scholarly journals Heterogeneous recruitment abilities to RNA polymerases generate nonlinear scaling of gene expression with cell volume

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qirun Wang ◽  
Jie Lin
Keyword(s):  
Gene Expression ◽  
Cell Volume ◽  
Direct Consequence ◽  
Rna Polymerases ◽  
Mrna Levels ◽  
Expression Levels ◽  
Promoter Sequences ◽  
Biophysical Mechanism ◽  
Expression Model ◽  
Cycle Regulation

AbstractWhile most genes’ expression levels are proportional to cell volumes, some genes exhibit nonlinear scaling between their expression levels and cell volume. Therefore, their mRNA and protein concentrations change as the cell volume increases, which often have crucial biological functions such as cell-cycle regulation. However, the biophysical mechanism underlying the nonlinear scaling between gene expression and cell volume is still unclear. In this work, we show that the nonlinear scaling is a direct consequence of the heterogeneous recruitment abilities of promoters to RNA polymerases based on a gene expression model at the whole-cell level. Those genes with weaker (stronger) recruitment abilities than the average ability spontaneously exhibit superlinear (sublinear) scaling with cell volume. Analysis of the promoter sequences and the nonlinear scaling of Saccharomyces cerevisiae’s mRNA levels shows that motifs associated with transcription regulation are indeed enriched in genes exhibiting nonlinear scaling, in concert with our model.

scholarly journals Heterogeneous recruitment abilities to RNA polymerases generate nonlinear scaling of gene expression level with cell volume

2021 ◽  
Author(s):  
Jie Lin
Keyword(s):  
Gene Expression ◽  
Cell Volume ◽  
Direct Consequence ◽  
Rna Polymerases ◽  
Gene Expression Level ◽  
Expression Level ◽  
Expression Levels ◽  
Genes Expression ◽  
Biophysical Mechanism ◽  
Cycle Regulation

Many experiments have shown that most genes’ expression levels are typically proportional to cell volumes in growing cells. However, a finite number of genes often exhibit nonlinear scaling of expression levels with cell volume. Their corresponding mRNA and protein concentrations are therefore not constant as the cell volume increases. While these genes with changing concentrations often have important biological functions such as cell cycle regulation, the biophysical mechanism underlying the nonlinear scaling between the gene expression level and the cell volume is still unclear. In this manuscript, we show that the nonlinear scaling is, in fact, a direct consequence of heterogeneous recruitment abilities of promoters to RNA polymerases. Those genes with weaker (stronger) recruitment abilities compared with the average ability spontaneously exhibit superlinear (sublinear) scaling with cell volume. Our model makes predictions in agreement with experimental observations, including a correlation between the expression levels and nonlinear scaling degrees with cell volume among genes.

scholarly journals Homeostasis of protein and mRNA concentrations in growing cells

2018 ◽  
Author(s):  
Jie Lin ◽  
Ariel Amir
Keyword(s):  
Gene Expression ◽  
Cell Volume ◽  
Linear Growth ◽  
Rna Polymerases ◽  
Transcription Rate ◽  
Translation Rate ◽  
Growing Cell ◽  
Expression Model ◽  
Gene Expression Model ◽  
Per Gene

Many experiments show that the numbers of mRNA and protein are proportional to the cell volume in growing cells. However, models of stochastic gene expression often assume constant transcription rate per gene and constant translation rate per mRNA, which are incompatible with these experiments. Here, we construct a minimal gene expression model to fill this gap. Assuming ribosomes and RNA polymerases are limiting in gene expression, we find that (1) because the ribosomes translate all proteins, the concentrations of proteins and mRNAs are regulated in an exponentially growing cell volume; (2) the competition between genes for the RNA polymerases makes the transcription rate independent of the genome number. Furthermore, by extending the model to situations in which DNA (mRNA) can be saturated by RNA polymerases (ribosomes) and becomes limiting, we predict a transition from exponential to linear growth of cell volume as the protein-to-DNA ratio increases.

scholarly journals Methylobacterium oryzae Influences Isoepoxydon Dehydrogenase Gene Expression and Patulin Production by Penicillium expansum

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1427
Author(s):  
Tiago Barros Afonso ◽  
Lúcia Chaves Simões ◽  
Nelson Lima
Keyword(s):  
Gene Expression ◽  
Distribution Systems ◽  
Water Distribution ◽  
Penicillium Expansum ◽  
Transcriptional Level ◽  
Positive Trend ◽  
Mrna Levels ◽  
Expression Levels ◽  
Production Values ◽  
Methylobacterium Oryzae

Biofilms can be considered the main source of microorganisms in drinking water distribution systems (DWDS). The ecology of a biofilm is dependent on a variety of factors, including the presence of microbial metabolites excreted by its inhabitants. This study reports the effect of the Gram-negative bacteria Methylobacterium oryzae on the idh gene expression levels and patulin production of Penicillium expansum mature biofilms. For this purpose, a RT-qPCR method to quantify idh mRNA levels was applied. In addition, the idh expression levels were compared with the patulin production. The results obtained revealed that the effect of the bacterium on pre-established P. expansum biofilms is dependent on the time of interaction. More mature P. expansum biofilms appear to be more resistant to the inhibitory effect that M. oryzae causes towards idh gene expression and patulin production. A positive trend was observed between the idh expression and patulin production values. The results indicate that M. oryzae affects patulin production by acting at the transcriptional level of the idh gene.

scholarly journals Gene Expression of Nucleic Acid-Sensing Pattern Recognition Receptors in Children Hospitalized for Respiratory Syncytial Virus-Associated Acute Bronchiolitis

2009 ◽  
Vol 16 (6) ◽  
pp. 816-823 ◽  
Author(s):  
Carolina Scagnolari ◽  
Fabio Midulla ◽  
Alessandra Pierangeli ◽  
Corrado Moretti ◽  
Enea Bonci ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pattern Recognition ◽  
Viral Load ◽  
Respiratory Syncytial Virus ◽  
Pattern Recognition Receptors ◽  
Mrna Levels ◽  
Acute Bronchiolitis ◽  
Expression Levels ◽  
Rsv Infection ◽  
Syncytial Virus

ABSTRACT Given the critical role of pattern recognition receptors (PRRs) in acid nucleic recognition in the initiation of innate immunity and the orchestration of adaptive immunity, the aim of this study was to determine whether any heterogeneity of PRR expression in the airway tracts of infants with respiratory syncytial virus (RSV) infection might explain the broad clinical spectrum of RSV-associated bronchiolitis in infants. For this purpose, the levels of melanoma differentiation-associated protein-5 (MDA-5), retinoic acid inducible gene-1 (RIG-1), and Toll-like receptor 3 (TLR-3), TLR-7, TLR-8, and TLR-9 mRNAs were evaluated, using TaqMan quantitative reverse transcription-PCR, in cells from nasopharyngeal washes collected from 157 infants suffering from acute bronchiolitis whether or not they were associated with respiratory viruses. High interindividual variability was observed in both virus-positive and -negative infants; however, the relative gene expression levels of MDA-5, RIG-1, TLR-7, and TLR-8 were significantly higher in the virus-infected group, whereas the expression levels of TLR-3 and TLR-9 were not significantly different. The differences in the gene expression of MDA-5, RIG-1, TLR-7, and TLR-8 were more evident in infants with RSV infection than in those with bocavirus or rhinovirus infection. In RSV-infected infants, PRR-mRNA levels also were analyzed in relation to interferon protein levels, viral load, clinical severity, days of hospitalization, age, and body weight. A significant positive correlation was observed only between RSV viral load and RIG-1 mRNA levels. These findings provide the first direct evidence that, in infants with respiratory virus-associated bronchiolitis, especially RSV, there are substantial changes in PRR gene expression; this likely is an important determinant of the clinical outcome of bronchiolitis.

scholarly journals Codon usage is an important determinant of gene expression levels largely through its effects on transcription

2016 ◽  
Vol 113 (41) ◽  
pp. E6117-E6125 ◽  
Author(s):  
Zhipeng Zhou ◽  
Yunkun Dang ◽  
Mian Zhou ◽  
Lin Li ◽  
Chien-hung Yu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Codon Usage ◽  
Important Determinant ◽  
Mrna Translation ◽  
Mrna Levels ◽  
Protein Coding ◽  
Expression Levels ◽  
Highly Expressed Genes ◽  
The Impact ◽  
Gene Expression Levels

Codon usage biases are found in all eukaryotic and prokaryotic genomes, and preferred codons are more frequently used in highly expressed genes. The effects of codon usage on gene expression were previously thought to be mainly mediated by its impacts on translation. Here, we show that codon usage strongly correlates with both protein and mRNA levels genome-wide in the filamentous fungus Neurospora. Gene codon optimization also results in strong up-regulation of protein and RNA levels, suggesting that codon usage is an important determinant of gene expression. Surprisingly, we found that the impact of codon usage on gene expression results mainly from effects on transcription and is largely independent of mRNA translation and mRNA stability. Furthermore, we show that histone H3 lysine 9 trimethylation is one of the mechanisms responsible for the codon usage-mediated transcriptional silencing of some genes with nonoptimal codons. Together, these results uncovered an unexpected important role of codon usage in ORF sequences in determining transcription levels and suggest that codon biases are an adaptation of protein coding sequences to both transcription and translation machineries. Therefore, synonymous codons not only specify protein sequences and translation dynamics, but also help determine gene expression levels.

ERCC1 and RRM1 but not EGFR gene expression is predictive of shorter survival in advanced non-small cell lung cancer (NSCLC)

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 10030-10030
Author(s):  
G. Selvaggi ◽  
P. Ceppi ◽  
M. Volante ◽  
S. Saviozzi ◽  
S. Novello ◽  
...  
Keyword(s):  
Gene Expression ◽  
Excision Repair ◽  
Growth Factor Receptor ◽  
Needle Aspiration ◽  
Differential Sensitivity ◽  
Mrna Levels ◽  
Female Ratio ◽  
Expression Levels ◽  
Egfr Expression ◽  
Formalin Fixed Paraffin Embedded

10030 Background: Pivotal studies indicate a role of excision repair cross-complementation 1 (ERCC1) and ribonucleotide reductase M1 (RRM1) in conferring a differential sensitivity to cytotoxic chemotherapy and epidermal growth factor receptor (EGFR) has been recently deeply investigated in NSCLC. Methods: We retrospectively collected 70 formalin-fixed paraffin-embedded (FFPE) bronchoscopic/fine needle aspiration biopsies of NSCLC to investigate the expression levels of ERCC1, RRM1 and EGFR by Real-Time PCR (Lord R et al. Clin Cancer Research 2002, 8:2286–91). Results were correlated with survival using the Kaplan-Meier method. Results: Sixty-one (87%) specimens were successfully amplified. Median age was 62 years (range 26–75), male/ female ratio 44/17, stage III/IV 20/41; 43 patients received cisplatin-based chemotherapy; overall median survival (MS) was 13.3 months over a median follow-up time of 45 months. ERCC1 expression level ranged from 0.70 to 15.12, RRM1 0.60–17.82. By adopting cut-off values according to median expression levels, we found a strong correlation between ERCC1 and RRM1 mRNA levels (r=0.410; p<0.001). MS in patients with low ERCC1 was significantly longer (16.9 vs 11.3 months, p<0.006) as well as in patients with low RRM1 (13.9 vs 10.9 months, p<0.03). Concomitant high expression levels of ERCC1 and RRM1 (n=26) are predictive of a worse outcome (13.9 vs 10.9 months, p<0.05). Among patients treated with cisplatin-based regimens, low ERCC1 levels were also predictive of a significantly longer MS (23.0 vs 11.6 months, p<0.002). A lower median ERCC1 level (3.2 vs 4.7) and a correlation with a better outcome were also observed in females vs males. No correlation between gene expression levels and histology was reported. No significant correlation between EGFR expression levels (range 0.5–85.8) and survival was found, even when different cut-off values were tested. Conclusions: This retrospective study further validates ERCC1 and RRM1 as good candidates genes to customize chemotherapy. Prospective studies based on the selection of patients according to genes expression levels are a research priority in early and advanced stages of NSCLC. [Table: see text]

VEGF receptor 1 and heparanase expression as prognostic factors in cholangiocellular carcinoma.

2011 ◽  
Vol 29 (4_suppl) ◽  
pp. 226-226
Author(s):  
E. Goekkurt ◽  
J. Stoehlmacher ◽  
D. E. Aust ◽  
P. V. Danenberg ◽  
K. D. Danenberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Prognostic Factors ◽  
Egf Receptor ◽  
Cholangiocellular Carcinoma ◽  
Vegf Receptor ◽  
Mrna Levels ◽  
Internal Reference ◽  
Logrank Test ◽  
Expression Levels ◽  
Ffpe Tissues

226 Background: Cholangiocellular carcinoma (CCC) remains to be a tumor with very few treatment choices and limited prognosis. In this study, we sought to determine the prognostic role of VEGF receptor 1 (VEGFR1), heparanase (HPSE) and EGF receptor (EGFR) gene expression in patients with resected CCC. Methods: 47 formallin-fixed paraffin embedded FFPE tumor samples from patients with resected CCC were analyzed. FFPE tissues were dissected using laser-captured microdissection and analyzed for VEGFR1, HPSE and EGFR mRNA expression using a quantitative real-time RT-PCR method. Gene expression values (relative mRNA levels) are expressed as ratios between the target gene and internal reference genes (beta-actin, b2mg, rplp2, sdha). Results: VEGFR1 and HPSE expression levels were significantly associated with overall survival (OS). Patients expressing low levels of VEGFR1 displayed a median OS of 23.2 months compared to 5.3 months in patients with high VEGFR1 expression (p=0.006, logrank test). Patients with low HPSE expression had a median OS of 19.8 months compared to 10.0 months in patients with high HPSE expression (p=0.02, logrank test). EGFR and PDGFRα expression were significantly associated with HPSE and VEGFR1 expression (p=0.03 and p<0.0001, respectively). Conclusions: These results suggest that VEGFR1 and HPSE gene expression levels may play a role as prognostic factors in patients with CCC. Further studies are warranted to study these associations. [Table: see text]

Correlation of messenger RNA expression patterns of ERCC1, TS, EGFR, and VEGFR2 with KRAS and BRAF mutational status in advanced colorectal cancer: Implications for targeted therapies.

2013 ◽  
Vol 31 (4_suppl) ◽  
pp. 383-383
Author(s):  
Martin K. H. Maus ◽  
Craig Stephens ◽  
Stephanie H. Astrow ◽  
Peter Philipp Grimminger ◽  
Dongyun Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Mrna Expression ◽  
Advanced Colorectal Cancer ◽  
Expression Patterns ◽  
Mrna Levels ◽  
Expression Levels ◽  
Mutational Status ◽  
Mrna Expression Levels ◽  
Gene Expression Levels

383 Background: Gene expression levels of ERCC1, TS, EGFR and VEGFR2 may have predictive value for the personalized use of standard chemotherapeutics as well as agents targeting the EGFR and VEGF pathways and the efficacy of EGFR directed monoclonal antibodies like panitumumab and cetuximab has been confirmed to be dependent on wt KRAS and wt BRAF in patients with advanced colorectal cancer. We investigated the correlations between KRAS/BRAF mutational status and the mRNA expression levels of these genes. Methods: Formalin-fixed paraffin-embedded tumor specimens from 600 patients with advanced colorectal adenocarcinoma were microdissected and DNA and RNA was extracted. Specifically designed primers and probes were used to detect 7 different base substitutions in codon 12 and 13 of KRAS, V600E mutations in BRAF and the expression levels of ERCC1, TS, EGFR and VEGFR2 by RT-PCR. Results: Mt KRAS tumors had significantly lower TS and EGFR gene expression levels compared with wt KRAS (p<0,001), whereas mt BRAF tumors showed significantly increased TS and EGFR mRNA levels compared to wt BRAF (p<0,001). Mt BRAF tumors showed significantly higher mRNA levels than mt KRAS tumors (p<0,001). ERCC1 and VEGFR2 mRNA levels were significantly down-regulated in mt KRAS specimen (p<0,001), but showed no significant correlation with BRAF mutational status. Conclusions: KRAS and BRAF mutations are associated with opposite mRNA expression levels for TS and EGFR. Recently, resistance to BRAF inhibition in mt BRAF colorectal tumors has been shown in preclinical models to be associated with up-regulation of EGFR. Our data suggests that BRAF mutants are associated with high EGFR levels at the time of diagnosis, and not necessarily part of an acquired mechanism of resistance. Significantly lower mRNA expression levels of VEGFR2 in mt KRAS tumors may explain lower response to angiogenesis inhibition seen in the TML study.

scholarly journals Dynamics Affect Nitrogen Retention, Ileal Amino Acid Digestibility, and Gene Expression Levels of Digestive Enzymes at Three Stages in Pigs Fed Two Levels of Low-Protein Diets

2019 ◽  
Author(s):  
Li Wu ◽  
Qinghua He ◽  
Wen Zhen ◽  
Tiejun Li ◽  
Peng Liao
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
Treatment Group ◽  
Protein Intake ◽  
Digestive Enzymes ◽  
Growing Pigs ◽  
Mrna Levels ◽  
Expression Levels ◽  
Three Stages ◽  
Gene Expression Levels

This study was conducted to determine the dynamic effects of dietary crude protein (CP) intake on nitrogen (N) balance, ileal amino acid digestibility, and gene expression levels of digestive enzymes at three stages in pigs. In Experiment 1, 18 growing pigs (average body weight (BW) = 9.5 kg) were randomly assigned to one of three treatments (n = 6/treatment group), including normal (20% CP), low (17% CP), and very low (14% CP) protein intake. In Experiment 2, 18 growing pigs (average BW = 30 kg) were allotted randomly to one of three treatments (n = 6/treatment group), including normal (18% CP), low (15% CP), and very low (12% CP) protein intake. In Experiment 3, 18 growing pigs (average BW = 45 kg) were assigned randomly to one of three treatments (n = 6/treatment group), including normal (16% CP), low (13% CP), and very low (10% CP) protein intake. Growing pigs fed the 14% CP and 17% CP diets had lower final BW (P &lt; 0.05) and average daily gain (ADG) (P &lt; 0.05) compared to pigs fed the 20% CP diet. Reducing the dietary CP level from 20 to 14% decreased urinary N excretion by 52.8% (P &lt; 0.001) in Experiment 1. Reducing the dietary CP level from 18 to 12% decreased urinary N excretion by 55.3% (P &lt; 0.001) and reduced fecal N excretion by 34% (P &lt; 0.05) in Experiment 2. Reducing the dietary CP level from 16 to 10% decreased urinary N excretion by 56.4% (P &lt; 0.001) and fecal N excretion by 47.1% (P &lt; 0.001) in Experiment 3. Pigs fed the very low (14%, 12%, and 10% CP) diets showed higher digestibility for CP (P &lt; 0.05), His (P &lt; 0.05), Ile (P &lt; 0.05), Phe (P &lt; 0.05), Thr (P &lt; 0.05), Trp (P &lt; 0.05), Glu (P &lt; 0.05), and Ser (P &lt; 0.05) compared to pigs fed the normal (20%, 18%, and 16% CP) diets among the three experiments. Pigs fed the very low (14%, 12%, and 10% CP) diets showed higher mRNA levels for chymotrypsin C (P &lt; 0.01 in Experiment 1 and 2; P &lt; 0.05 in Experiment 3) compared to pigs fed the normal (20%, 18%, and 16% CP) diets among the three experiments. These results indicated that a reduction in dietary CP by 6% limited the growth performance of growing pigs, and a reduction of dietary CP by 3% supplemented with essential amino acids could reduce the excretion of N into the environment without affecting weight gain.

scholarly journals Decreased Levels of Microfibril-Associated Glycoprotein (MAGP)-1 in Patients with Colon Cancer and Obesity Are Associated with Changes in Extracellular Matrix Remodelling

2021 ◽  
Vol 22 (16) ◽  
pp. 8485
Author(s):  
Iranzu Gómez de Segura ◽  
Patricia Ahechu ◽  
Javier Gómez-Ambrosi ◽  
Amaia Rodríguez ◽  
Beatriz Ramírez ◽  
...  
Keyword(s):  
Gene Expression ◽  
Colon Cancer ◽  
Extracellular Matrix ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Mrna Levels ◽  
Expression Levels ◽  
The Impact ◽  
Ht 29 ◽  
Gene Expression Levels

Objective: The protein microfibril-associated glycoprotein (MAGP)-1 constitutes a crucial extracellular matrix protein. We aimed to determine its impact on visceral adipose tissue (VAT) remodelling during obesity-associated colon cancer (CC). Methods: Samples obtained from 79 subjects (29 normoponderal (NP) (17 with CC) and 50 patients with obesity (OB) (19 with CC)) were used in the study. Circulating concentrations of MAGP-1 and its gene expression levels (MFAP2) in VAT were analysed. The impact of inflammation-related factors and adipocyte-conditioned media (ACM) on MFAP2 mRNA levels in colon adenocarcinoma HT-29 cells were further analysed. The effects of MAGP-1 in the expression of genes involved in the extracellular matrix (ECM) remodelling and tumorigenesis in HT-29 cells was also explored. Results: Obesity (p < 0.01) and CC (p < 0.001) significantly decreased MFAP2 gene expression levels in VAT whereas an opposite trend in TGFB1 mRNA levels was observed. Increased mRNA levels of MFAP2 after the stimulation of HT-29 cells with lipopolysaccharide (LPS) (p < 0.01) and interleukin (IL)-4 (p < 0.01) together with a downregulation (p < 0.05) after hypoxia mimicked by CoCl2 treatment was observed. MAGP-1 treatment significantly enhanced the mRNA levels of the ECM-remodelling genes collagen type 6 α3 chain (COL6A3) (p < 0.05), decorin (DCN) (p < 0.01), osteopontin (SPP1) (p < 0.05) and TGFB1 (p < 0.05). Furthermore, MAGP-1 significantly reduced (p < 0.05) the gene expression levels of prostaglandin-endoperoxide synthase 2 (COX2/PTGS2), a key gene controlling cell proliferation, growth and adhesion in CC. Interestingly, a significant decrease (p < 0.01) in the mRNA levels of MFAP2 in HT-29 cells preincubated with ACM from volunteers with obesity compared with control media was observed. Conclusion: The decreased levels of MAGP-1 in patients with obesity and CC together with its capacity to modulate key genes involved in ECM remodelling and tumorigenesis suggest MAGP-1 as a link between AT excess and obesity-associated CC development.

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