[Epigenetics and memory]

Tip60 HAT Action Mediates Environmental Enrichment Induced Cognitive Restoration

Environmental enrichment (EE) conditions have beneficial effects for reinstating cognitive ability in neuropathological disorders like Alzheimer's disease (AD). While EE benefits involve epigenetic gene control mechanisms that comprise histone acetylation, the histone acetyltransferases (HATs) involved remain largely unknown. Here, we examine a role for Tip60 HAT action in mediating activity- dependent beneficial neuroadaptations to EE using the Drosophila CNS mushroom body (MB) as a well-characterized cognition model. We show that flies raised under EE conditions display enhanced MB axonal outgrowth, synaptic marker protein production, histone acetylation induction and transcriptional activation of cognition linked genes when compared to their genotypically identical siblings raised under isolated conditions. Further, these beneficial changes are impaired in both Tip60 HAT mutant flies and APP neurodegenerative flies. While EE conditions provide some beneficial neuroadaptive changes in the APP neurodegenerative fly MB, such positive changes are significantly enhanced by increasing MB Tip60 HAT levels. Our results implicate Tip60 as a critical mediator of EE-induced benefits, and provide broad insights into synergistic behavioral and epigenetic based therapeutic approaches for treatment of cognitive disorder.

[Epigenetic regulation in neuronal differentiation and brain function]

DNA methylation compacts chromatin structure and represses gene transcription. It is important for numerous cellular processes, including embryonic development, X-chromosome inactivation, suppression of transposable elements, and cellular differentiation. In addition, environmental cues, including drugs, pollutants, trauma or early-life social environment, alter DNA methylation patterns in different organs. For instance, studies have unravelled a complex and dynamic interplay between environment, DNA methylation and neuron function during development and in the adult. This crosstalk is hypothesized as an essential molecular event underlying the effects of long-term memory, drug addiction, and several psychotic and behavioural disorders. In this review, we give a summary of this exciting field of research and highlight the molecular functions of DNA methylation and of proteins interacting with methylated DNA.

Reflections on Behavior Analysis and Evolutionary Biology: A Selective Review of Evolution Since Darwin—The First 150 Years. Edited by M. A. Bell, D. J. Futuyama, W. F. Eanes, & J. S. Levinton

This review focuses on parallels between the selectionist sciences of evolutionary biology and behavior analysis. In selectionism, complex phenomena are interpreted as the cumulative products of relatively simple processes acting over time—natural selection in evolutionary biology and reinforcement in behavior analysis. Because evolutionary biology is the more mature science, an examination of the factors that led to the triumph of natural selection provides clues whereby reinforcement may achieve a similar fate in the science of behavior.