Variation In Transcript Levels Research Articles

Regional adiposity and insulin sensitivity - interactions with menopause and HIV in middle-aged Black African women.

To explore depot-specific functional aspects of adipose tissue, examining the putative role for menopause and HIV status on insulin sensitivity (SI) and beta-cell function in Black South African women. Women (n = 92) from the Middle-Aged Soweto Cohort, including premenopausal HIV-negative (n = 21); premenopausal women living with HIV (WLWH; n = 11); postmenopausal HIV-negative (n = 42); postmenopausal WLWH (n = 18) underwent the following tests: body composition (dual energy x-ray absorptiometry); fasting bloods for sex hormones, inflammation and adipokines; frequently sampled intravenous glucose tolerance test for SI and beta-cell function (disposition index, DI); abdominal (aSAT) and gluteal subcutaneous adipose tissue (gSAT) biopsies for cell size and mRNA expression of adipokines, inflammation, and estrogen receptors [ER]. Depot-specific associations between gene expression and insulin parameters did not differ by HIV or menopause status. Pooled analysis showed significant models for SI (P = 0.002) and DI (P = 0.003). Higher SI was associated with lower leptin and CD11c expression in aSAT and higher adiponectin in gSAT. Higher DI was associated with higher aSAT and gSAT expression of adiponectin, LPL, ERα, and PPARγ, and lower leptin in aSAT. WLWH had higher expression of adiponectin and lower expression of leptin in both aSAT (P = 0.002 and P = 0.005) and gSAT (P = 0.004 and P = 0.002), respectively, and a larger proportion of smaller cells in aSAT (P < 0.001). Insulin sensitivity and beta cell function were distinctively associated with aSAT and gSAT. While menopause did not influence these relationships, HIV had a significant effect on adipose tissue, characterised by variations in cell size distribution and transcript levels within the depots.

Species-wide quantitative transcriptomes and proteomes reveal distinct genetic control of gene expression variation in yeast

Gene expression varies between individuals and corresponds to a key step linking genotypes to phenotypes. However, our knowledge regarding the species-wide genetic control of protein abundance, including its dependency on transcript levels, is very limited. Here, we have determined quantitative proteomes of a large population of 942 diverse natural Saccharomyces cerevisiae yeast isolates. We found that mRNA and protein abundances are weakly correlated at the population gene level. While the protein coexpression network recapitulates major biological functions, differential expression patterns reveal proteomic signatures related to specific populations. Comprehensive genetic association analyses highlight that genetic variants associated with variation in protein (pQTL) and transcript (eQTL) levels poorly overlap (3%). Our results demonstrate that transcriptome and proteome are governed by distinct genetic bases, likely explained by protein turnover. It also highlights the importance of integrating these different levels of gene expression to better understand the genotype-phenotype relationship.

Abstract 6971: The impact of lecithin retinol acyltransferase in squamous cell carcinoma: Tissue formation, cell mechanics, and gene transcription

Abstract Squamous cell carcinoma, along with several other cancers, has been found to lack expression of lecithin retinol acyltransferase (LRAT), a protein which catalyzes retinol esterification and thereby mediates retinoic acid biosynthesis. When expression of LRAT was reintroduced in squamous cell carcinoma, the protein promoted cell differentiation in addition to retinoid status normalization—whether this effect was dependent on the known enzymatic activity of LRAT in retinol esterification, versus another function, has not yet been established. Cell elasticity differences have also been reported between squamous cell carcinoma and normal keratinocytes. In this study, the role of LRAT expression and activity was evaluated in human squamous cell carcinoma cell line SCC13. LRAT was integrated into the genome of SCC13 via retroviral transduction, both as wild-type LRAT and LRAT with a cysteine-to-serine mutation at the active site for retinol esterification (C161-S). In these transformed cell lines, LRAT promoted formation of a cohesive sheet of tissue which remained intact after its removal from the tissue culture plastic surface, as evaluated at two weeks post-confluence. SCC13 alone produced tissue which easily fragmented during this scraping assay. In an evaluation of cell elasticity with shear modulation force microscopy, relative cell modulus measurements of pre-confluent SCC13 with LRAT expression were found to be significantly greater and consistent with the cell modulus of human keratinocytes (DO33). These effects persisted with mutation of the retinol esterification active site, suggesting that LRAT possesses an additional function which has yet to be described. Variation in transcription levels of multiple genes—urokinase-type plasminogen activator, plasminogen activator inhibitor 1, tissue inhibitor of metalloproteinases 1, and kallikrein 5—was also found based on LRAT expression and level of confluence. These findings suggest that the presence of LRAT influences tissue formation, cell elasticity, and gene transcription in SCC13. Citation Format: Emily Peterson, Kuan-Che Feng, Jay Gao, Miriam Rafailovich, Marcia Simon. The impact of lecithin retinol acyltransferase in squamous cell carcinoma: Tissue formation, cell mechanics, and gene transcription [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6971.

Changes in Gravitaxis and Gene-Expression in an Euglena gracilis Culture over Time.

Age-dependent changes in the transcription levels of 5-day-old Euglena gracilis cells, which showed positive gravitaxis, 6-day-old cells without gravitactic orientation, and older cells (9- and 11-day-old, which displayed a precise negative gravitaxis) were determined through microarray analysis. Hierarchical clustering of four independent cell cultures revealed pronounced similarities in transcription levels at the same culture age, which proves the reproducibility of the cultivation method. Employing the non-oriented cells from the 6-day-old culture as a reference, about 2779 transcripts were found to be differentially expressed. While positively gravitactic cells (5-day-old culture) showed only minor differences in gene expression compared to the 6-day reference, pronounced changes of mRNAs (mainly an increase) were found in older cells compared to the reference culture. Among others, genes coding for adenylyl cyclases, photosynthesis, and metabolic enzymes were identified to be differentially expressed. The investigated cells were grown in batch cultures, so variations in transcription levels most likely account for factors such as nutrient depletion in the medium and self-shading. Based on these findings, a particular transcript (e.g., transcript 19556) was downregulated using the RNA interference technique. Gravitaxis and phototaxis were impaired in the transformants, indicating the role of this transcript in signal transduction. Results of the experiment are discussed regarding the increasing importance of E. gracilis in biotechnology as a source of valuable products and the possible application of E. gracilis in life-support systems.

The impact of agrochemical pollutant mixtures on the selection of insecticide resistance in the malaria vector Anopheles gambiae: insights from experimental evolution and transcriptomics

BackgroundThere are several indications that pesticides used in agriculture contribute to the emergence and spread of resistance of mosquitoes to vector control insecticides. However, the impact of such an indirect selection pressure has rarely been quantified and the molecular mechanisms involved are still poorly characterized. In this context, experimental selection with different agrochemical mixtures was conducted in Anopheles gambiae. The multi-generational impact of agrochemicals on insecticide resistance was evaluated by phenotypic and molecular approaches.MethodsMosquito larvae were selected for 30 generations with three different agrochemical mixtures containing (i) insecticides, (ii) non-insecticides compounds, and (iii) both insecticide and non-insecticide compounds. Every five generations, the resistance of adults to deltamethrin and bendiocarb was monitored using bioassays. The frequencies of the kdr (L995F) and ace1 (G119S) target-site mutations were monitored every 10 generations. RNAseq was performed on all lines at generation 30 in order to identify gene transcription level variations and polymorphisms associated with each selection regime.ResultsLarval selection with agrochemical mixtures did not affect bendiocarb resistance and did not select for ace1 mutation. Contrastingly, an increased deltamethrin resistance was observed in the three selected lines. Such increased resistance was not majorly associated with the presence of kdr L995F mutation in selected lines. RNA-seq identified 63 candidate resistance genes over-transcribed in at least one selected line. These include genes coding for detoxification enzymes or cuticular proteins previously associated with insecticide resistance, and other genes potentially associated with chemical stress response. Combining an allele frequency filtering with a Bayesian FST-based genome scan allowed to identify genes under selection across multiple genomic loci, supporting a multigenic adaptive response to agrochemical mixtures.ConclusionThis study supports the role of agrochemical contaminants as a significant larval selection pressure favouring insecticide resistance in malaria vectors. Such selection pressures likely impact kdr mutations and detoxification enzymes, but also more generalist mechanisms such as cuticle resistance, which could potentially lead to cross-tolerance to unrelated insecticide compounds. Such indirect effect of global landscape pollution on mosquito resistance to public health insecticides deserves further attention since it can affect the nature and dynamics of resistance alleles circulating in malaria vectors and impact the efficacy of control vector strategies.

Tissue-specific impacts of aging and genetics on gene expression patterns in humans

Age is the primary risk factor for many common human diseases. Here, we quantify the relative contributions of genetics and aging to gene expression patterns across 27 tissues from 948 humans. We show that the predictive power of expression quantitative trait loci is impacted by age in many tissues. Jointly modelling the contributions of age and genetics to transcript level variation we find expression heritability (h2) is consistent among tissues while the contribution of aging varies by >20-fold with {R}_{{{{{{{{rm{age}}}}}}}}}^{2} ; > ;{h}^{2} in 5 tissues. We find that while the force of purifying selection is stronger on genes expressed early versus late in life (Medawar’s hypothesis), several highly proliferative tissues exhibit the opposite pattern. These non-Medawarian tissues exhibit high rates of cancer and age-of-expression-associated somatic mutations. In contrast, genes under genetic control are under relaxed constraint. Together, we demonstrate the distinct roles of aging and genetics on expression phenotypes.

Characterization of Insecticide Response-Associated Transcripts in the Colorado Potato Beetle: Relevance of Selected Cytochrome P450s and Clothianidin

Simple SummaryThe Colorado potato beetle is an insect pest that can significantly harm potato crops. Various approaches are available to mitigate its damages including the use of insecticides. Unfortunately, its ability to develop resistance towards these compounds is substantial, and understanding the basis of this process is of utmost importance to design strategies to limit the impact of this insect. This work thus aims at quantifying the expression of key transcripts coding for proteins associated with insecticide resistance in Colorado potato beetles exposed to four insecticides. Significant variations were observed, notably in insects exposed to the insecticide clothianidin. Interestingly, subsequent reduction of endogenous levels of selected targets modulated by clothianidin was associated with increased insect susceptibility to this neonicotinoid. These results further highlight molecular players with potential relevance for insecticide resistance, and introduce novel targets that underlie clothianidin resistance in the Colorado potato beetle.The Colorado potato beetle (Leptinotarsa decemlineata (Say)) is known for its capacity to cause significant damages to potato crops worldwide. Multiple approaches have been considered to limit its spread including the use of a diverse arsenal of insecticides. Unfortunately, this insect frequently develops resistance towards these compounds. Investigating the molecular bases underlying the response of L. decemlineata against insecticides is of strong interest to ultimately devise novel and targeted approaches aimed at this pest. This work aimed to characterize, via qRT-PCR, the expression status of targets with relevance to insecticide response, including ones coding for cytochrome P450s, glutathione s-transferases, and cuticular proteins, in L. decemlineata exposed to four insecticides; chlorantraniliprole, clothianidin, imidacloprid, and spinosad. Modulation of levels associated with transcripts coding for selected cytochrome P450s was reported in insects treated with three of the four insecticides studied. Clothianidin treatment yielded the most variations in transcript levels, leading to significant changes in transcripts coding for CYP4c1, CYP4g15, CYP6a13, CYP9e2, GST, and GST-1-Like. Injection of dsRNA targeting CYP4c1 and CYP9e2 was associated with a substantial decrease in expression levels and was, in the case of the latter target, linked to a greater susceptibility of L. decemlineata towards this neonicotinoid, supporting a potential role for this target in clothianidin response. Overall, this data further highlights the differential expression of transcripts with potential relevance in insecticide response, as well as generating specific targets that warrant investigation as novel dsRNA-based approaches are developed against this insect pest.

Environment-driven shifts in interindividual variation and phenotypic integration within subnetworks of the mussel transcriptome and proteome.

The environment can alter the magnitude of phenotypic variation among individuals, potentially influencing evolutionary trajectories. However, environmental influences on variation are complex and remain understudied. Populations in heterogeneous environments might exhibit more variation, the amount of variation could differ between benign and stressful conditions, and/or variation might manifest in different ways among stages of the gene‐to‐protein expression cascade or among physiological functions. Here, we explore these three issues by quantifying patterns of inter‐individual variation in both transcript and protein expression levels among California mussels, Mytilus californianus Conrad. Mussels were exposed to five ecologically relevant treatments that varied in the mean and interindividual heterogeneity of body temperature. To target a diverse set of physiological functions, we assessed variation within 19 expression subnetworks, including canonical stress‐response pathways and empirically derived coexpression clusters that represent a diffuse set of cellular processes. Variation in expression was particularly pronounced in the treatments with high mean and heterogeneous body temperatures. However, with few exceptions, environment‐dependent shifts of variation in the transcriptome were not reflected in the proteome. A metric of phenotypic integration provided evidence for a greater degree of constraint on relative expression levels (i.e., stronger correlation) within expression subnetworks in benign, homogeneous environments. Our results suggest that environments that are more stressful on average – and which also tend to be more heterogeneous – can relax these expression constraints and reduce phenotypic integration within biochemical subnetworks. Context‐dependent “unmasking” of functional variation may contribute to interindividual differences in physiological phenotype and performance in stressful environments.

Expression analysis of opaque2, crtRB1 and shrunken2 genes during different stages of kernel development in biofortified sweet corn

Sweet corn is a popular food worldwide. Traditional shrunken2 (sh2)-derived sweet corn possesses low lysine (0.150–0.250%), tryptophan (0.030–0.040%) and provitamin-A (proA: 3–4 μg/g). Here transcript profiles of a newly developed 12 sh2-based sweet corn inbreds possessing mutant opaque2 (o2) and β-carotene hydroxylase (crtRB1) genes were analyzed during three stages of kernel development viz., 20-, 24- and 28- days after pollination (DAP). Introgressed inbreds had higher lysine (0.309%), tryptophan (0.077%) and proA (17.28 μg/g). Across stages of kernel development, transcript levels of mutant sh2, o2 and crtRB1 genes were significantly lower than the wild type (sh2+, o2+ and crtRB1+) alleles. Among genes, sh2 had the highest level of transcripts accumulation followed by crtRB1 and o2. While o2 and crtRB1 transcripts attained peaks at 24-DAP, the highest peak for sh2 was recorded at 28-DAP. Strong negative correlation (r = −0.99 to −0.71) was observed between the transcripts and corresponding nutrients. The study provided insight of complex regulation of sh2, o2 and crtRB1 genes during various stages of kernel development. This is a first of its kind study to analyze the transcript level variation of mutant allele of sh2, o2 and crtRB1 genes among novel biofortified sweet corn genotypes.

Abstract PD14-01: Comprehensive molecular characterization of patients with metastatic invasive lobular carcinoma (ILC): Using real-world data to describe this unique clinical entity

Abstract Background: ILC is the second most common type of breast cancer and accounts for approximately 10% of all invasive breast cancers. A hallmark of ILC is the lack of E-cadherin (CDH1) expression, which is frequently used to discriminate between lesions with borderline ductal and lobular histologies. While the genomic landscape of primary ILCs has been well described, less is known about patients (pts) with metastatic-ILC (mILC). Better characterization of the genomic landscape associated with mILC is critical for identifying biomarkers that may provide new insight into ILC tumor biology and ultimately improve long-term outcomes in pts with mILC. Methods: We retrospectively analyzed de-identified next-generation sequencing (NGS) data from 150 advanced/metastatic pts with ILC and 51 with mixed lobular/ductal histology, defined using the histology of the sequenced biopsy. Diagnoses were abstracted from pathology reports submitted at the time of sequencing. We used the stage documented closest in time to biopsy collection, and samples were excluded if the staging date was unknown or exceeded 180 days after the biopsy date. Our dataset consisted of samples that were molecularly profiled using the Tempus xT solid tumor assay (DNA-seq of 595-648 genes at 500x coverage, full-transcriptome RNA-seq). The mutations identified for this study include somatic single-nucleotide variants and insertions/deletions. Furthermore, we examined the co-mutational landscape of CDH1-mutant disease and investigated transcript-level expression variation. Results: Mutations in CDH1 occurred in 65.3% of all mILC samples (98/150). CDH1 expression was similar between CDH1-mutant and WT mILC samples (Wilcoxon rank sum test, p=0.8). The median tumor mutational burden (TMB) score was significantly higher in CDH1-mutant samples (Wilcoxon rank-sum test, p=0.010). CDH1-mutant samples were more likely to have a high TMB (≥10 mutations/MB) when compared with the wild-type CDH1 cohort (10% vs. 6.2%), but this difference was not statistically significant (Fisher’s Exact test, p=0.5). Additionally, we observed that the ER+ subtype was more frequent in CDH1-mutant samples, although this difference was not statistically significant (97% vs 88%; Fisher’s exact test, p=0.063). PIK3CA mutations were enriched in CDH1-mutant mILC (Table 1). TBX3 and NCOR1 mutations were also mildly enriched in CDH1-mutant mILC, but these results were not significant when correcting for multiple testing (Table 1). CDH1-mutant mixed histology pts had lower CDH1 expression than WT pts (p&amp;lt;0.001, Wilcoxon rank sum exact test). PIK3CA mutations were enriched in CDH1-mutant mixed histology pts, but this difference was not statistically significant (50% vs. 31%; p=0.3, Fisher’s exact test). Log10 CDH1 expression across all mILC pts was lower than in mixed histology pts (3.01 vs 3.53; p&amp;lt;0.001, Wilcoxon rank-sum test). Conclusions: Our real-world dataset illustrates that the molecular landscape of CDH1-mutant mILC pts is distinct from CDH1-WT mILC pts. Additionally, mILC differs from mixed histology at a transcriptional level, with lower CDH1 expression regardless of CDH1 mutational status. Our findings suggest a use for CDH1 RNA expression levels in reclassifying mixed histology samples as mILC. Additionally, therapies targeting PIK3CA may be further investigated for their actionability in CDH1-mutant mILC cases. Table 1.Frequency of co-mutations in CDH1-mutant vs. WT mILC cohortsGenesCDH1-mutant (n=98)CDH1 WT (n=52)p-value1q-value2n (%)n (%)PIK3CA53 (54%)6 (12%)&amp;lt;0.001&amp;lt;0.001TBX313 (13%)0 (0%)0.0040.13NCOR111 (11%)0 (0%)0.0090.21Pearson’s Chi-squared test; Fisher’sexact test. 2Falsediscovery rate correction for multiple testing Citation Format: Andrew A Davis, Amir Behdad, Kayla Viets Layng, Firas Wehbe, Lorenzo Gerratana, Elizabeth Mauer, Alex Barrett, Ami N Shah, Paolo D’Amico, Lisa Flaum, William J Gradishar, Leonidas C Platanias, Massimo Cristofanilli. Comprehensive molecular characterization of patients with metastatic invasive lobular carcinoma (ILC): Using real-world data to describe this unique clinical entity [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD14-01.

Association of decreased sperm motility and increased seminal plasma IGF-I, IGF-II, IGFBP-2, and PSA levels in infertile men.

Previous studies have suggested the involvement of serum insulin-like growth factors (IGFs) and IGF binding proteins (IGFBPs) in the regulation of the female reproductive system. Little is known of these peptides in the seminal plasma (SP) of men and their potential effects on fertility. We assessed SP levels of these peptides in infertile men with low sperm motility (asthenozoospermic; AZ) and low sperm counts (oligozoospermic; OZ), its effects on in vivo sperm motility, and whether there is a correlation with aging. Twenty-eight infertile men (AZ; n = 18 and OZ; n = 10) and 20 fertile normozoospermic (NZ) men were studied. Seminal plasma IGF-I, IGF-II, IGFBP-2, IGFBP-3, and prostate-specific antigen (PSA) levels were measured, and spermatozoa mRNA transcript patterns were examined. Asthenozoospermic men had higher SP IGF-I, IGF-II, IGFBP-2, and PSA levels than NZ and OZ men, whereas SP IGFBP-3 levels were similar between the three groups. Sperm count positively correlated with SP IGF-I, IGF-II, and IGFBP-2; sperm motility negatively correlated with SP IGF-II and IGFBP-2; and age correlated positively with SP IGF-II. The expression of IGF-I and IGF-II mRNA and mRNA receptors was detectable, but no variations in transcript levels were noted. Decreased sperm motility, but not sperm count, in infertile AZ men is associated with increased SP IGF-I, IGF-II, IGFBP-2, and PSA levels. Changes in SP IGFs and their interactions with IGFBPs and IGF receptors, and PSA levels suggest a role of these SP peptides in modulating sperm motility and possibly prostate disease development in aging men.

Imaging and Quantification of mRNA Molecules at Single-Cell Resolution in the Human Fungal Pathogen Candida albicans.

ABSTRACTThe study of gene expression in fungi has typically relied on measuring transcripts in populations of cells. A major disadvantage of this approach is that the transcripts’ spatial distribution and stochastic variation among individual cells within a clonal population is lost. Traditional fluorescence in situ hybridization techniques have been of limited use in fungi due to poor specificity and high background signal. Here, we report that in situ hybridization chain reaction (HCR), a method that employs split-initiator probes to trigger signal amplification upon mRNA-probe hybridization, is ideally suited for the imaging and quantification of low-abundance transcripts at single-cell resolution in the fungus Candida albicans. We show that HCR allows the absolute quantification of transcripts within a cell by microscopy as well as their relative quantification by flow cytometry. mRNA imaging also revealed the subcellular localization of specific transcripts. Furthermore, we establish that HCR is amenable to multiplexing by visualizing different transcripts in the same cell. Finally, we combine HCR with immunostaining to image specific mRNAs and proteins simultaneously within a single C. albicans cell. The fungus is a major pathogen in humans where it can colonize and invade mucosal surfaces and most internal organs. The technical development that we introduce, therefore, paves the way to study the patterns of expression of pathogenesis-associated C. albicans genes in infected organs at single-cell resolution.IMPORTANCE Tools to visualize and quantify transcripts at single-cell resolution have enabled the dissection of spatiotemporal patterns of gene expression in animal cells and tissues. Yet the accurate quantification of transcripts at single-cell resolution remains challenging for the much smaller microbial cells. Widespread phenomena such as stochastic variation in transcript levels among cells—even within a clonal population—seem to play important roles in the biology of many microorganisms. Investigating this process requires microbial cell-optimized procedures to image and measure mRNAs at single-molecule resolution. In this report, we adapt and expand in situ hybridization chain reaction (HCR) combined with split-initiator probes to visualize transcripts in the human-pathogenic fungus Candida albicans at high resolution.

Dose-Dependent Physiological and Transcriptomic Responses of Lettuce (Lactuca sativa L.) to Copper Oxide Nanoparticles-Insights into the Phytotoxicity Mechanisms.

Understanding the complex mechanisms involved in plant response to nanoparticles (NPs) is indispensable in assessing the environmental impact of nano-pollutants. Plant leaves can directly intercept or absorb NPs deposited on their surface; however, the toxicity mechanisms of NPs to plant leaves are unclear. In this study, lettuce leaves were exposed to copper oxide nanoparticles (CuO-NPs, 0, 100, and 1000 mg/L) for 15 days, then physiological tests and transcriptomic analyses were conducted to evaluate the negative impacts of CuO-NPs. Both physiological and transcriptomic results demonstrated that CuO-NPs adversely affected plant growth, photosynthesis, and enhanced reactive oxygen species (ROS) accumulation and antioxidant system activity. The comparative transcriptome analysis showed that 2270 and 4264 genes were differentially expressed upon exposure to 100 and 1000 mg/L CuO-NPs. Gene expression analysis suggested the ATP-binding cassette (ABC) transporter family, heavy metal-associated isoprenylated plant proteins (HIPPs), endocytosis, and other metal ion binding proteins or channels play significant roles in CuO-NP accumulation by plant leaves. Furthermore, the variation in antioxidant enzyme transcript levels (POD1, MDAR4, APX2, FSDs), flavonoid content, cell wall structure and components, and hormone (auxin) could be essential in regulating CuO-NPs-induced stress. These findings could help understand the toxicity mechanisms of metal NPs on crops, especially NPs resulting from foliar exposure.

Deep learning suggests that gene expression is encoded in all parts of a co-evolving interacting gene regulatory structure

Understanding the genetic regulatory code governing gene expression is an important challenge in molecular biology. However, how individual coding and non-coding regions of the gene regulatory structure interact and contribute to mRNA expression levels remains unclear. Here we apply deep learning on over 20,000 mRNA datasets to examine the genetic regulatory code controlling mRNA abundance in 7 model organisms ranging from bacteria to Human. In all organisms, we can predict mRNA abundance directly from DNA sequence, with up to 82% of the variation of transcript levels encoded in the gene regulatory structure. By searching for DNA regulatory motifs across the gene regulatory structure, we discover that motif interactions could explain the whole dynamic range of mRNA levels. Co-evolution across coding and non-coding regions suggests that it is not single motifs or regions, but the entire gene regulatory structure and specific combination of regulatory elements that define gene expression levels.

Base-Pairing Requirements for Small RNA-Mediated Gene Silencing of Recessive Self-Incompatibility Alleles in Arabidopsis halleri.

Small noncoding RNAs are central regulators of genome activity and stability. Their regulatory function typically involves sequence similarity with their target sites, but understanding the criteria by which they specifically recognize and regulate their targets across the genome remains a major challenge in the field, especially in the face of the diversity of silencing pathways involved. The dominance hierarchy among self-incompatibility alleles in Brassicaceae is controlled by interactions between a highly diversified set of small noncoding RNAs produced by dominant S-alleles and their corresponding target sites on recessive S-alleles. By controlled crosses, we created numerous heterozygous combinations of S-alleles in Arabidopsis halleri and developed an real-time quantitative PCR assay to compare allele-specific transcript levels for the pollen determinant of self-incompatibility (SCR). This provides the unique opportunity to evaluate the precise base-pairing requirements for effective transcriptional regulation of this target gene. We found strong transcriptional silencing of recessive SCR alleles in all heterozygote combinations examined. A simple threshold model of base pairing for the small RNA-target interaction captures most of the variation in SCR transcript levels. For a subset of S-alleles, we also measured allele-specific transcript levels of the determinant of pistil specificity (SRK), and found sharply distinct expression dynamics throughout flower development between SCR and SRK In contrast to SCR, both SRK alleles were expressed at similar levels in the heterozygote genotypes examined, suggesting no transcriptional control of dominance for this gene. We discuss the implications for the evolutionary processes associated with the origin and maintenance of the dominance hierarchy among self-incompatibility alleles.

Chronic HCV Infection Is Associated with Overexpression of Human Endogenous Retroviruses that Persists after Drug-Induced Viral Clearance.

Chronic hepatitis C virus (HCV) infection is associated with several hepatic and extrahepatic complications, including cancers and autoimmune disorders, whose frequency is reduced but not abolished after drug-induced viral clearance. The causes of these complications and of their persistence are ill-defined. Human endogenous retroviruses (HERVs) are remnants of ancestral infections and constitute 8% of the human genome. Most HERV elements are inactive, but some are transcribed. HERV overexpression is associated with many cancers and autoimmune diseases with a putative pathogenetic role. Several viral infections trigger HERV activation, but there are no studies on HCV-infected subjects. We assessed, through a PCR real-time amplification assay, the transcription levels of the pol genes of HERV-H, -K, and -W, and of their repressor TRIM28 in white blood cells (WBCs) of vertically infected children, both before and after therapy with direct-acting antivirals (DAAs). The results documented significantly higher expressions of HERV-H-pol and HERV-K-pol, not of HERV-W-pol, in HCV-infected subjects as compared to age-matched controls. HERV RNA levels remained unchanged after DAA-driven viral clearance. No significant variations in transcription levels of TRIM28 were observed in infected subjects. Our findings demonstrate HERV-H-pol and HERV-K-pol overexpression in subjects with chronic HCV infection, without variations after a positive response to DAAs; this might justify their predisposition to cancers and autoimmune disorders that persist after a DAA-induced resolution of viremia.

The Genetics of Differential Gene Expression Related to Fruit Traits in Strawberry (Fragaria ×ananassa).

Octoploid strawberry (Fragaria ×ananassa) is a major specialty crop under intense annual selection for traits relating to plant vigor and fruit quality. Most functional validation experiments rely on transgenic or transient gene expression assays in the mature receptacle. These findings are not typically translatable to breeding without identifying a natural genetic source of transcript level variation, and developing reliable markers for selection in octoploids. Expression QTL (eQTL) analysis is a genetic/transcriptomic association approach for identifying sequence variants predicting differential expression. This eQTL study analyzed a wide array of mature receptacle-expressed genes, encompassing the majority of total mature receptacle transcript accumulation and almost all strawberry genes described in the literature. These results identified segregating genetic variants associated with the differential expression of hundreds of strawberry genes, many with known interest to breeders. Several of these eQTL pertain to published genes whose expression levels have been demonstrated to influence mature receptacle phenotypes. Many include key genes of the phenylpropanoid pathway, vitamin C, carotenoid, pectin, and receptacle carbohydrate/sugar metabolism. These subgenome-specific genetic markers may allow breeders to select for desired ranges of target gene expression. These results may also guide basic research efforts and facilitate the identification of causal genes underlying trait QTL.

1574P - Survival prolongation by rationale innovative genomics (SPRING): An international WIN consortium phase I study exploring safety and efficacy of avelumab, palbociclib, and axitinib in advanced non-small cell lung cancer (NSCLC) with integrated genomic and transcriptomic correlates

1574P - Survival prolongation by rationale innovative genomics (SPRING): An international WIN consortium phase I study exploring safety and efficacy of avelumab, palbociclib, and axitinib in advanced non-small cell lung cancer (NSCLC) with integrated genomic and transcriptomic correlates

Transcriptome analyses of tumor-adjacent somatic tissues reveal genes co-expressed with transposable elements

BackgroundDespite the long-held assumption that transposons are normally only expressed in the germ-line, recent evidence shows that transcripts of transposable element (TE) sequences are frequently found in the somatic cells. However, the extent of variation in TE transcript levels across different tissues and different individuals are unknown, and the co-expression between TEs and host gene mRNAs have not been examined.ResultsHere we report the variation in TE derived transcript levels across tissues and between individuals observed in the non-tumorous tissues collected for The Cancer Genome Atlas. We found core TE co-expression modules consisting mainly of transposons, showing correlated expression across broad classes of TEs. Despite this co-expression within tissues, there are individual TE loci that exhibit tissue-specific expression patterns, when compared across tissues. The core TE modules were negatively correlated with other gene modules that consisted of immune response genes in interferon signaling. KRAB Zinc Finger Proteins (KZFPs) were over-represented gene members of the TE modules, showing positive correlation across multiple tissues. But we did not find overlap between TE-KZFP pairs that are co-expressed and TE-KZFP pairs that are bound in published ChIP-seq studies.ConclusionsWe find unexpected variation in TE derived transcripts, within and across non-tumorous tissues. We describe a broad view of the RNA state for non-tumorous tissues exhibiting higher level of TE transcripts. Tissues with higher level of TE transcripts have a broad range of TEs co-expressed, with high expression of a large number of KZFPs, and lower RNA levels of immune genes.

Transgenerational effects of BPA on female reproduction

Bisphenol A (BPA) is an abundant environmental contaminant and studies have shown the presence of BPA in the urine of over 90% of population tested in Canada and USA. In addition to its reported harmful effects, there is concern for its transgenerational effects. For a compound to induce transgenerational effect, an epigenetic mark should be mitotically and meiotically stable without reprogramming in primordial germ cells and post fertilization embryos. In the present study, female zebrafish were treated with an environmental dose (20 μg/L) of BPA and then crossed with untreated males. To assess epigenetic effects, transcript levels of several genes involved in female reproduction were measured in adult and in 24 hpf embryos up to F3 generation. Exposure to BPA affected adult female fertility up to F2 generation. In F0, F1 and F2 ovaries transcript levels for several genes involved in reproduction, including esr, star, lhcgr and fshr were affected. To investigate epigenetic mechanisms of gene expression modulation, we studied promoter DNA methylation. Among genes involved in gonadal differentiation, amh transcript level was reduced in 24 hpf embryos, up to the F3 generation. Variation in amh transcript level was associated with hyper-methylation of its promoter and changes in H3K4me3/H3K27me3 enrichment, coherent with gene silencing. The findings provide evidence for transgenerational effects of BPA in zebrafish and demonstrate that amh is susceptible to stable epigenetic alterations. CapsuleTransgenerational effects of BPA on female reproductive physiology.