The protein product of the zebrafish homologue of the mouse T gene is expressed in nuclei of the germ ring and the notochord of the early embryo

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 1021-1032 ◽  
Author(s):  
S. Schulte-Merker ◽  
R.K. Ho ◽  
B.G. Herrmann ◽  
C. Nusslein-Volhard
Keyword(s):  
Early Development ◽  
Nuclear Localization ◽  
Protein Product ◽  
Early Embryo ◽  
Paraxial Mesoderm ◽  
Zebrafish Embryos ◽  
Brachydanio Rerio ◽  
Cloning And Sequencing ◽  
Yolk Syncytial Layer ◽  
In Cells

Embryos mutant for the T gene, in mice, make insufficient mesoderm and fail to develop a notochord. We report the cloning and sequencing of the T gene in the zebrafish (Brachydanio rerio) and show the nuclear localization of the protein product. Both RNA and protein are found in cells of the germ ring, including enveloping layer cells, prior to and during gastrulation of zebrafish embryos. Nuclei of the yolk syncytial layer do not express Zf-T. High levels of expression are maintained throughout early development in the notochord, while in paraxial mesoderm cells the gene is turned off during gastrulation. Exposure of animal cap cells to activinA induces Zf-T expression, as does transplantation into the germ ring.

Maternally controlled (beta)-catenin-mediated signaling is required for organizer formation in the zebrafish

Development ◽  
2000 ◽  
Vol 127 (18) ◽  
pp. 3899-3911 ◽  
Author(s):  
C. Kelly ◽  
A.J. Chin ◽  
J.L. Leatherman ◽  
D.J. Kozlowski ◽  
E.S. Weinberg
Keyword(s):  
Early Development ◽  
Nuclear Localization ◽  
Maternal Effect ◽  
Wnt Pathway ◽  
Gene Activity ◽  
Nuclear Accumulation ◽  
Beta Catenin ◽  
Yolk Syncytial Layer ◽  
Embryonic Shield ◽  
Maternal Gene

We have identified and characterized a zebrafish recessive maternal effect mutant, ichabod, that results in severe anterior and dorsal defects during early development. The ichabod mutation is almost completely penetrant, but exhibits variable expressivity. All mutant embryos fail to form a normal embryonic shield; most fail to form a head and notochord and have excessive development of ventral tail fin tissue and blood. Abnormal dorsal patterning can first be observed at 3.5 hpf by the lack of nuclear accumulation of (beta)-catenin in the dorsal yolk syncytial layer, which also fails to express bozozok/dharma/nieuwkoid and znr2/ndr1/squint. At the onset of gastrulation, deficiencies in expression of dorsal markers and expansion of expression of markers of ventral tissues indicate a dramatic alteration of dorsoventral identity. Injection of (beta)-catenin RNA markedly dorsalized ichabod embryos and often completely rescued the phenotype, but no measurable dorsalization was obtained with RNAs encoding upstream Wnt pathway components. In contrast, dorsalization was obtained when RNAs encoding either Bozozok/Dharma/Nieuwkoid or Znr2/Ndr1/Squint were injected. Moreover, injection of (beta)-catenin RNA into ichabod embryos resulted in activation of expression of these two genes, which could also activate each other. RNA injection experiments strongly suggest that the component affected by the ichabod mutation acts on a step affecting (beta)-catenin nuclear localization that is independent of regulation of (beta)-catenin stability. This work demonstrates that a maternal gene controlling localization of (beta)-catenin in dorsal nuclei is necessary for dorsal yolk syncytial layer gene activity and formation of the organizer in the zebrafish.

scholarly journals Signal-mediated localization of Candida albicans pheromone response pathway components

2020 ◽  
Author(s):  
Anna Carolina Borges Pereira Costa ◽  
Raha Parvizi Omran ◽  
Chris Law ◽  
Vanessa Dumeaux ◽  
Malcolm Whiteway
Keyword(s):  
Candida Albicans ◽  
Map Kinase ◽  
Nuclear Localization ◽  
Map Kinases ◽  
Critical Role ◽  
Cell Periphery ◽  
Pheromone Response ◽  
Pheromone Response Pathway ◽  
Localization Signal ◽  
In Cells

Abstract Candida albicans opaque cells release pheromones to stimulate cells of opposite mating type to activate their pheromone response pathway. Although this fungal pathogen shares orthologous proteins involved in the process with Saccharomyces cerevisiae, the pathway in each organism has unique characteristics. We have used GFP-tagged fusion proteins to investigate the localization of the scaffold protein Cst5, as well as the MAP kinases Cek1 and Cek2, during pheromone response in C. albicans. In wild-type cells, pheromone treatment directed Cst5-GFP to surface puncta concentrated at the tips of mating projections. These puncta failed to form in cells defective in either the Gα or β subunits. However, they still formed in response to pheromone in cells missing Ste11, but with the puncta distributed around the cell periphery in the absence of mating projections. These puncta were absent from hst7Δ/Δ cells, but could be detected in the ste11Δ/Δ hst7Δ/Δ double mutant. Cek2-GFP showed a strong nuclear localization late in the response, consistent with a role in adaptation, while Cek1-GFP showed a weaker, but early increase in nuclear localization after pheromone treatment. Activation loop phosphorylation of both Cek1 and Cek2 required the presence of Ste11. In contrast to Cek2-GFP, which showed no localization signal in ste11Δ/Δ cells, Cek1-GFP showed enhanced nuclear localization that was pheromone independent in the ste11Δ/Δ mutant. The results are consistent with CaSte11 facilitating Hst7-mediated MAP kinase phosphorylation and also playing a potentially critical role in both MAP kinase and Cst5 scaffold localization.

scholarly journals Safe-by-Design CuO Nanoparticles via Fe-Doping, Cu–O Bond Length Variation, and Biological Assessment in Cells and Zebrafish Embryos

ACS Nano ◽  
2017 ◽  
Vol 11 (1) ◽  
pp. 501-515 ◽  
Author(s):  
Hendrik Naatz ◽  
Sijie Lin ◽  
Ruibin Li ◽  
Wen Jiang ◽  
Zhaoxia Ji ◽  
...  
Keyword(s):  
Bond Length ◽  
Cuo Nanoparticles ◽  
Biological Assessment ◽  
Zebrafish Embryos ◽  
Length Variation ◽  
Fe Doping ◽  
Safe By Design ◽  
In Cells

The degree of determination of the early embryo of Schistocerca gregaria (Forskål) (Orthoptera: Acrididae)

Development ◽  
1971 ◽  
Vol 25 (3) ◽  
pp. 277-299
Author(s):  
S. K. Moloo
Keyword(s):  
Early Development ◽  
Schistocerca Gregaria ◽  
Early Embryo ◽  
Germ Band ◽  
Early Cleavage ◽  
Band Formation ◽  
Zygote Nucleus ◽  
Young Embryo ◽  
Blastoderm Stage

The degree of determination of the young embryo of S. gregaria has been investigated using ligation, thermocautery and centrifugation techniques. From the overall results, it is suggested that the early development of the embryo is mediated by two physiological centres. The formation of the germ rudiment is controlled by an activation centre located in the periplasm round the posterior end of the egg. This centre is already present at the zygote nucleus stage and is essential during the very early cleavage period. The differentiation of the germ band is induced by the activity of a second centre, the differentiation centre, located in the presumptive thorax. It apparently becomes established at least by the late blastoderm stage and its activity continues during the period of germ-band formation. During the late cleavage and early blastoderm stages, the egg is labile and the embryo is therefore able to normalize its development after part or parts of the germinal Anlage have been cauterized, removed or displaced. The differentiation centre completes its functions by the beginning of gastrulation. Thereafter, the embryo is determined. The embryo can regulate its size at least up to the gastrulation stage provided that a certain minimum amount of usable yolk is available. The development of the serosa is not under the control of either centre. This structure seems to be capable of regeneration providing that a part of the extra-embryonic blastoderm remains intact.

Replication, integration and stable germ-line transmission of foreign sequences injected into early zebrafish embryos

Development ◽  
1988 ◽  
Vol 103 (2) ◽  
pp. 403-412 ◽  
Author(s):  
G.W. Stuart ◽  
J.V. McMurray ◽  
M. Westerfield
Keyword(s):  
Germ Line ◽  
Transmission Rate ◽  
Transgenic Fish ◽  
Early Embryo ◽  
Zebrafish Embryos ◽  
Fish Genome ◽  
Bacterial Plasmid ◽  
Foreign Dna ◽  
High Concentrations ◽  
F2 Progeny

To generate stable lines of transgenic fish, early zebrafish embryos were injected with high concentrations of a linear bacterial plasmid. After injection, the foreign DNA was converted into a high molecular weight form and then amplified approximately tenfold during the initial rapid cleavages characteristic of the early embryo prior to gastrulation. While most of this DNA was subsequently degraded during gastrulation, some of the foreign sequences survived the gastrula stage and could be found in most of the injected fish at 3 weeks of age. Only about 5% of fish analysed 4 months after the injection retained foreign DNA in their fins, usually at less than one copy per cell. One of these fish was also found to contain about 100 copies per cell of foreign DNA in a fraction of its germ cells. Approximately 20% of the F1 offspring from this germ-line-positive parent inherited the foreign DNA, whereas 50% of F2 progeny obtained from an identified F1 individual inherited these sequences. The 50% transmission rate in F2 progeny was as expected for a single, heterozygous genomic insert. These observations indicate that injected DNA can be integrated into the fish genome, that the resulting transgenic fish are mosaic and that some of these mosaic individuals give rise to stable lines of transgenic fish.

A sperm-supplied factor required for embryogenesis in C. elegans

Development ◽  
1996 ◽  
Vol 122 (1) ◽  
pp. 391-404 ◽  
Author(s):  
H. Browning ◽  
S. Strome
Keyword(s):  
Mitotic Spindle ◽  
Early Embryo ◽  
Lethal Gene ◽  
Cloning And Sequencing ◽  
Paternal Effect ◽  
C Elegans ◽  
Essential Function ◽  
The Many ◽  
Embryonic Viability ◽  
Novel Protein

The paternal-effect embryonic-lethal gene, spe-11, is required for normal development of early C. elegans embryos. Spe-11 embryos fail to complete meiosis, form a weak eggshell, fail to orient properly the first mitotic spindle, and fail to undergo cytokinesis. Here we report cloning and sequencing of the spe-11 gene, which encodes a novel protein. As predicted by the paternal-effect mutant phenotype, the gene is expressed during spermatogenesis but is not detectable in females undergoing oogenesis, and the protein is present in mature sperm. To investigate whether SPE-11's essential function is during spermatogenesis or whether sperm-delivered SPE-11 functions in the newly fertilized embryo, we engineered animals to supply SPE-11 to the embryo through the oocyte rather than through the sperm. We found that maternal expression is sufficient for embryonic viability. This result demonstrates that SPE-11 is not required during spermatogenesis, and suggests that SPE-11 is a sperm-supplied factor that participates directly in development of the early embryo. In contrast to the many known maternal factors required for embryogenesis, SPE-11 is the first paternally contributed factor to be genetically identified and molecularly characterized.

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