Mutual inhibition among postmitotic neurons regulates robustness of brain wiring in Drosophila
- VIB, Belgium
- University of Leuven School of Medicine, Belgium
- University of Leuven, Belgium
- Howard Hughes Medical Institute, United States
Figures
Figure 1
Development of the DCN wiring pattern.
The development of the DCN cluster during various time points. At L3 (A, B) the neurites of the DCNs innervate the optic lobe. (A′, A″, B′) During early pupation, DCN axons innervate the lobula and …
Figure 2 with 1 supplement
DCNs are equivalent, their lineage is intrinsically variable and does not predict the wiring pattern.
(A, A′) The cell fate marker atonal is expressed at L3 stage in all DCNs. (B, B′) Acj6, a cell fate marker is expressed in all DCNs at L3 stage. (A, B) Scale bar: 50 µm. (A′, B′) Scale bar: 5 µm. (C)…
Figure 2—figure supplement 1
DCN cell body position highly correlates with its D-V axon position.
First, there is no correlation detectable between the number of neurons within a DCN cluster and the number of medulla axons generated by this cluster (r = 0.3, n = 8). Second, the D-V position of a …
Figure 3 with 2 supplements
Quantitative analysis of the DCN soma and axon.
(A) A typical DCN axonal pattern showing GFP-labeled neurites (green) and LacZ labeled soma (red). Scale bar: 20 µm. (B) Analysis of interaxonal distances of DCN medulla axons along the D-V and A-P …
Figure 3—figure supplement 1
Counting DCN soma and medulla axons.
Technical schematic of the labeling of DCN soma (red) and medulla axons (green) with Cartesian 3D coordinates (yellow dots for DCNs, red dots for medulla axons). DCN: dorsal cluster neurons.
Figure 3—figure supplement 2
Variability of the DCN cluster shape induces robust wiring pattern.
(Result of a DCN density analysis and their medulla axons in two different genetic backgrounds (first row) n = 20 vs (second row) n = 14. First row, typical pattern of the DCNs and their medulla …
Figure 4
Canonical Notch pathway proteins are expressed during axon targeting.
(A–A‴) Expression of Delta (red) and Notch (green) in GFP-labeled DCNs (blue) at ∼32 hr APF. DCNs express both Delta and Notch and the proteins appear intracellular, indicative of active signaling. …
Figure 5 with 5 supplements
Canoncial Notch pathway genes are required postmitotically for axon targeting.
(A, B) A representation of an in vivo DCN cluster with in silico control (A) and in silico reduced Notch activity conditions (B). Red symbolizes cells with low Notch expression level. These cells …
Figure 5—figure supplement 1
Relation between DCN soma distance and the number of adjacent cells within a subcluster
Detailed analysis of distances between DCN soma and theoretical sub-cluster sizes. The number of adjacent cells within the subcluster highly correlates with the Euclidean 3D distance between two DCN …
Figure 5—figure supplement 2
Relation between distances of DCN soma and number of medulla axons.
Using the euclidean 3D distance of 0.17 [nad] the in silico model predicts approximately 12 medulla axons under control conditions. DCN: dorsal cluster neurons.
Figure 5—figure supplement 3
Loss of Delta increase the number of medulla axons.
Delta knockdown via RNAi increases the number of medulla axons. Control 12.33 ± 0.89 SD (n = 12, Gaussian distribution), Delta RNAi 15.29 ± 1.26 (n = 17, Gaussian distribution) (p<0.0001 unpaired …
Figure 5—figure supplement 4
No function of Notch in DCN cell number.
Postmitotic silencing of Notch does not alter DCN cell number. Control 38.13 ± 2 SD (n = 15, non-Gaussian distribution), NotchEC-DN 37.12 ± 3.1 SD (n = 16 Gaussian distributed). There is no …
Figure 5—figure supplement 5
Cell fate marker is expressed in every single neuron at L3.
The cell fate marker atonal top row is expressed under loss of Notch conditions in each neuron at L3 stage as well as the cell fate marker Acj6 (bottom row). Left, scale bar: 50 µm. Right, scale …
Figure 6
Notch signaling attenuates JNK activity via Pak (A–C′) loss of Notch signaling as well as constitutive Pak activation result in clustered axons. Data shown: mean ± SEM. Scale bar: 20 µm. (D) …
Figure 7
Notch acts specifically during the axon sorting phase to regulate DCN axon targeting. (A) Schematic of the axonal dynamics of DCNs during pupal development. (B) Schematic of the temperature shift …
Figure 8 with 3 supplements
Notch cell autonomously regulates axon targeting.
(A–A″) Schematic of a mutual inhibition hypothesis of DCN axon sorting under control and Notch loss of function conditions. (A) Under control conditions only single axons innervate the medulla …
Figure 8—figure supplement 1
Analysis of medulla axons in a genetic MARCM background.
Analysis of number of medulla innervations, using MARCM technique in combination with a background visualization (Cherry). Single control MARCM 13.6 ± 1.12 SD (n = 15, non-Gaussian distribution), …
Figure 8—figure supplement 2
Loss of Notch function does not alter the D-V position.
An adult fly brain showing the entire DCN pattern marked with Cherry and a single GFP-positive NDNDCN clone with its neurites, generated using MARCM. The D-V position of the DCN soma and its …
Figure 8—figure supplement 3
Multi-cell loss of N clone provides clustered axons.
An additional example for multi-cell NDNDCN clone with clustered (GFP-positive) medulla axons.
