scholarly journals Establishment of the Dorsal–Ventral Axis inXenopus Embryos Coincides with the Dorsal Enrichment of Dishevelled That Is Dependent on Cortical Rotation

1999 ◽  
Vol 146 (2) ◽  
pp. 427-438 ◽  
Author(s):  
Jeffrey R. Miller ◽  
Brian A. Rowning ◽  
Carolyn A. Larabell ◽  
Julia A. Yang-Snyder ◽  
Rebecca L. Bates ◽  
...  
Keyword(s):  
Green Fluorescent Protein ◽  
Subcellular Localization ◽  
Uv Irradiation ◽  
Wnt Pathway ◽  
Fluorescent Protein ◽  
Dorsal Side ◽  
Small Vesicle ◽  
Cell Fates ◽  
Vegetal Pole ◽  
Green Fluorescent

Examination of the subcellular localization of Dishevelled (Dsh) in fertilized Xenopus eggs revealed that Dsh is associated with vesicle-like organelles that are enriched on the prospective dorsal side of the embryo after cortical rotation. Dorsal enrichment of Dsh is blocked by UV irradiation of the vegetal pole, a treatment that inhibits development of dorsal cell fates, linking accumulation of Dsh and specification of dorsal cell fates. Investigation of the dynamics of Dsh localization using Dsh tagged with green fluorescent protein (Dsh-GFP) demonstrated that Dsh-GFP associates with small vesicle-like organelles that are directionally transported along the parallel array of microtubules towards the prospective dorsal side of the embryo during cortical rotation. Perturbing the assembly of the microtubule array with D2O, a treatment that promotes the random assembly of the array and the dorsalization of embryos, randomizes translocation of Dsh-GFP. Conversely, UV irradiation of the vegetal pole abolishes movement of Dsh-GFP. Finally, we demonstrate that overexpression of Dsh can stabilize β-catenin in Xenopus. These data suggest that the directional translocation of Dsh along microtubules during cortical rotation and its subsequent enrichment on the prospective dorsal side of the embryo play a role in locally activating a maternal Wnt pathway responsible for establishing dorsal cell fates in Xenopus.

Runt determines cell fates in the Drosophila embryonic CNS

Development ◽  
1998 ◽  
Vol 125 (9) ◽  
pp. 1659-1667 ◽  
Author(s):  
E.L. Dormand ◽  
A.H. Brand
Keyword(s):  
Green Fluorescent Protein ◽  
Fluorescent Protein ◽  
Drosophila Embryo ◽  
Cell Fates ◽  
Segmentation Gene ◽  
Embryonic Cns ◽  
Green Fluorescent

The segmentation gene, runt, is expressed by a subset of the 30 neuroblasts that give rise to each neuromere of the Drosophila embryo. Runt activity in the neuroblasts is necessary for expression of even-skipped in the EL neurons. runt is therefore a good candidate for a gene specifying neuroblast identities. We have ectopically expressed Runt in restricted subsets of neuroblasts and show that Runt is sufficient to activate even-skipped expression in the progeny of specific neuroblasts. Using the marker Tau-green fluorescent protein to highlight the axons, we have found that the extra Even-skipped-expressing neurons project axons along the same pathway as the EL neurons. We find that Runt is expressed in neuroblast 3–3, supporting an autonomous role for runt during neuroblast specification.

scholarly journals Dynamic Changes in Subcellular Localization of Mineralocorticoid Receptor in Living Cells: In Comparison with Glucocorticoid Receptor using Dual-Color Labeling with Green Fluorescent Protein Spectral Variants

2001 ◽  
Vol 15 (7) ◽  
pp. 1077-1092 ◽  
Author(s):  
Mayumi Nishi ◽  
Hiroshi Ogawa ◽  
Takao Ito ◽  
Ken-Ichi Matsuda ◽  
Mitsuhiro Kawata
Keyword(s):  
Green Fluorescent Protein ◽  
Glucocorticoid Receptor ◽  
Subcellular Localization ◽  
Mineralocorticoid Receptor ◽  
Fluorescent Protein ◽  
Living Cells ◽  
Nuclear Accumulation ◽  
Accumulation Rates ◽  
Significant Difference ◽  
Green Fluorescent

Abstract Mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) are ligand-dependent transcription factors. Although it is generally accepted that GR is translocated into the nucleus from the cytoplasm only after ligand binding, the subcellular localization of MR is still quite controversial. We examined the intracellular trafficking of MR in living neurons and nonneural cells using a fusion protein of green fluorescent protein (GFP) and rat MR (GFP-MR). Corticosterone (CORT) induced a rapid nuclear accumulation of GFP-MR, whereas in the absence of ligand, GFP-MR was distributed in both cytoplasm and nucleus in the majority of transfected cells. Given the differential action of MR and GR in the central nervous system, it is important to elucidate how the trafficking of these receptors between cytoplasm and nucleus is regulated by ligand. To examine the simultaneous trafficking of MR and GR within single living cells, we use different spectral variants of GFP, yellow fluorescent protein (YFP) and cyan fluorescent protein (CFP), linked to MR and GR, respectively. In COS-1 cells, expressing no endogenous corticosteroid receptors, the YFP-MR chimera was accumulated in the nucleus faster than the CFP-GR chimera in the presence of 10−9m CORT, while there was no significant difference in the nuclear accumulation rates in the presence of 10−6m CORT. On the other hand, in primary cultured hippocampal neurons expressing endogenous receptors, the nuclear accumulation rates of the YFP-MR chimera and CFP-GR chimera were nearly the same in the presence of both concentrations of CORT. These results suggest that CORT-induced nuclear translocation of MR and GR exhibits differential patterns depending on ligand concentrations or cell types.

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