Concise Review: Regulatory Influence of Sleep and Epigenetics on Adult Hippocampal Neurogenesis and Cognitive and Emotional Function

Neural stem and progenitor cells continue to generate new neurons in particular regions of the brain during adulthood. One of these neurogenic regions is the dentate gyrus (DG) of the hippocampus, which plays an important role in cognition and emotion. By exploiting this innate neuronal regeneration mechanism in the DG, new technologies have the potential to promote resistance to or recovery from brain dysfunction or degeneration. However, a deeper understanding of how adult DG neurogenesis is regulated by factors such as sleep and epigenetic modifications of gene expression could lead to further breakthroughs in the clinical application of neural stem and progenitor cells. In this review, we discuss the functions of adult‐born DG neurons, describe the epigenetic regulation of adult DG neurogenesis, identify overlaps in how sleep and epigenetic modifications impact adult DG neurogenesis and memory consolidation, and suggest ways of using sleep or epigenetic interventions as therapies for neurodegenerative and psychiatric disorders. By knitting together separate strands of the literature, we hope to trigger new insights into how the functions of adult‐generated neurons are directed by interactions between sleep‐related neural processes and epigenetic mechanisms to facilitate novel approaches to preventing and treating brain disorders such as depression, post‐traumatic stress disorder, and Alzheimer\u27s disease. Stem Cells 2018;36:969–97

A supergene-controlling social structure in Alpine ants also affects the dispersal ability and fecundity of each sex.

Social organization, dispersal and fecundity coevolve, but whether they are genetically linked remains little known. Supergenes are prime candidates for coupling adaptive traits and mediating sex-specific trade-offs. Here, we test whether a supergene that controls social structure in Formica selysi also influences dispersal-related traits and fecundity within each sex. In this ant species, single-queen colonies contain only the ancestral supergene haplotype M and produce MM queens and M males, while multi-queen colonies contain the derived haplotype P and produce MP queens, PP queens and P males. By combining multiple experiments, we show that the M haplotype induces phenotypes with higher dispersal potential and higher fecundity in both sexes. Specifically, MM queens, MP queens and M males are more aerodynamic and more fecund than PP queens and P males, respectively. Differences between MP and PP queens from the same colonies reveal a direct genetic effect of the supergene on dispersal-related traits and fecundity. The derived haplotype P, associated with multi-queen colonies, produces queens and males with reduced dispersal abilities and lower fecundity. More broadly, similarities between the Formica and Solenopsis systems reveal that supergenes play a major role in linking behavioural, morphological and physiological traits associated with intraspecific social polymorphisms

ATF2 is required for amino acid-regulated transcription by orchestrating specific histone acetylation

The transcriptional activation of CHOP (a CCAAT/enhancer-binding protein-related gene) by amino acid deprivation involves the activating transcription factor 2 (ATF2) and the activating transcription factor 4 (ATF4) binding the amino acid response element (AARE) within the promoter. Using a chromatin immunoprecipitation approach, we report that in vivo binding of phospho-ATF2 and ATF4 to CHOP AARE are associated with acetylation of histones H4 and H2B in response to amino acid starvation. A time course analysis reveals that ATF2 phosphorylation precedes histone acetylation, ATF4 binding and the increase in CHOP mRNA. We also show that ATF4 binding and histone acetylation are two independent events that are required for the CHOP induction upon amino acid starvation. Using ATF2-deficient mouse embryonic fibroblasts, we demonstrate that ATF2 is essential in the acetylation of histone H4 and H2B in vivo. The role of ATF2 on histone H4 acetylation is dependent on its binding to the AARE and can be extended to other amino acid regulated genes. Thus, ATF2 is involved in promoting the modification of the chromatin structure to enhance the transcription of a number of amino acid-regulated genes

The p300/CBP-associated factor (PCAF) is a cofactor of ATF4 for amino acid-regulated transcription of CHOP

When an essential amino acid is limited, a signaling cascade is triggered that leads to increased translation of the ‘master regulator’, activating transcription factor 4 (ATF4), and resulting in the induction of specific target genes. Binding of ATF4 to the amino acid response element (AARE) is an essential step in the transcriptional activation of CHOP (a CCAAT/enhancer-binding protein-related gene) by amino acid deprivation. We set out to identify proteins that interact with ATF4 and that play a role in the transcriptional activation of CHOP. Using a tandem affinity purification (TAP) tag approach, we identified p300/CBP-associated factor (PCAF) as a novel interaction partner of ATF4 in leucine-starved cells. We show that the N-terminal region of ATF4 is required for a direct interaction with PCAF and demonstrate that PCAF is involved in the full transcriptional response of CHOP by amino acid starvation. Chromatin immunoprecipitation analysis revealed that PCAF is engaged on the CHOP AARE in response to amino acid starvation and that ATF4 is essential for its recruitment. We also show that PCAF stimulates ATF4-driven transcription via its histone acetyltransferase domain. Thus PCAF acts as a coactivator of ATF4 and is involved in the enhancement of CHOP transcription following amino acid starvation

Milieu de vie quotidien et perception de l'espace : essai sur des quartiers de la banlieue orientale de Lyon

Researches in urban geography have been interested for several years in the study of familiar landscapes perceptions by the inhabitants of the cities. This paper, which is only explorative, deals with large or smaller public houses groups located in the East part of the urban area of Lyon. The analysis of urban space's production and of the numerous talks about it, seems to be a preliminary before any further enquiry. We are convinced that the deep meaning of urban space must be founded from the experience of those who are living in.Depuis plusieurs années des recherches de géographie urbaine s'orientent vers la perception par les habitants de leur milieu de vie quotidien et de leur paysage familier. Notre étude qui n'est qu'exploratrice, a porté sur des ensembles immobiliers isolés et sur une ZUP, dans l'Est de l'agglomération lyonnaise. L'analyse de la production de l'espace urbain et des multiples discours sur lui nous parait un préalable à toute enquête. Nous sommes persuadés que ce n'est qu'en partant de l'expérience de ceux qui le vivent que se révèle la vraie profondeur de l'espace urbain.Chérasse Jean-Claude. Milieu de vie quotidien et perception de l'espace : essai sur des quartiers de la banlieue orientale de Lyon. In: Revue de géographie de Lyon, vol. 56, n°1, 1981. pp. 29-48

Que reste-t-il de la Commune portée par Jules Vallès ?

Que reste-t-il de la Commune de 1871 à l’approche de son 150e anniversaire ? Puisque l’histoire sociale et politique ne saurait être neutre ni impartiale, puisons sans tarder au cœur des luttes actuelles en interviewant l’écrivain Jean Chérasse et le dessinateur Éloi Valat, deux militants passionnés et talentueux, qui aiment convoquer l’éminent communard Jules Vallès tout en œuvrant avec une détermination courageuse à la sauvegarde de la mémoire communeuse.What remains of the Commune of 1871 as it approaches its 150th anniversary ? Since social and political history cannot be neutral or impartial, let’s go straight to the heart of current struggles by interviewing the writer Jean Chérasse and the cartoonist Eloi Valat, two passionate and talented activists who love to summon the eminent communard Jules Vallès while working with courageous determination to safeguard the memory of the Commune

Amino acids as regulators of gene expression in mammals: Molecular mechanisms

Review ArticleInternational audienceIn mammals, the impact of nutrients on gene expression has become an important area of research. Because amino acids have multiple and important functions, their homeostasis has to be finely maintained. However, amino acidemia can be affected in some nutritional conditions and by various forms of stress. Consequently, mammals have to adjust physiological functions involved in the adaptation to amino acid availability. Part of this regulation involves the modulation of numerous gene expression. It has been shown that amino acids by themselves can modify the expression of target genes. This review focuses on the recent advances in the understanding of the mechanisms involved in the control of mammalian gene expression in response to amino acid limitation