The unfolded protein response is required for dendrite morphogenesis
- Howard Hughes Medical Institute, Stanford University, United States
- Stanford University School of Medicine, United States
- University of Southern California, United States
- Duke University, United States
Figures
Figure 1 with 3 supplements
ire-1 is required for PVD dendritic morphogenesis.
(A) Cartoon showing the PVD dendritic arbor. The dash-boxed region is magnified to show the PVD soma (asterisk), axon, primary dendrite (1°), secondary dendrite (2°), tertiary dendrite (3°) and …
Figure 1—figure supplement 1
Schematic diagrams of IRE-1 dependent UPR pathway and of C. elegans IRE-1 protein showing three mutations.
(A) Cartoon showing the IRE-1 dependent UPR pathway. Two missense mutations in wy762 and wy782 are shown by asterisks (B) IRE-1 contains a luminal domain (blue), trans-membrane (TM) domain (black …
Figure 1—figure supplement 2
The ire-1 mutants showing PVD dendritic morphogenesis defect.
Representative dendritic morphology of PVD neuron expressing membrane associated GFP (wyIs378) in two ire-1 alleles wy762 (A) and wy782 (B) isolated from forward genetic screen. Asterisks, cell …
Figure 1—figure supplement 3
Compared with wild type animal (A), expressing ire-1 cDNA (B) or spliced xbp-1 cDNA (C) did not cause overbranching of PVD in wild type animals.
Asterisks, cell bodies. Scale bar, 50 μm.
Figure 2 with 3 supplements
The UPR is required for PVD dendritic morphogenesis.
Expressing xbp-1 cDNA in PVD rescues the defective dendritic morphogenesis in ire-1 mutants (A and B) while expressing xbp-1 genomic DNA in PVD does not (C and D). (E and F) Expressing ER chaperone …
Figure 2—figure supplement 1
Dendritic morphogenesis defects of PVD is likely due to lack of specific ER chaperones.
Defective dendritic branching in ire-1 mutants (A) cannot be rescued by overexpressing another ER chaperone HSP-3 (B) or a cytoplasmic chaperone DAF-21 in PVD (C). No detectable PVD branching defect …
Figure 2—figure supplement 2
The RIDD pathway in parallel with XBP-1 to regulate PVD dendritic arbor development.
No PVD dendritic arbor defects are shown in xbp-1 null mutant (B) compared to ire-1 mutant (A) while in xbp-1 background, conditional knockout xrn-1 induced by somatic CRISPR phenocopied the subtle i…
Figure 2—figure supplement 3
Other UPR arms also contribute to dendrite morphogenesis of PVD.
No PVD dendritic arbor defects was shown in atf-6 (A) or pek-1 (B) null mutants while xbp-1 pek-1 double mutant showed ire-1 like phenotype with low-penetrance (C). Asterisks, cell bodies. Scale …
Figure 3 with 2 supplements
DMA-1 is stuck in the somatic ER in ire-1 mutants.
(A) Diagram of PVD in a young adult animal showing three representative subcellular regions: CB (cell body), P (proximal), and D (distal) dendrites. (B to G) Subcellular localization of DMA-1::GFP …
Figure 3—figure supplement 1
DMA-1 is required for PVD dendrite morphogenesis and may be the downstream of HSP-4.
(A) Severe PVD dendritic branching defect in dma-1 mutants. (B) ire-1;dma-1 double mutants show a similar dendritic phenotype to dma-1 single mutants. (C) Overexpression of hsp-4 in ire-1;dma-1 …
Figure 3—figure supplement 2
Subcellular localization of HSP-4::GFP, general ER marker cb5::mCherry and rough ER marker BFP::TRAM in PVD cell body (CB) region (A to C and G to I) and in distal (D) dendritic region (D to F) in wild type animals.
Arrows indicating the general ER marker in PVD distal branches. Scale bar, 5 μm.
Figure 4 with 1 supplement
Overexpressing DMA-1 in ire-1 mutants can either rescue dendritic defects or cause more severe dendrite branching defects.
(A) Representative defective PVD dendritic arbor in ire-1 mutants. (B and C) Overexpressing DMA-1 in PVD in ire-1 mutants rescues the dendritic defect (WT-like) (B) or causes a more severe phenotype …
Figure 4—figure supplement 1
Accumulation or aggregation of DMA-1::GFP in the PVD cell bodies is tightly correlated PVD dendrite morphology.
In the same trangene (wyEx7338) bearing dma-1::GFP expression in ire-1 mutants, there is much less accumulation or aggregation of DMA-1::GFP in the PVD cell bodies with the rescued ‘WT-like’ PVD …
Figure 5 with 1 supplement
The UPR activity is correlated with dendritic branching during development in the PVD neuron.
(A) Design of the PVD-specific UPR activity reporter. The xbp-1 genomic DNA is fused with GFP followed by an SL2::mCherry cassette, which permits the bicistronic expression of XBP-1::GFP and …
Figure 5—figure supplement 1
The UPR activity is correlated with dendritic branching during development in the PVD neuron with another UPR reporter.
The UPR activity is indicated by nuclear HIS-24::GFP brightness (driven by the hsp-4 promoter) while the PVD neuron is labeled and identified by cytoplasmic mCherry. The UPR activity of PVD is shown …
Figure 6 with 3 supplements
The induction of the UPR in PVD depends on the DMA-1.
(A) Diagrams showing two possible models for the activation of the UPR in PVD. (B to J) The PVD UPR activity in WT (B to D), dma-1 mutants (E to G) and WT with overexpession of dma-1 (H to J). Scale …
Figure 6—figure supplement 1
The UPR activity in PVD does not depend on other known proteins that are processed in the ER and are required for PVD dendrite morphogenesis.
The PVD UPR activity in WT (A to C), ire-1 (D to F), hpo-30 (G to I) and kpc-1 mutants (J to L). UPR activity is indicated by XBP-1::GFP brightness while the intensity of mCherry is used to …
Figure 6—figure supplement 2
Another UPR reporter in PVD also showed dramatic decrease in dma-1 mutants.
The UPR activity is indicated by nuclear HIS-24::GFP brightness (regulated by hsp-4 promoter) while the intensity of cytoplasmic mCherry is used to normalize for transgene expression level. The UPR …
Figure 6—figure supplement 3
The UPR in unbranched PVC neurons does not depend on DMA-1.
The UPR activity in WT (A to C) and dma-1 mutants (D to F). UPR activity is measured by XBP-1::GFP brightness while the intensity of mCherry is used to normalize for transgene expression level. …
Figure 7 with 2 supplements
Expression of dma-1 and hsp-4 together in the morphologically simple PDE neurons can induce ectopic branching more dramatically.
(A) Diagram showing the PDE neuron (in red) which is located close to the PVD cell body and has a simple processes running adjacent to the PVD dendrites. Orthogonal ectopic branching (in orange) at …
Figure 7—figure supplement 1
The defective PVD phenotype of ire-1 is suppressed by reduced size of PVD dendritic arbor.
(A). Defective dendritic branch in ire-1 mutants (B). Reduced body length and smaller PVD size in dpy-5 mutants. (C). dpy-5 ire-1 double mutants showing partially rescued PVD morphology. (D). Some dp…
Figure 7—figure supplement 2
Overexpression of dma-1 in PDE induces ectopic branches and increases UPR activity.
Representative morphology of PDE neurons expressing cytoplasmic mCherry in wild-type (A) and a strain with ectopic expression of dma-1 in PDE (D). In these animals, the UPR activity is indicated by P…
Additional files
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Source code 1
Custom built software in Matlab and Python codes. Zip file contains: findPrimary.m to find the PVD primary dendrite, and it calls BDB function (Peng, H, Long, F, Liu, X, Kim, SK, and Myers, EW (2008). Straightening Caenorhabditis elegans images. Bioinformatics 24, 234–242. Cited paper in the manuscript), which is available from http://penglab.janelia.org/proj/wormatlas/bdb_minus_demo_download.html. SplitWorm.m to split the primary dendrite into equal length fragments. PrintSplits.m to draw lines to indicate the segmentation of the primary dendrite. ImageProcessing.py: the python code for image processing and data analysis.
- https://doi.org/10.7554/eLife.06963.025
