Limits...
Spatial codes in dendritic BC1 RNA.

Muslimov IA, Iacoangeli A, Brosius J, Tiedge H - J. Cell Biol. (2006)

Bottom Line: This element features a GA kink-turn (KT) motif that is indispensable for distal targeting.It specifically interacts with heterogeneous nuclear ribonucleoprotein A2, a trans-acting targeting factor that has previously been implicated in the transport of MBP mRNA in oligodendrocytes and neurons.Our work suggests that a BC1 KT motif encodes distal targeting via the A2 pathway and that architectural RNA elements, such as KT motifs, may function as spatial codes in neural cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203, USA.

ABSTRACT
BC1 RNA is a dendritic untranslated RNA that has been implicated in local translational control mechanisms in neurons. Prerequisite for a functional role of the RNA in synaptodendritic domains is its targeted delivery along the dendritic extent. We report here that the targeting-competent 5' BC1 domain carries two dendritic targeting codes. One code, specifying somatic export, is located in the medial-basal region of the 5' BC1 stem-loop structure. It is defined by an export-determinant stem-bulge motif. The second code, specifying long-range dendritic delivery, is located in the apical part of the 5' stem-loop domain. This element features a GA kink-turn (KT) motif that is indispensable for distal targeting. It specifically interacts with heterogeneous nuclear ribonucleoprotein A2, a trans-acting targeting factor that has previously been implicated in the transport of MBP mRNA in oligodendrocytes and neurons. Our work suggests that a BC1 KT motif encodes distal targeting via the A2 pathway and that architectural RNA elements, such as KT motifs, may function as spatial codes in neural cells.

Show MeSH
Dendritic delivery of wild-type BC1 RNA and 5′ BC1 chimeric bcd RNA in sympathetic neurons in culture. (A) Full-length BC1 RNA was transported throughout the entire dendritic extent (Muslimov et al., 1997). The photomicrographs show dark-field (DF; left) and phase-contrast (PC; right) images of injected neurons. BC1 signal appears as white silver grains in DF images. (B) 5′ BC1 chimeric bcd RNA was distally delivered along dendrites, reaching dendritic tips. The 5′ BC1 domain was inserted 5′ of the bcd open reading frame. (C) bcd mRNA remained restricted to neuronal perikarya and was not detectable in proximal dendritic domains. Quantitative data (right) are presented as the mean ± the SEM of relative signal intensities along the dendritic extent. Bar, 50 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC1808587&req=5

fig2: Dendritic delivery of wild-type BC1 RNA and 5′ BC1 chimeric bcd RNA in sympathetic neurons in culture. (A) Full-length BC1 RNA was transported throughout the entire dendritic extent (Muslimov et al., 1997). The photomicrographs show dark-field (DF; left) and phase-contrast (PC; right) images of injected neurons. BC1 signal appears as white silver grains in DF images. (B) 5′ BC1 chimeric bcd RNA was distally delivered along dendrites, reaching dendritic tips. The 5′ BC1 domain was inserted 5′ of the bcd open reading frame. (C) bcd mRNA remained restricted to neuronal perikarya and was not detectable in proximal dendritic domains. Quantitative data (right) are presented as the mean ± the SEM of relative signal intensities along the dendritic extent. Bar, 50 μm.

Mentions: The experimentally established secondary structure of the 5′ BC1 domain (Rozhdestvensky et al., 2001) can be described as an A-form RNA helix with several nonhelical bulge and loop components (Fig. 1). Because RNA functionality is typically expressed by such nonhelical structural motifs (Lilley, 1995; Leontis and Westhof, 2003; Noller, 2005), we decided to examine each of these 5′ BC1 motifs for their contributions to targeting competence. Dendritic transport of the resulting BC1 derivatives was examined using a previously established microinjection protocol with neurons in primary culture (Muslimov et al., 1997; Shan et al., 2003). 35S-labeled RNAs were used throughout because in highly structured RNA motifs fluorescent and other side chains may easily perturb nucleotide–nucleotide or nucleotide–protein interactions that are required for architectural integrity or protein recognition. Dendritic targeting competence was calibrated against wild-type full-length BC1 RNA, which is transported along the entire dendritic extent (Fig. 2 A; Muslimov et al., 1997).


Spatial codes in dendritic BC1 RNA.

Muslimov IA, Iacoangeli A, Brosius J, Tiedge H - J. Cell Biol. (2006)

Dendritic delivery of wild-type BC1 RNA and 5′ BC1 chimeric bcd RNA in sympathetic neurons in culture. (A) Full-length BC1 RNA was transported throughout the entire dendritic extent (Muslimov et al., 1997). The photomicrographs show dark-field (DF; left) and phase-contrast (PC; right) images of injected neurons. BC1 signal appears as white silver grains in DF images. (B) 5′ BC1 chimeric bcd RNA was distally delivered along dendrites, reaching dendritic tips. The 5′ BC1 domain was inserted 5′ of the bcd open reading frame. (C) bcd mRNA remained restricted to neuronal perikarya and was not detectable in proximal dendritic domains. Quantitative data (right) are presented as the mean ± the SEM of relative signal intensities along the dendritic extent. Bar, 50 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1808587&req=5

fig2: Dendritic delivery of wild-type BC1 RNA and 5′ BC1 chimeric bcd RNA in sympathetic neurons in culture. (A) Full-length BC1 RNA was transported throughout the entire dendritic extent (Muslimov et al., 1997). The photomicrographs show dark-field (DF; left) and phase-contrast (PC; right) images of injected neurons. BC1 signal appears as white silver grains in DF images. (B) 5′ BC1 chimeric bcd RNA was distally delivered along dendrites, reaching dendritic tips. The 5′ BC1 domain was inserted 5′ of the bcd open reading frame. (C) bcd mRNA remained restricted to neuronal perikarya and was not detectable in proximal dendritic domains. Quantitative data (right) are presented as the mean ± the SEM of relative signal intensities along the dendritic extent. Bar, 50 μm.
Mentions: The experimentally established secondary structure of the 5′ BC1 domain (Rozhdestvensky et al., 2001) can be described as an A-form RNA helix with several nonhelical bulge and loop components (Fig. 1). Because RNA functionality is typically expressed by such nonhelical structural motifs (Lilley, 1995; Leontis and Westhof, 2003; Noller, 2005), we decided to examine each of these 5′ BC1 motifs for their contributions to targeting competence. Dendritic transport of the resulting BC1 derivatives was examined using a previously established microinjection protocol with neurons in primary culture (Muslimov et al., 1997; Shan et al., 2003). 35S-labeled RNAs were used throughout because in highly structured RNA motifs fluorescent and other side chains may easily perturb nucleotide–nucleotide or nucleotide–protein interactions that are required for architectural integrity or protein recognition. Dendritic targeting competence was calibrated against wild-type full-length BC1 RNA, which is transported along the entire dendritic extent (Fig. 2 A; Muslimov et al., 1997).

Bottom Line: This element features a GA kink-turn (KT) motif that is indispensable for distal targeting.It specifically interacts with heterogeneous nuclear ribonucleoprotein A2, a trans-acting targeting factor that has previously been implicated in the transport of MBP mRNA in oligodendrocytes and neurons.Our work suggests that a BC1 KT motif encodes distal targeting via the A2 pathway and that architectural RNA elements, such as KT motifs, may function as spatial codes in neural cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pharmacology, The Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York Health Science Center at Brooklyn, Brooklyn, NY 11203, USA.

ABSTRACT
BC1 RNA is a dendritic untranslated RNA that has been implicated in local translational control mechanisms in neurons. Prerequisite for a functional role of the RNA in synaptodendritic domains is its targeted delivery along the dendritic extent. We report here that the targeting-competent 5' BC1 domain carries two dendritic targeting codes. One code, specifying somatic export, is located in the medial-basal region of the 5' BC1 stem-loop structure. It is defined by an export-determinant stem-bulge motif. The second code, specifying long-range dendritic delivery, is located in the apical part of the 5' stem-loop domain. This element features a GA kink-turn (KT) motif that is indispensable for distal targeting. It specifically interacts with heterogeneous nuclear ribonucleoprotein A2, a trans-acting targeting factor that has previously been implicated in the transport of MBP mRNA in oligodendrocytes and neurons. Our work suggests that a BC1 KT motif encodes distal targeting via the A2 pathway and that architectural RNA elements, such as KT motifs, may function as spatial codes in neural cells.

Show MeSH