order to select for further investigation a subset that appear to be differently expressed. There has been much statistical research into the development of formal methods for designating genes as differentially expressed. These procedures control error rates such as the false detection rate or family wise error rate. We contend however that other statistical considerations are also relevant to the task of gene selection. These include the extent of differential expression and the strength of evidence for differential expression at a gene. Using real and simulated data we first demonstrate that a proper exploratory analysis should evaluate these aspects as well as decision rules that control error rates. We propose a new measure called the mp-value that quantifies strength of evidence for differential expression. The mp-values are calculated with a resampling based algorithm taking into account the multiplicity and dependence encountered in microarray data. In contrast to traditional p-values our mp-values do not depend on specification of a decision rule for their definition. They are simply descriptive in nature. We contrast the mp-values with multiple testing p-values in the context of data from a breast cancer prognosis study and from a simulation model.

Screening candidate microR-15a- IRAK2 regulatory pairs for predicting the response to Staphylococcus aureus-induced mastitis in dairy cows

2019 ◽  
Vol 86 (4) ◽  
pp. 425-431 ◽  
Author(s):  
Zhi Chen ◽  
Jingpeng Zhou ◽  
Xiaolong Wang ◽  
Yang Zhang ◽  
Xubin Lu ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Differential Expression ◽  
High Throughput Sequencing ◽  
Target Genes ◽  
Interleukin 1 ◽  
Differentially Expressed ◽  
Luciferase Reporter ◽  
Expression Of Genes ◽  
Chinese Holstein Cows ◽  
Reporter Assays

AbstractWe established a mastitis model using exogenous infection of the mammary gland of Chinese Holstein cows with Staphylococcus aureus and extracted total RNA from S. aureus-infected and healthy mammary quarters. Differential expression of genes due to mastitis was evaluated using Affymetrix technology and results revealed a total of 1230 differentially expressed mRNAs. A subset of affected genes was verified via Q-PCR and pathway analysis. In addition, Solexa high-throughput sequencing technology was used to analyze profiles of miRNA in infected and healthy quarters. These analyses revealed a total of 52 differentially expressed miRNAs. A subset of those results was verified via Q-PCR. Bioinformatics techniques were used to predict and analyze the correlations among differentially expressed miRNA and mRNA. Results revealed a total of 329 pairs of negatively associated miRNA/mRNA, with 31 upregulated pairs of mRNA and 298 downregulated pairs of mRNA. Differential expression of miR-15a and interleukin-1 receptor-associated kinase-like 2 (IRAK2), were evaluated by western blot and luciferase reporter assays. We conclude that miR-15a and miR-15a target genes (IRAK2) constitute potential miRNA–mRNA regulatory pairs for use as biomarkers to predict a mastitis response.

scholarly journals Integration of mRNA and miRNA Analysis Reveals the Molecular Mechanism of Cotton Response to Salt Stress

2021 ◽  
Vol 12 ◽  
Author(s):  
Jingjing Zhan ◽  
Yangyang Diao ◽  
Guo Yin ◽  
Muhammad Sajjad ◽  
Xi Wei ◽  
...  
Keyword(s):  
Salt Stress ◽  
Differential Expression ◽  
Signal Transduction Pathway ◽  
Differentially Expressed ◽  
Sequencing Data ◽  
Regulatory Relationship ◽  
Significant Differential Expression ◽  
Amplification Bias ◽  
Before And After ◽  
Increased Sensitivity

To identify the regulatory network of known and novel microRNAs (miRNAs) and their targets responding to salt stress, a combined analysis of mRNA libraries, small RNA libraries, and degradome libraries were performed. In this study, we used unique molecular identifiers (UMIs), which are more sensitive, accurate, and reproducible than traditional methods of sequencing, to quantify the number of molecules and correct for amplification bias. We identified a total of 312 cotton miRNAs using seedlings at 0, 1, 3, and 6 h after NaCl treatment, including 80 known ghr-miRNAs and 232 novel miRNAs and found 155 miRNAs that displayed significant differential expression under salt stress. Among them, fifty-nine differentially expressed miRNAs were simultaneously induced in two or three tissues, while 66, 11, and 19 were specifically expressed in the roots, leaves, and stems, respectively. It is indicated there were different populations of miRNAs against salt stress in roots, leaves and stems. 399 candidate targets of salt-induced miRNAs showed significant differential expression before and after salt treatment, and 72 targets of 25 miRNAs were verified by degradome sequencing data. Furthermore, the regulatory relationship of miRNA-target gene was validated experimentally via 5′RLM-RACE, proving our data reliability. Gene ontology and KEGG pathway analysis found that salt-responsive miRNA targets among the differentially expressed genes were significantly enriched, and mainly involved in response to the stimulus process and the plant hormone signal transduction pathway. Furthermore, the expression levels of newly identified miRNA mir1 and known miRNAs miR390 and miR393 gradually decreased when subjected to continuous salt stress, while overexpression of these miRNAs both increased sensitivity to salt stress. Those newly identified miRNAs and mRNA pairs were conducive to genetic engineering and better understanding the mechanisms responding to salt stress in cotton.

scholarly journals Differential expression of cyclin A2 in triple negative breast cancer.

2021 ◽  
Author(s):  
Shahan Mamoor
Keyword(s):  
Breast Cancer ◽  
Overall Survival ◽  
Differential Expression ◽  
Tumor Cells ◽  
Triple Negative Breast Cancer ◽  
Triple Negative ◽  
Differentially Expressed ◽  
Primary Tumors ◽  
Ductal Cells ◽  
Cyclin A2

Women diagnosed with triple negative breast cancer can benefit neither from endocrine therapy nor from HER2-targeted therapies (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding cyclin A2, CCNA2, when comparing the tumor cells of patients with triple negative breast cancer to normal mammary ductal cells (2). CCNA2 was also differentially expressed in bulk tumor in human breast cancer (3). CCNA2 mRNA was present at significantly increased quantities in TNBC tumor cells relative to normal mammary ductal cells. Analysis of human survival data revealed that expression of CCNA2 in primary tumors of the breast was correlated with overall survival in patients with basal-like type cancer, while within triple negative breast cancer, primary tumor expression of CCNA2 was correlated with overall survival in patients with basal-like 1, basal-like 2, and mesenchymal subtype disease. CCNA2 may be of relevance to initiation, maintenance or progression of triple negative breast cancers.

scholarly journals Differential expression of LIM domain binding 2 in cancers of the breast.

2021 ◽  
Author(s):  
Shahan Mamoor
Keyword(s):  
Breast Cancer ◽  
Differential Expression ◽  
Survival Data ◽  
Molecular Subtype ◽  
Differentially Expressed Gene ◽  
Normal Breast ◽  
Differentially Expressed ◽  
Lim Domain ◽  
Significant Differential Expression ◽  
Primary Tumors

Breast cancer affects women at relatively high frequency (1). We mined published microarray datasets (2, 3) to determine in an unbiased fashion and at the systems level genes most differentially expressed in the primary tumors of patients with breast cancer. We report here significant differential expression of the gene encoding LIM domain binding 2, LDB2, when comparing primary tumors of the breast to the tissue of origin, the normal breast. LDB2 mRNA was present at significantly lower quantities in tumors of the breast as compared to normal breast tissue. Analysis of human survival data revealed that expression of LDB2 in primary tumors of the breast was correlated with recurrence-free survival in patients with luminal A subtype cancers, demonstrating a relationship between primary tumor expression of a differentially expressed gene and patient survival outcomes influenced by molecular subtype. LDB2 may be of relevance to initiation, maintenance or progression of cancers of the female breast.

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