Mining gene expression data for pollutants (dioxin, toluene, formaldehyde) and low dose of gamma-irradiation.

General and specific effects of molecular genetic responses to adverse environmental factors are not well understood. This study examines genome-wide gene expression profiles of Drosophila melanogaster in response to ionizing radiation, formaldehyde, toluene, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. We performed RNA-seq analysis on 25,415 transcripts to measure the change in gene expression in males and females separately. An analysis of the genes unique to each treatment yielded a list of genes as a gene expression signature. In the case of radiation exposure, both sexes exhibited a reproducible increase in their expression of the transcription factors sugarbabe and tramtrack. The influence of dioxin up-regulated metabolic genes, such as anachronism, CG16727, and several genes with unknown function. Toluene activated a gene involved in the response to the toxins, Cyp12d1-p; the transcription factor Fer3's gene; the metabolic genes CG2065, CG30427, and CG34447; and the genes Spn28Da and Spn3, which are responsible for reproduction and immunity. All significantly differentially expressed genes, including those shared among the stressors, can be divided into gene groups using Gene Ontology Biological Process identifiers. These gene groups are related to defense response, biological regulation, the cell cycle, metabolic process, and circadian rhythms. KEGG molecular pathway analysis revealed alteration of the Notch signaling pathway, TGF-beta signaling pathway, proteasome, basal transcription factors, nucleotide excision repair, Jak-STAT signaling pathway, circadian rhythm, Hippo signaling pathway, mTOR signaling pathway, ribosome, mismatch repair, RNA polymerase, mRNA surveillance pathway, Hedgehog signaling pathway, and DNA replication genes. Females and, to a lesser extent, males actively metabolize xenobiotics by the action of cytochrome P450 when under the influence of dioxin and toluene. Finally, in this work we obtained gene expression signatures pollutants (dioxin, toluene), low dose of gamma-irradiation and common molecular pathways for different kind of stressors

The genes selected for expression analysis in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy.

<p>The genes selected for expression analysis in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy.</p

Strehler-Mildvan correlation between the parameters of the Gompertz function in <i>Drosophila melanogaster</i> wild-type <i>Canton-S</i> individuals exposed to low doses of ionizing radiation.

<p>Strehler-Mildvan correlation between the parameters of the Gompertz function in <i>Drosophila melanogaster</i> wild-type <i>Canton-S</i> individuals exposed to low doses of ionizing radiation.</p

The differentially expressed genes in <i>Drosophila melanogaster</i> males and females after the radiation exposure.

<p>A– 5 cGy, B– 10 cGy, C– 20 cGy, D– 40 cGy, 1 –males, 2 –females. Only gene changes with Log₂FC > 1 and p-value < 0.05 during at least one time range are presented.</p

Influence of low doses of γ-irradiation on the lifespan of <i>Drosophila melanogaster</i>, wild-type line <i>Canton-S</i>.

<p>A–males, B–females, *—p<0.05, **—p<0.01, (Kolmogorov-Smirnov test).</p

Effect of Low Doses (5-40 cGy) of Gamma-irradiation on Lifespan and Stress-related Genes Expression Profile in <i>Drosophila melanogaster</i>

<div><p>Studying of the effects of low doses of γ-irradiation is a crucial issue in different areas of interest, from environmental safety and industrial monitoring to aerospace and medicine. The goal of this work is to identify changes of lifespan and expression stress-sensitive genes in <i>Drosophila melanogaster</i>, exposed to low doses of γ-irradiation (5 – 40 cGy) on the imaginal stage of development. Although some changes in life extensity in males were identified (the effect of hormesis after the exposure to 5, 10 and 40 cGy) as well as in females (the effect of hormesis after the exposure to 5 and 40 cGy), they were not caused by the organism “physiological” changes. This means that the observed changes in life expectancy are not related to the changes of organism physiological functions after the exposure to low doses of ionizing radiation. The identified changes in gene expression are not dose-dependent, there is not any proportionality between dose and its impact on expression. These results reflect nonlinear effects of low dose radiation and sex-specific radio-resistance of the postmitotic cell state of <i>Drosophila melanogaster </i>imago.</p></div

Analysis of the gene expression by the qPCR in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy (Female/male).

<p>n–FC absolute value < 2; ǀLog₂FCǀ<1</p><p>+–Log₂FC > 1</p><p>-–Log₂FC < -1</p><p>*—p-value < 0.05</p><p>Analysis of the gene expression by the qPCR in the samples of <i>Drosophila melanogaster</i> wild-type strain <i>Canton-S</i> 72 hours after radiation exposure in doses from 5 cGy to 40 cGy (Female/male).</p

List of unique genes which are up- and down-regulated in both sexes after a particular treatment.

*<p>Gene names were obtained from <a href="http://flybase.org" target="_blank">http://flybase.org</a>.</p>**<p><a href="http://www.uniprot.org" target="_blank">http://www.uniprot.org</a>.</p>***<p>According to Gene Expression Atlas, <a href="http://www.ebi.ac.uk/gxa" target="_blank">http://www.ebi.ac.uk/gxa</a>.</p

Diagrams representing the quantity of shared genes between the different treatments.

<p>Diagrams representing the quantity of shared genes between the different treatments.</p

Principal components biplot on variance stabilized data, color-coded by condition-sex.

<p>PCA scores plot obtained from analysis of gene expression profiles. Proportion of the variance explained is 97.1% for PC1 and 1.1% for PC2.</p