An RNA-interacting protein, SYNCRIP (heterogeneous nuclear ribonuclear protein Q1/NSAP1) is a component of mRNA granule transported with inositol 1,4,5-trisphosphate receptor type 1 mRNA in neuronal dendrites.
mRNA transport and local translation in the neuronal dendrite is implicated in the induction of synaptic plasticity. Recently, we cloned an RNA-interacting protein, SYNCRIP (heterogeneous nuclear ribonuclear protein Q1/NSAP1), that is suggested to be important for the stabilization of mRNA. We report here that SYNCRIP is a component of mRNA granules in rat hippocampal neurons. SYNCRIP was mainly found at cell bodies, but punctate expression patterns in the proximal dendrite were also seen. Time-lapse analysis in living neurons revealed that the granules labeled with fluorescent protein-tagged SYNCRIP were transported bi-directionally within the dendrite at approximately 0.05 microm/s. Treatment of neurons with nocodazole significantly inhibited the movement of green fluorescent protein-SYNCRIP-positive granules, indicating that the transport of SYNCRIP-containing granules is dependent on microtubules. The distribution of SYNCRIP-containing granules overlapped with that of dendritic RNAs and elongation factor 1alpha. SYNCRIP was also found to be co-transported with green fluorescent protein-tagged human staufen1 and the 3'-untranslated region of inositol 1,4,5-trisphosphate receptor type 1 mRNA. These results suggest that SYNCRIP is transported within the dendrite as a component of mRNA granules and raise the possibility that mRNA turnover in mRNA granules and the regulation of local protein synthesis in neuronal dendrites may involve SYNCRIP.
Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Hiroko
H
Bannai
Kazumi
K
Fukatsu
Akihiro
A
Mizutani
Tohru
T
Natsume
Shun-Ichiro
S
Iemura
Tohru
T
Ikegami
Takafumi
T
Inoue
Katsuhiko
K
Mikoshiba
D020413:3' Untranslated Regions; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001692:Biological Transport; D015220:Calcium Channels / Q000737:chemistry*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003712:Dendrites / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D034441:Heterogeneous-Nuclear Ribonucleoproteins / Q000378:metabolism / Q000502:physiology*; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D053496:Inositol 1,4,5-Trisphosphate Receptors; D018613:Microscopy, Confocal; D008870:Microtubules / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D015739:Nocodazole / Q000494:pharmacology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020543:Proteome; D040901:Proteomics / Q000379:methods; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D013997:Time Factors
D020413:3' Untranslated Regions; D000970:Antineoplastic Agents; D015220:Calcium Channels; D034441:Heterogeneous-Nuclear Ribonucleoproteins; C506926:ITPR1 protein, human; D053496:Inositol 1,4,5-Trisphosphate Receptors; D020543:Proteome; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D011993:Recombinant Fusion Proteins; C425312:SYNCRIP protein, human; D049452:Green Fluorescent Proteins; D012313:RNA; D015739:Nocodazole