An injected bacterial effector targets chromatin access for NF-kB as a strategy to shape transcription of immune genes

Phosphorylation of histone H3 at Serine 10 emerges as a mechanism increasing chromatin accessibility of the transcription factor NF-kB for a particular set of immune genes. Here we report that a bacterial pathogen uses this strategy to shape the transcriptional response of infected host cells. We identify the Shigella flexneri type III protein effector OspF as a Dual Specific Phosphatase. OspF dephosphorylates MAP kinases within the nucleus impairing histone H3 phosphorylation at Serine 10 in a gene-specific manner. Therefore, OspF reprograms the transcriptional response for inactivation of a subset of NF-kB responsive genes. This regulation leads to repression of polymorphonuclear leukocytes recruitment in infected tissues. Thus, pathogens have evolved the ability to precisely modulate host cell epigenetic information as a strategy to repress innate immunity.

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Arbibe L, Kim DW, Batsche E, Pedron T, Mateescu B, Muchardt C, Parsot C, Sansonetti PJ