抄録
Local translation in neuronal dendrites plays a key role in activity-dependent synaptic modifications, and is needed for long-term synaptic plasticity. RNA granules, which consist of clusters of ribosomes and RNAs, are responsible for transport of mRNAs to the dendrites and local translational control. We identified RNG105 (RNA granule protein 105) as a novel component of the RNA granules in dendrites of hippocampal and neocortex neurons. The RNG105-localizing RNA granules contain mRNAs, the translational products of which play key roles in synaptic plasticity. RNG105 is an RNA-binding protein and has ability to repress translation both in vitro and in vivo. Time-laps fluorescence imaging revealed that dissociation of RNG105 from the RNA granules is induced by BDNF (brain-derived neurotrophic factor) stimulation. In contrast, even after the BDNF stimulation, ribosomes remain in/near the RNA granules. The RNG105 dissociation is concomitant with the induction of local translation of the mRNAs located in the RNA granules. These findings suggest that RNG105 is a translational repressor in the RNA granules and becomes dissociated from the granules by synaptic stimulation, which cancels the translational repression of the mRNAs in the RNA granules. We also want to show our recent progress in the study of RNG105 knockout mice and identification of RNG105-associated components of the RNA granules. [J Physiol Sci. 2006;56 Suppl:S58]
