Intracellular mRNA transport and local translation play a key role in neuronal physiology. Translationally repressed mRNAs are transported as a part of ribonucleoprotein (RNP) particles to distant dendritic sites, but the properties of different RNP particles and mechanisms of their repression and transport remain largely unknown. Here, we describe a new class of RNP-particles, the dendritic P-body-like structures (dlPbodies), which are present in the soma and dendrites of mammalian neurons and have both similarities and differences to P-bodies of non-neuronal cells. These structures stain positively for a number of P-body and microRNP components, a microRNA-repressed mRNA and some translational repressors. They appear more heterogeneous than P-bodies of HeLa cells, and they rarely contain the exonuclease Xrn1 but are positive for rRNA. These particles show motorized movements along dendrites and relocalize to distant sites in response to synaptic activation. Furthermore, Dcp1a is stably associated with dlP-bodies in unstimulated cells, but exchanges rapidly on neuronal activation, concomitantly with the loss of Ago2 from dlP-bodies. Thus, dlP-bodies may regulate local translation by storing repressed mRNPs in unstimulated cells, and releasing them on synaptic activation.
Dendrites of mammalian neurons contain specialized P-body-like structures that respond to neuronal activation
Cougot, N.; Bhattacharyya, S. N.; Tapia-Arancibia, L.; Bordonne, R.; Filipowicz, W.; Bertrand, E.; Rage, F.
2008-12-17 / vol 28 / pages 13793-804
28/51/13793 [pii] 10.1523/JNEUROSCI.4155-08.2008
Humans; Animals; Cells, Cultured; Recombinant Fusion Proteins/genetics/metabolism; Rats; Transfection; Hela Cells; MicroRNAs/*metabolism; Biological Transport/physiology; Dendrites/drug effects/*physiology/*ultrastructure; Endoribonucleases/genetics; Eukaryotic Initiation Factor-2/genetics; Excitatory Amino Acid Agonists/pharmacology; Green Fluorescent Proteins/genetics; Hippocampus/cytology; Hypothalamus/cytology; Neurons/drug effects/physiology/*ultrastructure; Particle Size; Ribonucleoproteins/*physiology; RNA, Ribosomal/metabolism; Synaptic Transmission/drug effects/physiology; Trans-Activators/genetics