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Specific microRNAs regulate heat stress responses in Caenorhabditis elegans.

Nehammer C, Podolska A, Mackowiak SD, Kagias K, Pocock R - Sci Rep (2015)

Bottom Line: The ability of animals to sense and respond to elevated temperature is essential for survival.Using in-depth phenotypic analyses of miRNA deletion mutant strains we reveal multiple developmental and post-developmental survival and behavioral functions for specific miRNAs during heat stress.These findings uncover an additional layer of complexity to the regulation of stress signaling that enables animals to robustly respond to the changing environment.

View Article: PubMed Central - PubMed

Affiliation: Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen, Denmark.

ABSTRACT
The ability of animals to sense and respond to elevated temperature is essential for survival. Transcriptional control of the heat stress response has been much studied, whereas its posttranscriptional regulation by microRNAs (miRNAs) is not well understood. Here we analyzed the miRNA response to heat stress in Caenorhabditis elegans and show that a discrete subset of miRNAs is thermoregulated. Using in-depth phenotypic analyses of miRNA deletion mutant strains we reveal multiple developmental and post-developmental survival and behavioral functions for specific miRNAs during heat stress. We have identified additional functions for already known players (mir-71 and mir-239) as well as identifying mir-80 and the mir-229 mir-64-66 cluster as important regulators of the heat stress response in C. elegans. These findings uncover an additional layer of complexity to the regulation of stress signaling that enables animals to robustly respond to the changing environment.

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Egg-Laying Rate and Brood Size are Controlled by miRNAs During Heat Stress.(a–d) Egg-laying proficiency of young adults within a 24-hr period was assayed at the following temperatures: 20°C (a), 28°C (b), 29.5°C (c) and 30°C (d). Data are presented as means ± SEM and statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 10 for 20°C and 28°C, for all other assays n > 28, *p < 0.05, **p < 0.01, ***p < 0.001, n.s - not significant. Experiments were performed in triplicates on three independent days. (e–f) Brood sizes were scored at 20°C and 25°C. Data are presented as means ± SEM. Statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 12, **p < 0.01, ****p < 0.0001 n.s. - not significant. Experiments were performed in triplicates on three independent days.
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f4: Egg-Laying Rate and Brood Size are Controlled by miRNAs During Heat Stress.(a–d) Egg-laying proficiency of young adults within a 24-hr period was assayed at the following temperatures: 20°C (a), 28°C (b), 29.5°C (c) and 30°C (d). Data are presented as means ± SEM and statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 10 for 20°C and 28°C, for all other assays n > 28, *p < 0.05, **p < 0.01, ***p < 0.001, n.s - not significant. Experiments were performed in triplicates on three independent days. (e–f) Brood sizes were scored at 20°C and 25°C. Data are presented as means ± SEM. Statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 12, **p < 0.01, ****p < 0.0001 n.s. - not significant. Experiments were performed in triplicates on three independent days.

Mentions: A previous study found that egg-laying proficiency is sensitive to changes in temperature35. At 28°C, wild type animals robustly lay eggs, whereas at 30°C egg-laying is almost completely abrogated35. We investigated whether TRMs regulate this behavior as we have shown in the present study that these miRNAs are regulated rapidly at the L4 stage of development, which would be an appropriate stage to make such an important behavioral decision. We first tested the ability of TRM mutant adults to lay eggs in a 24-hr period at 20°C and found that loss of mir-229 mir-64-66 caused a slight drop in egg-laying rate (Figure 4A), suggesting a role for these miRNAs in the regulation of egg-laying. At 28°C, all strains exhibited a decrease in the number of eggs laid with mir-80 animals laying significantly fewer eggs than wild type (Figure 4B). As previously published35, at 30°C egg-laying is severely affected where very few eggs are laid by wild type animals in 24 hrs (Figure 4D). We did however observe an additional drop in egg-laying in mir-71 mutant animals and a complete abrogation of egg-laying in mir-80 and mir-239 mutant animals at 30°C. Remarkably, when we performed the same experiment but decreased the incubation temperature by 0.5°C to 29.5°C, wild type animals lay 10-fold more eggs than at 30°C (Figure 4C). In these conditions, mir-71, mir-80 and mir-239 mutant animals still laid significantly fewer eggs than wild type. These experiments show that egg-laying in C. elegans is acutely sensitive to small changes in environmental temperature and that mir-71, mir-80 and mir-239 may regulate this response.


Specific microRNAs regulate heat stress responses in Caenorhabditis elegans.

Nehammer C, Podolska A, Mackowiak SD, Kagias K, Pocock R - Sci Rep (2015)

Egg-Laying Rate and Brood Size are Controlled by miRNAs During Heat Stress.(a–d) Egg-laying proficiency of young adults within a 24-hr period was assayed at the following temperatures: 20°C (a), 28°C (b), 29.5°C (c) and 30°C (d). Data are presented as means ± SEM and statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 10 for 20°C and 28°C, for all other assays n > 28, *p < 0.05, **p < 0.01, ***p < 0.001, n.s - not significant. Experiments were performed in triplicates on three independent days. (e–f) Brood sizes were scored at 20°C and 25°C. Data are presented as means ± SEM. Statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 12, **p < 0.01, ****p < 0.0001 n.s. - not significant. Experiments were performed in triplicates on three independent days.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352874&req=5

f4: Egg-Laying Rate and Brood Size are Controlled by miRNAs During Heat Stress.(a–d) Egg-laying proficiency of young adults within a 24-hr period was assayed at the following temperatures: 20°C (a), 28°C (b), 29.5°C (c) and 30°C (d). Data are presented as means ± SEM and statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 10 for 20°C and 28°C, for all other assays n > 28, *p < 0.05, **p < 0.01, ***p < 0.001, n.s - not significant. Experiments were performed in triplicates on three independent days. (e–f) Brood sizes were scored at 20°C and 25°C. Data are presented as means ± SEM. Statistical significance was assessed by one-way ANOVA analysis followed by Dunnett's multiple comparisons test. n > 12, **p < 0.01, ****p < 0.0001 n.s. - not significant. Experiments were performed in triplicates on three independent days.
Mentions: A previous study found that egg-laying proficiency is sensitive to changes in temperature35. At 28°C, wild type animals robustly lay eggs, whereas at 30°C egg-laying is almost completely abrogated35. We investigated whether TRMs regulate this behavior as we have shown in the present study that these miRNAs are regulated rapidly at the L4 stage of development, which would be an appropriate stage to make such an important behavioral decision. We first tested the ability of TRM mutant adults to lay eggs in a 24-hr period at 20°C and found that loss of mir-229 mir-64-66 caused a slight drop in egg-laying rate (Figure 4A), suggesting a role for these miRNAs in the regulation of egg-laying. At 28°C, all strains exhibited a decrease in the number of eggs laid with mir-80 animals laying significantly fewer eggs than wild type (Figure 4B). As previously published35, at 30°C egg-laying is severely affected where very few eggs are laid by wild type animals in 24 hrs (Figure 4D). We did however observe an additional drop in egg-laying in mir-71 mutant animals and a complete abrogation of egg-laying in mir-80 and mir-239 mutant animals at 30°C. Remarkably, when we performed the same experiment but decreased the incubation temperature by 0.5°C to 29.5°C, wild type animals lay 10-fold more eggs than at 30°C (Figure 4C). In these conditions, mir-71, mir-80 and mir-239 mutant animals still laid significantly fewer eggs than wild type. These experiments show that egg-laying in C. elegans is acutely sensitive to small changes in environmental temperature and that mir-71, mir-80 and mir-239 may regulate this response.

Bottom Line: The ability of animals to sense and respond to elevated temperature is essential for survival.Using in-depth phenotypic analyses of miRNA deletion mutant strains we reveal multiple developmental and post-developmental survival and behavioral functions for specific miRNAs during heat stress.These findings uncover an additional layer of complexity to the regulation of stress signaling that enables animals to robustly respond to the changing environment.

View Article: PubMed Central - PubMed

Affiliation: Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaløes Vej 5, Copenhagen, Denmark.

ABSTRACT
The ability of animals to sense and respond to elevated temperature is essential for survival. Transcriptional control of the heat stress response has been much studied, whereas its posttranscriptional regulation by microRNAs (miRNAs) is not well understood. Here we analyzed the miRNA response to heat stress in Caenorhabditis elegans and show that a discrete subset of miRNAs is thermoregulated. Using in-depth phenotypic analyses of miRNA deletion mutant strains we reveal multiple developmental and post-developmental survival and behavioral functions for specific miRNAs during heat stress. We have identified additional functions for already known players (mir-71 and mir-239) as well as identifying mir-80 and the mir-229 mir-64-66 cluster as important regulators of the heat stress response in C. elegans. These findings uncover an additional layer of complexity to the regulation of stress signaling that enables animals to robustly respond to the changing environment.

Show MeSH
Related in: MedlinePlus