Many neurotransmitters and neuromodulators induce gene expression changes in neurons. Transcription factors clearly play a part in this, but chromatin remodelling may also be important. Paolo Sassone-Corsi and colleagues have therefore looked for signs of chromatin remodelling in the transcriptional response of hippocampal neurons to multiple stimuli (see ). Post-transcriptional modifications of conserved residues in the N-terminal tails of histones cause conformational changes in chromatin, which in turn activate or silence genes. When the researchers treated mice systemically with agonists for dopaminergic, acetylcholine or kainate glutamate receptors, histone H3 was rapidly and transiently phosphorylated at Ser10 in different subfields of the hippocampus. Concurrently, the mitogen-activated protein kinase signalling pathway was activated in the same areas and transcription of immediate-early response genes was induced. A causal link between these three events remains to be proven but, say the researchers, the plasticity of chromatin modifications may be an ideal way to facilitate neuronal responses to a range of stimuli.
