RNA Transport in Dendrites: Acis-Acting Targeting Element Is Contained within Neuronal BC1 RNA

Abstract

In nerve cells, a select group of RNAs has been localized to dendritic domains. Here we have examined dendritic RNA transport in sympathetic neurons in primary culture, using a microinjection protocol with neuronal BC1 RNA and with BC1-derived sequence segments. After cytoplasmic microinjection, full-length BC1 RNA was selectively transported to dendrites; in contrast, control RNAs such as nuclear RNAs and randomsequence irrelevant RNAs remained restricted to cytoplasmic areas proximal to the injection sites. Chimeric RNAs were constructed that contained the full-length BC1 sequence inserted upstream or downstream of the coding regions of nondendritic mRNAs. After microinjection, such chimeric RNAs were specifically targeted to dendrites; microinjected corresponding nonchimeric mRNAs were not. Dendritic transport of BC1 RNA was rapid: the average dendritic delivery rate within the first hour after microinjection was 242 Ϯ 25 m/hr. Whereas a 5Ј-BC1 segment of 62 nucleotides was transported to dendrites to extents and at levels similar to full-length BC1 RNA, a 3Ј-BC1 segment of 60 nucleotides did not exit injected somata to any significant degree. A cis-acting dendritic targeting element is thus contained in the 5Ј part of neuronal BC1 RNA. These results demonstrate that mechanisms exist in neurons for fast and specific transport of selected RNAs to dendrites.

The Brain Cytoplasmic RNA BC1 Regulates Dopamine D2Receptor-Mediated Transmission in the Striatum

“…BC1 is efficiently transported along dendrites and axons and acts as a translational repressor of chimeric mRNAs (Wang et al, 2002). A role for BC1 RNA as a mediator of dendritic mRNA transport (Muslimov et al, 1997) and as a crucial binding partner for the FMRP and other proteins has also been proposed (West et al, 2002;Mallardo et al, 2003;Johnson et al, 2006;Zalfa et al, 2006).…”

Isolation and characterization of Staufen-containing ribonucleoprotein particles from rat brain

“…3B, band b) as BC1, a noncoding RNA transcribed from the RNA polymerase III. Interestingly, BC1 RNA is a component of RNPs in neurons (7,8) and it is not only localized in dendrites in the rodent nervous system, but becomes actively transported into dendrites on cytoplasmic microinjection (31,32). We therefore investigated whether BC1 RNA is also present in our Staufen particles.…”

Dendritic BC200 RNA in aging and in Alzheimer's disease

“…BC RNAs are selectively expressed in neurons and are delivered to synaptodendritic compartments (1,2,(7)(8)(9), where they are thought to contribute to the regulation of local protein synthesis (3,4,6).…”