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Dynein-dynactin complex is essential for dendritic restriction of TM1-containing Drosophila Dscam.

Yang JS, Bai JM, Lee T - PLoS ONE (2008)

Bottom Line: In contrast, compromising dynein/dynactin function did not affect dendritic targeting of two other dendritic markers, Nod and Rdl.Tracing newly synthesized Dscam[TM1] further revealed that compromising dynein/dynactin function did not affect the initial dendritic targeting of Dscam[TM1], but disrupted the maintenance of its restriction to dendrites.The results of this study suggest multiple mechanisms of dendritic protein targeting.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA.

ABSTRACT

Background: Many membrane proteins, including Drosophila Dscam, are enriched in dendrites or axons within neurons. However, little is known about how the differential distribution is established and maintained.

Methodology/principal findings: Here we investigated the mechanisms underlying the dendritic targeting of Dscam[TM1]. Through forward genetic mosaic screens and by silencing specific genes via targeted RNAi, we found that several genes, encoding various components of the dynein-dynactin complex, are required for restricting Dscam[TM1] to the mushroom body dendrites. In contrast, compromising dynein/dynactin function did not affect dendritic targeting of two other dendritic markers, Nod and Rdl. Tracing newly synthesized Dscam[TM1] further revealed that compromising dynein/dynactin function did not affect the initial dendritic targeting of Dscam[TM1], but disrupted the maintenance of its restriction to dendrites.

Conclusions/significance: The results of this study suggest multiple mechanisms of dendritic protein targeting. Notably, dynein-dynactin plays a role in excluding dendritic Dscam, but not Rdl, from axons by retrograde transport.

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Related in: MedlinePlus

Axonal exclusion of Dscam[TM1], but not Nod or Rdl, requires dynein/dynactin.Larval MB clones co-expressing Dscam[TM1]::GFP (A–D and I–L) with Nod-β-gal (E–H) or Rdl-HA (M–P). As compared to wild-type controls, Lis1, Dmn and p24 mutant clones had Dscam[TM1]::GFP, but not Nod-β-gal or Rdl-HA, mislocalized to the MB axons.
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pone-0003504-g005: Axonal exclusion of Dscam[TM1], but not Nod or Rdl, requires dynein/dynactin.Larval MB clones co-expressing Dscam[TM1]::GFP (A–D and I–L) with Nod-β-gal (E–H) or Rdl-HA (M–P). As compared to wild-type controls, Lis1, Dmn and p24 mutant clones had Dscam[TM1]::GFP, but not Nod-β-gal or Rdl-HA, mislocalized to the MB axons.

Mentions: Nod-β-gal is a fusion protein comprised of the motor domain of Nod and β-galactosidase, and has been shown to be a reliable minus-end reporter for microtubules in Drosophila, including MB neurons [45]–[47]. Consistent with the notion that microtubules are uniformly oriented with plus-end pointing distally in axons, Nod-β-gal was highly enriched in dendrites and cell bodies but largely absent from peduncles and axonal lobes in wild-type MB neurons (Figure 4E and 5E) [30], [43]. Co-expression with dominant-negative Glued or ectopic induction in dynein/dynactin mutant clones (Lis1, Dmn and p24) did not alter its somatodendritic distribution (Figures 4F, 5F, 5G and 5H). These results suggest that dynein/dynactin dysfunction did not perturb microtubule organization in axons, and that mistargeting of Dscam[TM1]::GFP did not occur as a consequence of abnormal microtubule polarity.


Dynein-dynactin complex is essential for dendritic restriction of TM1-containing Drosophila Dscam.

Yang JS, Bai JM, Lee T - PLoS ONE (2008)

Axonal exclusion of Dscam[TM1], but not Nod or Rdl, requires dynein/dynactin.Larval MB clones co-expressing Dscam[TM1]::GFP (A–D and I–L) with Nod-β-gal (E–H) or Rdl-HA (M–P). As compared to wild-type controls, Lis1, Dmn and p24 mutant clones had Dscam[TM1]::GFP, but not Nod-β-gal or Rdl-HA, mislocalized to the MB axons.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2566808&req=5

pone-0003504-g005: Axonal exclusion of Dscam[TM1], but not Nod or Rdl, requires dynein/dynactin.Larval MB clones co-expressing Dscam[TM1]::GFP (A–D and I–L) with Nod-β-gal (E–H) or Rdl-HA (M–P). As compared to wild-type controls, Lis1, Dmn and p24 mutant clones had Dscam[TM1]::GFP, but not Nod-β-gal or Rdl-HA, mislocalized to the MB axons.
Mentions: Nod-β-gal is a fusion protein comprised of the motor domain of Nod and β-galactosidase, and has been shown to be a reliable minus-end reporter for microtubules in Drosophila, including MB neurons [45]–[47]. Consistent with the notion that microtubules are uniformly oriented with plus-end pointing distally in axons, Nod-β-gal was highly enriched in dendrites and cell bodies but largely absent from peduncles and axonal lobes in wild-type MB neurons (Figure 4E and 5E) [30], [43]. Co-expression with dominant-negative Glued or ectopic induction in dynein/dynactin mutant clones (Lis1, Dmn and p24) did not alter its somatodendritic distribution (Figures 4F, 5F, 5G and 5H). These results suggest that dynein/dynactin dysfunction did not perturb microtubule organization in axons, and that mistargeting of Dscam[TM1]::GFP did not occur as a consequence of abnormal microtubule polarity.

Bottom Line: In contrast, compromising dynein/dynactin function did not affect dendritic targeting of two other dendritic markers, Nod and Rdl.Tracing newly synthesized Dscam[TM1] further revealed that compromising dynein/dynactin function did not affect the initial dendritic targeting of Dscam[TM1], but disrupted the maintenance of its restriction to dendrites.The results of this study suggest multiple mechanisms of dendritic protein targeting.

View Article: PubMed Central - PubMed

Affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA.

ABSTRACT

Background: Many membrane proteins, including Drosophila Dscam, are enriched in dendrites or axons within neurons. However, little is known about how the differential distribution is established and maintained.

Methodology/principal findings: Here we investigated the mechanisms underlying the dendritic targeting of Dscam[TM1]. Through forward genetic mosaic screens and by silencing specific genes via targeted RNAi, we found that several genes, encoding various components of the dynein-dynactin complex, are required for restricting Dscam[TM1] to the mushroom body dendrites. In contrast, compromising dynein/dynactin function did not affect dendritic targeting of two other dendritic markers, Nod and Rdl. Tracing newly synthesized Dscam[TM1] further revealed that compromising dynein/dynactin function did not affect the initial dendritic targeting of Dscam[TM1], but disrupted the maintenance of its restriction to dendrites.

Conclusions/significance: The results of this study suggest multiple mechanisms of dendritic protein targeting. Notably, dynein-dynactin plays a role in excluding dendritic Dscam, but not Rdl, from axons by retrograde transport.

Show MeSH
Related in: MedlinePlus