scholarly journals Global analysis of cell behavior and protein localization dynamics reveals region-specific functions for Shroom3 and N-cadherin during neural tube closure

2021 ◽  
Author(s):  
Austin T. Baldwin ◽  
Juliana Kim ◽  
John B. Wallingford
Keyword(s):  
Neural Tube ◽  
Cell Biology ◽  
Protein Localization ◽  
Global Analysis ◽  
Time Lapse ◽  
Tissue Level ◽  
Neural Tube Closure ◽  
Cell Behaviors ◽  
Regional Specificity ◽  
Tube Closure

AbstractFailures of neural tube closure are common and serious birth defects, yet we have a poor understanding of the interaction of genetics and cell biology during neural tube closure. Additionally, mutations that cause neural tube defects (NTDs) tend to affect anterior or posterior regions of the neural tube but rarely both, indicating a regional specificity to NTD genetics. To better understand the regional specificity of cell behaviors during neural tube closure, we analyzed the dynamic localization of actin and N-cadherin via high-resolution tissue-level time-lapse microscopy during Xenopus neural tube closure. To investigate the regionality of gene function, we generated mosaic mutations in shroom3, a key regulator or neural tube closure This approach elucidates new differences between cell behaviors during cranial/anterior and spinal/posterior neural tube closure, provides mechanistic insight into the function of shroom3 and demonstrates the ability of tissue-level imaging and analysis to generate cell-biological mechanistic insights into neural tube closure.

scholarly journals Live imaging of apoptosis in a novel transgenic mouse highlights its role in neural tube closure

2011 ◽  
Vol 195 (6) ◽  
pp. 1047-1060 ◽  
Author(s):  
Yoshifumi Yamaguchi ◽  
Naomi Shinotsuka ◽  
Keiko Nonomura ◽  
Kiwamu Takemoto ◽  
Keisuke Kuida ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Neural Tube ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Time Lapse ◽  
Neural Tube Closure ◽  
Caspase Activation ◽  
Fluorescent Reporter ◽  
Time Lapse Imaging ◽  
Tube Closure

Many cells die during development, tissue homeostasis, and disease. Dysregulation of apoptosis leads to cranial neural tube closure (NTC) defects like exencephaly, although the mechanism is unclear. Observing cells undergoing apoptosis in a living context could help elucidate their origin, behavior, and influence on surrounding tissues, but few tools are available for this purpose, especially in mammals. In this paper, we used insulator sequences to generate a transgenic mouse that stably expressed a genetically encoded fluorescence resonance energy transfer (FRET)–based fluorescent reporter for caspase activation and performed simultaneous time-lapse imaging of apoptosis and morphogenesis in living embryos. Live FRET imaging with a fast-scanning confocal microscope revealed that cells containing activated caspases showed typical and nontypical apoptotic behavior in a region-specific manner during NTC. Inhibiting caspase activation perturbed and delayed the smooth progression of cranial NTC, which might increase the risk of exencephaly. Our results suggest that caspase-mediated cell removal facilitates NTC completion within a limited developmental window.

scholarly journals Spatial and temporal PCP protein dynamics coordinate cell intercalation during neural tube closure

2018 ◽  
Author(s):  
Mitchell T. Butler ◽  
John B. Wallingford
Keyword(s):  
Neural Tube ◽  
Planar Cell Polarity ◽  
Protein Localization ◽  
Time Lapse ◽  
Neural Tube Closure ◽  
Cell Junctions ◽  
Convergent Extension ◽  
Dynamic Relationships ◽  
Cell Intercalation ◽  
Cell Cell

AbstractPlanar cell polarity (PCP) controls the convergent extension cell movements that drive axis elongation in all vertebrates. Though asymmetric localization of core PCP proteins is central to their function, we currently understand little about PCP protein localization as it relates to the subcellular behaviors that drive convergent extension. Here, we have used high magnification time-lapse imaging to simultaneously monitor cell intercalation behaviors and the localization of the PCP proteins Prickle2 and Vangl2. We observed the expected asymmetric enrichment of PCP proteins, but more interestingly, we also observed tight temporal and spatial correlation of PCP protein enrichment with contractile behavior in cell-cell junctions. These patterns of localization were associated with similar pattern of protein turnover at junctions as assessed by FRAP. In fact, dynamic enrichment of PCP proteins was linked more strongly to junction behavior than to spatial orientation. Finally, recruitment of Prickle2 and Vangl2 to cell-cell junctions was temporally and spatially coordinated with planar polarized oscillations of actomyosin enrichment, and all of these dynamic relationships were disrupted when PCP signaling was manipulated. Together, these results provide a dynamic and quantitative view of PCP protein localization during convergent extension and suggest a complex and intimate link between the dynamic localization of core PCP proteins, actomyosin assembly, and polarized junction shrinking during cell intercalation of the closing vertebrate neural tube.

scholarly journals In vivo time-lapse analysis of cell divisions during neural tube closure

2006 ◽  
Vol 295 (1) ◽  
pp. 444
Author(s):  
Esther K. Kieserman ◽  
Julian M. Tyszka ◽  
John B. Wallingford
Keyword(s):  
Neural Tube ◽  
Time Lapse ◽  
Neural Tube Closure ◽  
Cell Divisions ◽  
Tube Closure

scholarly journals Differential expression and homotypic enrichment of a classic Cadherin directs tissue-level contractile asymmetry during neural tube closure

2018 ◽  
Author(s):  
Hidehiko Hashimoto ◽  
Edwin Munro
Keyword(s):  
Neural Tube ◽  
Rho Gtpase ◽  
Myosin Ii ◽  
Tissue Level ◽  
Neural Tube Closure ◽  
Neural Cells ◽  
Specific Expression ◽  
Rhoa Activity ◽  
Tube Closure ◽  
Do So

SummaryEmbryos pattern force generation at tissue boundaries during morphogenesis, but how they do so remains poorly understood. Here we show how tissue-specific expression of the type II cadherin, Cadherin2 (hereafter Cad2), patterns actomyosin contractility along the neural/epidermal (Ne/Epi) boundary to drive zippering and neural tube closure in the basal chordate, Ciona robusta. Cad2 is differentially expressed and homotypically enriched in neural cells along the Ne/Epi boundary, where RhoA and Myosin are activated during zipper progression. Equalizing Cad2 expression across the Ne/Epi boundary inhibits RhoA/Myosin activation and zipper progression, while creating ectopic Cad2 expression boundaries is sufficient to direct RhoA/Myosin activity to those boundaries. We show that Cad2 polarizes RhoA activity by sequestering the Rho GTPase activating protein, Gap21/23, to homotypic junctions, which in turn redirects RhoA/Myosin activity to heterotypic Ne/Epi junctions. By activating Myosin II along Ne/Epi junctions ahead of zipper and inhibiting Myosin II at new Ne/Ne junctions behind zipper, Cad2 promotes tissue level contractile asymmetry to drive zipper progression.

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