Evidence of functional long-range Wnt/Wg in the developing Drosophila wing epithelium

2018 ◽  
Author(s):  
Varun Chaudhary ◽  
Michael Boutros
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Target Gene ◽  
Secreted Proteins ◽  
Cell Fate Specification ◽  
Wild Type ◽  
Fate Specification ◽  
Drosophila Wing ◽  
Wnt Proteins ◽  
Insight Into

SUMMARYWnts are secreted proteins that regulate cell fate specification during development of all metazoans. Wnt proteins were proposed to spread over several cell diameters to activate signalling directly at a distance. In the Drosophila wing epithelium, an extracellular gradient of Wingless (Wg, the homolog of Wnt1) was observed extending over several cells away from producing cells. However, it was also recently shown that a membrane-tethered Neurotactin-Wg fusion protein (NRT-Wg) can rescue the loss-of endogenous Wg, leading to proper patterning of the wing. Therefore, whether Wg spreading is required for correct tissue patterning during development remains controversial and the functional range of wild-type Wg is unclear. Here, by capturing secreted Wg on distally located cells we show that the Wg gradient acts directly up to eleven cell distances. Cells located outside the reach of extracellular Wg depend on the Frizzled2 receptor to maintain target gene expression. We find that NRT-Wg is not restricted to the producing cells and propose that it can rescue signalling defects by perdurance in the receiving cells. These results provide insight into the mechanisms by which Wnt proteins mediate patterning of a rapidly growing tissue.

scholarly journals Focal adhesion kinase protein regulates Wnt3a gene expression to control cell fate specification in the developing neural plate

2011 ◽  
Vol 22 (13) ◽  
pp. 2409-2421 ◽  
Author(s):  
Yuri Fonar ◽  
Yoni E. Gutkovich ◽  
Heather Root ◽  
Anastasia Malyarova ◽  
Emil Aamar ◽  
...  
Keyword(s):  
Gene Expression ◽  
Wnt Signaling ◽  
Focal Adhesion Kinase ◽  
Cell Fate ◽  
Focal Adhesion ◽  
Control Cell ◽  
Focal Adhesions ◽  
Neural Plate ◽  
Cell Fate Specification ◽  
Fate Specification

Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase protein localized to regions called focal adhesions, which are contact points between cells and the extracellular matrix. FAK protein acts as a scaffold to transfer adhesion-dependent and growth factor signals into the cell. Increased FAK expression is linked to aggressive metastatic and invasive tumors. However, little is known about its normal embryonic function. FAK protein knockdown during early Xenopus laevis development anteriorizes the embryo. Morphant embryos express increased levels of anterior neural markers, with reciprocally reduced posterior neural marker expression. Posterior neural plate folding and convergence-extension is also inhibited. This anteriorized phenotype resembles that of embryos knocked down zygotically for canonical Wnt signaling. FAK and Wnt3a genes are both expressed in the neural plate, and Wnt3a expression is FAK dependent. Ectopic Wnt expression rescues this FAK morphant anteriorized phenotype. Wnt3a thus acts downstream of FAK to balance anterior–posterior cell fate specification in the developing neural plate. Wnt3a gene expression is also FAK dependent in human breast cancer cells, suggesting that this FAK–Wnt linkage is highly conserved. This unique observation connects the FAK- and Wnt-signaling pathways, both of which act to promote cancer when aberrantly activated in mammalian cells.

scholarly journals Transcriptional logic of cell fate specification and axon guidance in early born retinal neurons revealed by single-cell mRNA profiling

2018 ◽  
Author(s):  
Quentin Lo Giudice ◽  
Marion Leleu ◽  
Pierre J. Fabre
Keyword(s):  
Axon Guidance ◽  
Cell Fate ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Retinal Ganglion ◽  
Cell Fate Specification ◽  
Retinal Neurons ◽  
Fate Specification ◽  
Guidance Cues ◽  
Insight Into

ABSTRACTRetinal ganglion cells (RGC), together with cone photoreceptors, horizontal cells (HC) and amacrine cells (AC), are the first classes of neurons produced in the retina. Here we have profiled 5348 single retinal cells and provided a comprehensive transcriptomic atlas showing the broad diversity of the developing retina at the time when the four early-born cells are being produced. Our results show the transcriptional sequences that establish the hierarchical ordering of early cell fate specification in the retina. RGC maturation follows six waves of gene expression, giving new insight into the regulatory logic of RGC differentiation. Early-generated RGCs transcribe an increasing amount of guidance cues for young peripheral RGC axons that express the matching receptors. Finally, spatial signatures in sub-populations of RGCs allowed to define novel molecular markers that are spatially restricted during the development of the retina. Altogether this study is a valuable resource that identifies new players in mouse retinal development, shedding light on transcription factors sequence and guidance cues dynamics in space and time.

scholarly journals Specification of diverse cell types during early neurogenesis of the mouse cerebellum

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
John W Wizeman ◽  
Qiuxia Guo ◽  
Elliott M Wilion ◽  
James YH Li
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Developmental Trajectories ◽  
Ventricular Zone ◽  
Cell Types ◽  
Cell Fate Specification ◽  
Fate Specification ◽  
Integral Role ◽  
Cerebellar Cell ◽  
And Function

We applied single-cell RNA sequencing to profile genome-wide gene expression in about 9400 individual cerebellar cells from the mouse embryo at embryonic day 13.5. Reiterative clustering identified the major cerebellar cell types and subpopulations of different lineages. Through pseudotemporal ordering to reconstruct developmental trajectories, we identified novel transcriptional programs controlling cell fate specification of populations arising from the ventricular zone and the rhombic lip, two distinct germinal zones of the embryonic cerebellum. Together, our data revealed cell-specific markers for studying the cerebellum, gene-expression cascades underlying cell fate specification, and a number of previously unknown subpopulations that may play an integral role in the formation and function of the cerebellum. Our findings will facilitate new discovery by providing insights into the molecular and cell type diversity in the developing cerebellum.

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