scholarly journals Data-driven detection of subtype-specific and differentially expressed genes

2019 ◽  
Author(s):  
Lulu Chen ◽  
Yingzhou Lu ◽  
Guoqiang Yu ◽  
Robert Clarke ◽  
Jennifer E. Van Eyk ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
De Novo ◽  
Statistical Significance ◽  
Differentially Expressed ◽  
Superior Performance ◽  
Distribution Model ◽  
Data Sets ◽  
Test Statistic ◽  
Detection Power ◽  
Cell Subtype

Tissue or cell subtype-specific and differentially-expressed genes (SDEGs) are defined as being differentially expressed in a particular tissue or cell subtype among multiple subtypes. Detecting SDEGs plays a critical rolse in molecularly characterizing and identifying tissue or cell subtypes, and facilitating supervised deconvolution of complex tissues. Unfortunately, classic differential analysis assumes a convenient null hypothesis and associated test statistic that is subtype-non-specific and thus, resulting in a high false positive rate and/or lower detection power with respect to particular subtypes. Here we introduce One-Versus-Everyone Fold Change (OVE-FC) test for detecting SDEGs. To assess the statistical significance of such test, we also propose the scaled test statistic OVE-sFC together with a mixture null distribution model and a tailored permutation scheme. Validated with realistic synthetic data sets on both type 1 error and detection power, OVE-FC/sFC test applied to two benchmark gene expression data sets detects many known and de novo SDEGs. Subsequent supervised deconvolution results, obtained using the SDEGs detected by OVE-FC/sFC test, showed superior performance in deconvolution accuracy when compared with popular peer methods.

scholarly journals De novo transcriptome sequencing and anthocyanin metabolite analysis reveals leaf color of Acer pseudosieboldianum in autumn

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yu-Fu Gao ◽  
Dong-Hui Zhao ◽  
Jia-Qi Zhang ◽  
Jia-Shuo Chen ◽  
Jia-Lin Li ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
De Novo ◽  
Regulatory Genes ◽  
Differentially Expressed ◽  
Anthocyanin Synthesis ◽  
Leaf Color ◽  
Metabolite Analysis ◽  
Color Formation ◽  
Content Change ◽  
Final Color

Abstract Background Leaf color is an important ornamental trait of colored-leaf plants. The change of leaf color is closely related to the synthesis and accumulation of anthocyanins in leaves. Acer pseudosieboldianum is a colored-leaf tree native to Northeastern China, however, there was less knowledge in Acer about anthocyanins biosynthesis and many steps of the pathway remain unknown to date. Results Anthocyanins metabolite and transcript profiling were conducted using HPLC and ESI-MS/MS system and high-throughput RNA sequencing respectively. The results demonstrated that five anthocyanins were detected in this experiment. It is worth mentioning that Peonidin O-hexoside and Cyanidin 3, 5-O-diglucoside were abundant, especially Cyanidin 3, 5-O-diglucoside displayed significant differences in content change at two periods, meaning it may be play an important role for the final color. Transcriptome identification showed that a total of 67.47 Gb of clean data were obtained from our sequencing results. Functional annotation of unigenes, including comparison with COG and GO databases, yielded 35,316 unigene annotations. 16,521 differentially expressed genes were identified from a statistical analysis of differentially gene expression. The genes related to leaf color formation including PAL, ANS, DFR, F3H were selected. Also, we screened out the regulatory genes such as MYB, bHLH and WD40. Combined with the detection of metabolites, the gene pathways related to anthocyanin synthesis were analyzed. Conclusions Cyanidin 3, 5-O-diglucoside played an important role for the final color. The genes related to leaf color formation including PAL, ANS, DFR, F3H and regulatory genes such as MYB, bHLH and WD40 were selected. This study enriched the available transcriptome information for A. pseudosieboldianum and identified a series of differentially expressed genes related to leaf color, which provides valuable information for further study on the genetic mechanism of leaf color expression in A. pseudosieboldianum.

scholarly journals RNA-Seq Transcriptome Analysis of Peripheral Blood From Cattle Infected With Mycobacterium bovis Across an Experimental Time Course

2021 ◽  
Vol 8 ◽  
Author(s):  
Kirsten E. McLoughlin ◽  
Carolina N. Correia ◽  
John A. Browne ◽  
David A. Magee ◽  
Nicolas C. Nalpas ◽  
...  
Keyword(s):  
Differentially Expressed Genes ◽  
Mycobacterium Bovis ◽  
Peripheral Blood ◽  
Post Infection ◽  
Time Course ◽  
De Novo ◽  
Differentially Expressed Gene ◽  
Differentially Expressed ◽  
Infection Time ◽  
Time Point

Bovine tuberculosis, caused by infection with members of the Mycobacterium tuberculosis complex, particularly Mycobacterium bovis, is a major endemic disease affecting cattle populations worldwide, despite the implementation of stringent surveillance and control programs in many countries. The development of high-throughput functional genomics technologies, including RNA sequencing, has enabled detailed analysis of the host transcriptome to M. bovis infection, particularly at the macrophage and peripheral blood level. In the present study, we have analysed the transcriptome of bovine whole peripheral blood samples collected at −1 week pre-infection and +1, +2, +6, +10, and +12 weeks post-infection time points. Differentially expressed genes were catalogued and evaluated at each post-infection time point relative to the −1 week pre-infection time point and used for the identification of putative candidate host transcriptional biomarkers for M. bovis infection. Differentially expressed gene sets were also used for examination of cellular pathways associated with the host response to M. bovis infection, construction of de novo gene interaction networks enriched for host differentially expressed genes, and time-series analyses to identify functionally important groups of genes displaying similar patterns of expression across the infection time course. A notable outcome of these analyses was identification of a 19-gene transcriptional biosignature of infection consisting of genes increased in expression across the time course from +1 week to +12 weeks post-infection.

Bioinformatic Analysis of Differentially Expressed Genes and Screening of Hub Genes in Uveal Melanoma Cells with BRCA1-Associated Protein 1 Related Protein 1 Depletion

2020 ◽  
Vol 16 (8) ◽  
pp. 1205-1218
Author(s):  
Wei Li ◽  
Aiqin Nie ◽  
Qiang Li ◽  
He Cao ◽  
Yinwei Song ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Differentially Expressed Genes ◽  
Uveal Melanoma ◽  
Wnt Signaling Pathway ◽  
Tumor Development ◽  
Bioinformatic Analysis ◽  
Melanoma Cells ◽  
Differentially Expressed ◽  
Data Sets ◽  
And Migration

Recent studies have found that chromosome 3 is frequently mutated in metastatic uveal melanoma (UVM), which leads to the loss of BAP1 expression or the weakening of BRCA1-associated protein 1 (BAP1) function and promotes metastasis of uveal melanoma cells. However, the specific signaling pathways that are affected by BAP1 depletion in uveal melanoma remain unclear. Our aim in this study was to verify the effect and regulatory mechanism of BAP1 on uveal melanoma. RT-qPCR and western blotting results showed that BAP1 was significantly down-regulated in OCM-1A cells treated with a BAP1 shRNA vector. MTT, cell scratch and transwell migration assays showed that low expression of BAP1 significantly promoted the proliferation and migration of UVM cells. A total of 269 up-regulated and 807 down-regulated genes were identified from the combined GSE110193 and GSE48863 data sets. These differentially expressed genes are mainly involved in the composition of extracellular matrix and the regulation of the Wnt signaling pathway and are closely related to the cell adhesion pathway. CXCL8, COL5A3, COL11A1, and COL12A1 were among the differentially expressed genes and are closely related to the prognosis of UVM. Therefore, the deletion of BAP1 is closely related to poor prognosis of UVM and is a risk factor for UVM metastasis. The potential targets of BAP1 include CXCL8, COL5A3, COL11A1, and COL12A1. It is believed that BAP1 regulates UVM cell adhesion through these four genes and ultimately regulates tumor development and migration.

scholarly journals A New Test Statistic Based on Shrunken Sample Variance for Identifying Differentially Expressed Genes in Small Microarray Experiments

2008 ◽  
Vol 2 ◽  
pp. BBI.S473 ◽  
Author(s):  
Akihiro Hirakawa ◽  
Yasunori Sato ◽  
Chikuma Hamada ◽  
Isao Yoshimura
Keyword(s):  
Differentially Expressed Genes ◽  
Differentially Expressed ◽  
Simulation Studies ◽  
Test Statistic ◽  
Microarray Experiments ◽  
Cancer Data ◽  
False Discovery ◽  
The Mean ◽  
Sample Variances ◽  
Better Than

Choosing an appropriate statistic and precisely evaluating the false discovery rate (FDR) are both essential for devising an effective method for identifying differentially expressed genes in microarray data. The t-type score proposed by Pan et al. (2003) succeeded in suppressing false positives by controlling the underestimation of variance but left the overestimation uncontrolled. For controlling the overestimation, we devised a new test statistic (variance stabilized t-type score) by placing shrunken sample variances of the James-Stein type in the denominator of the t-type score. Since the relative superiority of the mean and median FDRs was unclear in the widely adopted Significance Analysis of Microarrays (SAM), we conducted simulation studies to examine the performance of the variance stabilized t-type score and the characteristics of the two FDRs. The variance stabilized t-type score was generally better than or at least as good as the t-type score, irrespective of the sample size and proportion of differentially expressed genes. In terms of accuracy, the median FDR was superior to the mean FDR when the proportion of differentially expressed genes was large. The variance stabilized t-type score with the median FDR was applied to actual colorectal cancer data and yielded a reasonable result.

scholarly journals De novo assembly of expressed transcripts and analysis of pistil to identify genes involved in early stage of pollination in Liriodendron chinense

2017 ◽  
Author(s):  
Ming Li ◽  
Kun Wang ◽  
Rebecca Njeri Damaris ◽  
Pingfang Yang
Keyword(s):  
Pollen Tube ◽  
Sexual Reproduction ◽  
Differentially Expressed Genes ◽  
De Novo ◽  
Early Stage ◽  
Average Length ◽  
Differentially Expressed ◽  
Seed Setting ◽  
Sequencing Data ◽  
Liriodendron Chinense

Plant sexual reproduction is a complicated and a key biological process with profuse interactions between pollen and pistil. This process determines whether fertilization will be successful or not and thus affect the seed setting. To explore the reason why L. chinense has a low seed setting ratio, transcriptome analysis on pistils of L. chinense during pollination were conducted. After analyzing the sequencing data, 206,858 unigenes with an average length of 646 bp were generated using the assembled transcripts. Among total unigenes, 3844 genes which expression fold change during early stage of pollination was higher or lower than 10 were selected as significant differentially expressed genes. 54 differentially expressed genes involved in sexual reproduction processes including the regulation of pollen tube growth process and double fertilization process might be partially causing the low seed setting in L. chinense. These results indicated that the barrier between pollen tube and pistil might be the reason why L. chinense have low seed setting. This study might be helpful to understand why L. chinense has such a low seed setting ratio.

scholarly journals Inferring the genetic responses to acute drought stress across an ecological gradient

BMC Genomics ◽  
2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Jessica K. Devitt ◽  
Albert Chung ◽  
John J. Schenk
Keyword(s):  
Drought Stress ◽  
Differentially Expressed Genes ◽  
Target Genes ◽  
De Novo ◽  
Water Movement ◽  
Model Systems ◽  
Differentially Expressed ◽  
Model Organisms ◽  
Ecological Gradient ◽  
Genetic Responses

Abstract Background How do xerophytic species thrive in environments that experience extreme annual drought? Although critical to the survival of many species, the genetic responses to drought stress in many non-model organisms has yet to be explored. We investigated this question in Mentzelia section Bartonia (Loasaceae), which occurs throughout western North America, including arid lands. To better understand the genetic responses to drought stress among species that occur in different habitats, the gene expression levels of three species from Mentzelia were compared across a precipitation gradient. Two de novo reference transcriptomes were generated and annotated. Leaf and root tissues were collected from control and drought shocked plants and compared to one another for differential expression. A target-gene approach was also implemented to better understand how drought-related genes from model and crop species function in non-model systems. Results When comparing the drought-shock treatment plants to their respective control plants, we identified 165 differentially expressed clusters across all three species. Differentially expressed genes including those associated with water movement, photosynthesis, and delayed senescence. The transcriptome profiling approach was coupled with a target genes approach that measured expression of 90 genes associated with drought tolerance in model organisms. Comparing differentially expressed genes with a ≥ 2 log-fold value between species and tissue types showed significant differences in drought response. In pairwise comparisons, species that occurred in drier environments differentially expressed greater genes in leaves when drought shocked than those from wetter environments, but expression in the roots mostly produced opposite results. Conclusions Arid-adapted species mount greater genetic responses compared to the mesophytic species, which has likely evolved in response to consistent annual drought exposure across generations. Drought responses also depended on organ type. Xerophytes, for example, mounted a larger response in leaves to downregulate photosynthesis and senescence, while mobilizing carbon and regulating water in the roots. The complexity of drought responses in Mentzelia suggest that whole organism responses need to be considered when studying drought and, in particular, the physiological mechanisms in which plants regulate water, carbon, cell death, metabolism, and secondary metabolites.

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