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Genomic DNA that resides in the nuclei of mammalian neurons can be as old as the organism itself. The life span of nuclear RNAs, which are critical for proper chromatin architecture and transcription regulation, has not been determined in adult tissues. In this work, we identified and characterized nuclear RNAs that do not turn over for at least 2 years in a subset of postnatally born cells in the mouse brain. These long-lived RNAs were stably retained in nuclei in a neural cell type-specific manner and were required for the maintenance of heterochromatin. Thus, the life span of neural cells may depend on both the molecular longevity of DNA for the storage of genetic information and also the extreme stability of RNA for the functional organization of chromatin. [ABSTRACT FROM AUTHOR]

Neural stem cells (NSCs) in the hippocampus generate new neurons throughout life, which functionally contribute to cognitive flexibility and mood regulation. Yet adult hippocampal neurogenesis substantially declines with age and age‐related impairments in NSC activity underlie this reduction. Particularly, increased NSC quiescence and consequently reduced NSC proliferation are considered to be major drivers of the low neurogenesis levels in the aged brain. Epigenetic regulators control the gene expression programs underlying NSC quiescence, proliferation and differentiation and are hence critical to the regulation of adult neurogenesis. Epigenetic alterations have also emerged as central hallmarks of aging, and recent studies suggest the deterioration of the NSC‐specific epigenetic landscape as a driver of the age‐dependent decline in adult neurogenesis. In this review, we summarize the recently accumulating evidence for a role of epigenetic dysregulation in NSC aging and propose perspectives for future research directions. [ABSTRACT FROM AUTHOR]

There is still limited mechanistic insight into how the interaction of individuals with their environment results in the emergence of individuality in behavior and brain structure. Nevertheless, the idea that personal activity shapes the brain is implicit in strategies for healthy cognitive aging as well as in the idea that individuality is reflected in the brain's connectome. We have shown that even isogenic mice kept in a shared enriched environment (ENR) developed divergent and stable social and exploratory trajectories. As these trajectories—measured as roaming entropy (RE)—positively correlated with adult hippocampal neurogenesis, we hypothesized that a feedback between behavioral activity and adult hippocampal neurogenesis might be a causal factor in brain individualization. We used cyclin D2 knockout mice with constitutively extremely low levels of adult hippocampal neurogenesis and their wild‐type littermates. We housed them for 3 months in a novel ENR paradigm, consisting of 70 connected cages equipped with radio frequency identification antennae for longitudinal tracking. Cognitive performance was evaluated in the Morris Water Maze task (MWM). With immunohistochemistry we confirmed that adult neurogenesis correlated with RE in both genotypes and that D2 knockout mice had the expected impaired performance in the reversal phase of the MWM. But whereas the wild‐type animals developed stable exploratory trajectories with increasing variance, correlating with adult neurogenesis, this individualizing phenotype was absent in D2 knockout mice. Here the behaviors started out more random and revealed less habituation and low variance. Together, these findings suggest that adult neurogenesis contributes to experience‐dependent brain individualization. [ABSTRACT FROM AUTHOR]

The article offers information on Early-life environmental enrichment which generates persistent individualized behavior in mice. It mentions Using genome-wide DNA methylation sequencing, that show that one-third of the DNA methylation changes were maintained after withdrawal from the enriched environment.

Vibrio coralliilyticus ATCC BAA-450 is a pathogen causing coral bleaching at elevated seawater temperatures. Based on the available genome sequence, the strain has a type III secretion system. Within the corresponding gene cluster, VIC_001052 is encoded, which contains a conserved domain of unknown function DUF1521. In this study, we show that the purified domain exhibits autocleavage activity in the presence of several divalent metal ions, for example, calcium and manganese but not with magnesium or zinc. Autocleavage is not affected by temperatures between 0 and 30 °C, indicating that seawater temperature is not a critical factor for this activity. The DUF1521 domain and the cleavage site are conserved in several proteins from proteobacteria, suggesting a similar cleavage activity for these proteins. [ABSTRACT FROM AUTHOR]

Genetic manipulation of neural precursor cells is an important tool to study mechanisms underlying proliferation, fate specification, and neuron formation. The CRISPR/Cas9 system enables efficient genome editing but requires the clonal expansion of cells containing the desired mutation. Here, we describe a protocol for the effective generation of clonal mouse hippocampal neural precursor lines with CRISPR/Cas9-based gene knockouts. Edited cell lines can be used to investigate gene regulatory networks driving neuronal differentiation and for modeling of diseases that involve hippocampal neurogenesis. For complete details on the use and execution of this protocol, please refer to Pötzsch et al. (2021)., Competing Interests: The authors declare no competing interests., (© 2021 The Author(s).)

One manifestation of individualization is a progressively differential response of individuals to the non-shared components of the same environment. Individualization has practical implications in the clinical setting, where subtle differences between patients are often decisive for the success of an intervention, yet there has been no suitable animal model to study its underlying biological mechanisms. Here we show that enriched environment (ENR) can serve as a model of brain individualization. We kept 40 isogenic female C57BL/6JRj mice for 3 months in ENR and compared these mice to an equally sized group of standard-housed control animals, looking at the effects on a wide range of phenotypes in terms of both means and variances. Although ENR influenced multiple parameters and restructured correlation patterns between them, it only increased differences among individuals in traits related to brain and behavior (adult hippocampal neurogenesis, motor cortex thickness, open field and object exploration), in agreement with the hypothesis of a specific activity-dependent development of brain individuality., Competing Interests: JK, SZ, AG, BM, AP, FE, CS, GK No competing interests declared, (© 2018, Körholz et al.)