Global variability in gene expression and alternative splicing is modulated by mitochondrial content

Noise in gene expression is a main determinant of phenotypic variability. Increasing experimental evidence suggests that genome-wide cellular constraints largely contribute to the heterogeneity observed in gene products. It is still unclear, however, which global factors affect gene expression noise and to what extent. Since eukaryotic gene expression is an energy demanding process, differences in the energy budget of each cell could determine gene expression differences. Here, we quantify the contribution of mitochondrial variability (a natural source of ATP variation) to global variability in gene expression. We find that changes in mitochondrial content can account for ∼50% of the variability observed in protein levels. This is the combined result of the effect of mitochondria dosage on transcription and translation apparatus content and activities. Moreover, we find that mitochondrial levels have a large impact on alternative splicing, thus modulating both the abundance and type of mRNAs. A simple mathematical model in which mitochondrial content simultaneously affects transcription rate and splicing site choice can explain the alternative splicing data. The results of this study show that mitochondrial content (and/or probably function) influences mRNA abundance, translation, and alternative splicing, which ultimately affects cellular phenotypeThe authors would like to thank the Ministerio de Economia y Competitividad (Spain) (Grant numbers BFU2009-10792 and BFU2013-45918-R) and The Medical Research Council (U.K.) for supporting this work. We thank the Fundação Ciência e Tecnologia (Portugal) for funding R.P.N. A.R. held a postgraduate fellowship (FPU) from the Ministerio de Educación y Ciencia. The CBMSO receives an institutional grant from Fundación Ramón Arece

The Pinocchio effect and the Cold Stress Test: Lies and thermography

[EN]We applied the use of thermography to cognitive neuropsychology, particularly as an objective marker of subjective experiences, in the context of lying. We conducted three experiments: (a) An important lie was invented by the participants in 3 min, and it was recounted by phone to a significant person while they were recorded by the thermographic camera, obtaining a face and hands map of the lie. (b) A similar methodology was carried out, but adding the Cold Stress Test (CST) of the dominant hand during the phone call, obtaining a second physiologic marker (the percentage of thermal recovery) to detect the lie. Further, it established a control condition where it generated anxiety in the participants using IAPS images with negative valence and high arousal, which were described by phone to a loved one. We obtained results that showed significant correlations between changes in body temperature and mental set. Of particular interest was the temperature of the nose and hand, which tended to decrease during lying (Experiment 1). The participants also showed a lower recovery of the temperature after the CST when they were lying (Experiment 2). (c) Experi ment 3 is a replication of Experiment 2 but with a different type of lie (a more ecological task) in a different scenario (following the ACID interview, with the use of the phone eliminated and participants motivated to lie well). The main pattern of results was replicated. We obtained an accuracy of 85% in detection of deception with 25% of false alarms.Funding information: CONICYT Chile (FONDECYT 1160368

RESUMEN PAPPS Infancia y Adolescencia 2020

En este documento de actualización presentamos cuatro temas trascendentes para la infancia y la adolescencia en nuestra actividad de atención primaria: el apoyo a la lactancia materna, la promoción de la actividad física, la prevención de lesiones infantiles por accidente de tráfico y el cribado de depresión mayor. Four important topics about children and adolescents in our Primary Care activity are presented in this update document: support for breastfeeding, promotion of physical activity, prevention of child injuries due to traffic accidents, and screening for major depressio

Validating the RedMIT/GFP-LC3 Mouse Model by Studying Mitophagy in Autosomal Dominant Optic Atrophy Due to the OPA1Q285STOP Mutation

Background: Autosomal dominant optic atrophy (ADOA) is usually caused by mutations in the essential gene, OPA1. This encodes a ubiquitous protein involved in mitochondrial dynamics, hence tissue specificity is not understood. Dysregulated mitophagy (mitochondria recycling) is implicated in ADOA, being increased in OPA1 patient fibroblasts. Furthermore, autophagy may be increased in retinal ganglion cells (RGCs) of the OPA1Q285STOPmouse model. Aims: We developed a mouse model for studying mitochondrial dynamics in order to investigate mitophagy in ADOA. Methods: We crossed the OPA1Q285STOPmouse with our RedMIT/GFP-LC3 mouse, harboring red fluorescent mitochondria and green fluorescent autophagosomes. Colocalization between mitochondria and autophagosomes, the hallmark of mitophagy, was quantified in fluorescently labeled organelles in primary cell cultures, using two high throughput imaging methods Imagestream (Amnis) and IN Cell Analyzer 1000 (GE Healthcare Life Sciences). We studied colocalization between mitochondria and autophagosomes in fixed sections using confocal microscopy. Results: We validated our imaging methods for RedMIT/GFP-LC3 mouse cells, showing that colocalization of red fluorescent mitochondria and green fluorescent autophagosomes is a useful indicator of mitophagy. We showed that colocalization increases when lysosomal processing is impaired. Further, colocalization of mitochondrial fragments and autophagosomes is increased in cultures from the OPA1Q285STOP/RedMIT/GFP-LC3 mice compared to RedMIT/GFP-LC3 control mouse cells that were wild type for OPA1. This was apparent in both mouse embryonic fibroblasts (MEFs) using IN Cell 1000 and in splenocytes using ImageStream imaging flow cytometer (Amnis). We confirmed that this represents increased mitophagic flux using lysosomal inhibitors. We also used microscopy to investigate the level of mitophagy in the retina from the OPA1Q285STOP/RedMIT/GFP-LC3 mice and the RedMIT/GFP-LC3 control mice. However, the expression levels of fluorescent proteins and the image signal-to-background ratios precluded the detection of colocalization so we were unable to show any difference in colocalization between these mice. Conclusions: We show that colocalization of fluorescent mitochondria and autophagosomes in cell cultures, but not fixed tissues from the RedMIT/GFP-LC3, can be used to detect mitophagy. We used this model to confirm that mitophagy is increased in a mouse model of ADOA. It will be useful for cell based studies of diseases caused by impaired mitochondrial dynamics

Dynamic protein methylation in chromatin biology

Post-translational modification of chromatin is emerging as an increasingly important regulator of chromosomal processes. In particular, histone lysine and arginine methylation play important roles in regulating transcription, maintaining genomic integrity, and contributing to epigenetic memory. Recently, the use of new approaches to analyse histone methylation, the generation of genetic model systems, and the ability to interrogate genome wide histone modification profiles has aided in defining how histone methylation contributes to these processes. Here we focus on the recent advances in our understanding of the histone methylation system and examine how dynamic histone methylation contributes to normal cellular function in mammals

Stability and stabilization of biocatalysts

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Messenger RNAs that are not synthesized by RNA polymerase II can be 3' end cleaved and polyadenylated.

The poly(A) tail of influenza virus mRNAs is synthesized by the viral RNA polymerase by reiterative copying of a U5-7 sequence near the 5' end of the viral RNA (vRNA) template. We have engineered a vRNA molecule by replacing its viral U6 poly(A) site with a negative-sense eukaryotic polyadenylation signal. The vRNA was transcribed by the viral RNA polymerase and the transcription product was processed by the cellular 3' end processing machinery in vivo. According to the current model, 3' end processing of eukaryotic pre-mRNAs is coupled to cellular RNA polymerase II (pol II) transcription; thus only RNAs synthesized by pol III are believed to be polyadenylated efficiently. Our results show that the cellular polyadenylation machinery is nevertheless able to recognize and process RNA transcripts that are not synthesized by pol II, indicating that synthesis by pol II is not an absolute requirement for 3' end processing in vivo