
Wnt/Fz 신호 전달이 파리 유충의 Wave 신경세포의 전후축 방향 축삭 유도를 조절하여 이들 신경세포의 운동 명령을 다양화한다.


coremsg

Functional diversification of homologous neuronal microcircuits is a widespread feature observed across brain regions as well as across species, while its molecular and developmental mechanisms remain largely unknown. We address this question in Drosophila larvae by focusing on segmentally homologous Wave command-like neurons, which diversify their wiring and function in a segment-specific manner. Anterior Wave (a-Wave) neurons extend axons anteriorly and connect to circuits inducing backward locomotion, whereas posterior Wave (p-Wave) neurons extend axons posteriorly and trigger forward locomotion. Here, we show that Frizzled receptors DFz2 and DFz4, together with the DWnt4 ligand, regulate the segment-specific Wave axon projection. DFz2 knock-down (KD) not only reroutes Wave axons to posterior neuromeres but also biases its motor command to induce forward instead of backward locomotion as tactile response. Thus, segment-specific axon guidance diversifies the function of homologous command neurons in behavioral regulation. Since control of anterior-posterior (A-P) axon guidance by Wnt/Fz-signaling is evolutionarily conserved, our results reveal a potentially universal molecular principle for formation and diversification of the command system in the nerve cord. Furthermore, this work indicates that sensorimotor transduction can be rerouted by manipulating a single gene in a single class of neurons, potentially facilitating the evolutionary flexibility in action selection.

Impact statement Rewiring the command neurons in the tactile circuit suffices to change the behavioral strategy of a whole animal, implying a “plug-and-play” flexibility in sensorimotor circuits.

### Competing Interest Statement

The authors have declared no competing interest.

Segment-specific axon guidance by Wnt/Fz signaling diversifies motor commands in Drosophila larvae

파리-유충의-wnt-fz-신호-전달에-의한-분절별-축삭-유도가-운동-명령을-다양화한다


파리 유충의 Wnt/Fz 신호 전달에 의한 분절별 축삭 유도가 운동 명령을 다양화한다


title_rewrite


Drosophila 소형 복측 측면 시계 신경세포의 축삭 투사 방향은 발달 과정에서 변화하며, 이는 Dscam1 수용체와 Netrin 리간드 간의 상호작용에 의해 조절된다.


Axon projection is a spatial and temporal-specific process in which the growth cone receives environmental signals guiding axons to their final destination. However, the mechanisms underlying changes in axonal projection direction without well-defined landmarks remain elusive. Here, we present evidence showcasing the dynamic nature of axonal projections in Drosophila ’s small ventral lateral clock neurons (s-LNvs). Our findings reveal that these axons undergo an initial vertical projection in the early larval stage, followed by a subsequent transition to a horizontal projection in the early-to-mid third instar larvae. The vertical projection of s-LNv axons correlates with mushroom body calyx expansion, while the s-LNv-expressed Down syndrome cell adhesion molecule (Dscam1) interacts with Netrins to regulate the horizontal projection. During a specific temporal window, locally newborn dorsal clock neurons (DNs) secrete Netrins, facilitating the transition of axonal projection direction in s-LNvs. Our study establishes a compelling in vivo model to probe the mechanisms of axonal projection direction switching in the absence of clear landmarks. These findings underscore the significance of dynamic local microenvironments in the complementary regulation of axonal projection direction transitions.

### Competing Interest Statement

The authors have declared no competing interest.

Spatiotemporal Changes in Netrin/Dscam1 Signaling Dictate Axonal Projection Direction in Drosophila Small Ventral Lateral Clock Neurons

drosophila-소형-복측-측면-시계-신경세포의-netrin-dscam1-신호-전달이-축삭-투사-방향을-결정한다


Drosophila 소형 복측 측면 시계 신경세포의 Netrin/Dscam1 신호 전달이 축삭 투사 방향을 결정한다



단일 신경 전구체 수준에서 Sonic Hedgehog 신호에 대한 반응과 세포 운명 결정 사이에 상당한 이질성이 존재한다.


During neural tube patterning, a gradient of Sonic hedgehog (Shh) signaling specifies ventral progenitor fates. The cellular response to Shh is processed through a genetic regulatory network (GRN) to specify distinct fate decisions. This process integrates Shh response level, duration and other inputs and is affected by noise in signaling and cell position. How reliably Shh response profile predicts the fate choice of a single cell is unclear. Here we use live imaging to track neural progenitors in developing zebrafish and quantify both Shh and fate reporters in single cells over time. We found that there is significant heterogeneity between Shh response and fate choice in single cells. We quantitatively modeled reporter intensities to obtain single cell response levels over time and systematically evaluated their correlation with cell fate specification. Motor neuron progenitors (pMN) exhibit a high degree of variability in their Shh responses, which is particularly prominent in the posterior neural tube where the Shh response dynamics are similar to those of the more ventrally fated lateral floor plate cells (LFPs). Our results highlight the precision limit of morphogen-interpretation GRNs in small and dynamic target cell fields.

### Competing Interest Statement

The authors have declared no competing interest.

Heterogeneity of Sonic Hedgehog response dynamics and fate specification in single neural progenitors

단일-신경-전구체에서-관찰된-sonic-hedgehog-반응-동역학과-운명-결정의-이질성


단일 신경 전구체에서 관찰된 Sonic Hedgehog 반응 동역학과 운명 결정의 이질성
