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H2A.Z-Mediated Localization of Genes at the Nuclear Periphery Confers Epigenetic Memory of Previous Transcriptional State

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20.03.2007

Eukaryotic cells control the spatial arrangement of chromosomes; and the localization of genes can both reflect and contribute to their transcriptional state. A number of genes in the simple eukaryote brewer’s yeast are “recruited” to the nuclear periphery through interactions with the nuclear pore complex when they are expressed. The functional significance of peripheral recruitment is unclear.

In this study, Jason Brickner and colleagues show that recruited genes are actively retained at the periphery for generations after transcription is repressed. This suggests that localization at the nuclear periphery represents a novel inherited state that might allow simple eukaryotic organisms to “remember” previous transcriptional activation. This type of memory allows for more robust reactivation of genes, suggesting that it is adaptive. Finally, both retention at the nuclear periphery and rapid reactivation require a variant form of histone H2A.

Adaptive memory is distinct from other types of transcriptional memory. In developmental memory, transcriptional states established by transcriptional regulators early in embryogenesis are propagated long after these regulators have disappeared. Adaptive memory does not propagate a state, but represents a novel state that serves as a source of information. In this way, it resembles a rudimentary form of cellular learning that allows cells to benefit from recent experience.

Andrew Hyde | Source: alphagalileo
Further information: www.plosbiology.org)
biology.plosjournals.org/perlserv/?request=get- document&doi=10.1371/journal.pbio.0050081

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