scholarly journals Albinism as a visual, in vivo guide for CRISPR/Cas9 functionality in the sea urchin embryo

2016 ◽  
Vol 83 (12) ◽  
pp. 1046-1047 ◽  
Author(s):  
Nathalie Oulhen ◽  
Gary M. Wessel
Keyword(s):  
Sea Urchin ◽  
Sea Urchin Embryo

Comparative in vivo evaluation of polyalkoxy substituted 4H-chromenes and oxa-podophyllotoxins as microtubule destabilizing agents in the phenotypic sea urchin embryo assay

2014 ◽  
Vol 24 (16) ◽  
pp. 3914-3918 ◽  
Author(s):  
Marina N. Semenova ◽  
Dmitry V. Tsyganov ◽  
Oleg R. Malyshev ◽  
Oleg V. Ershov ◽  
Ivan N. Bardasov ◽  
...  
Keyword(s):  
Sea Urchin ◽  
In Vivo Evaluation ◽  
Sea Urchin Embryo

Cell-cell interactions regulate skeleton formation in the sea urchin embryo

Development ◽  
1993 ◽  
Vol 119 (3) ◽  
pp. 833-840 ◽  
Author(s):  
N. Armstrong ◽  
J. Hardin ◽  
D.R. McClay
Keyword(s):  
Sea Urchin ◽  
Cell Interactions ◽  
Sea Urchin Embryo ◽  
Skeletal Pattern ◽  
Tissue Sensitivity ◽  
Mesenchyme Cells ◽  
Larval Skeleton ◽  
Skeleton Formation

In the sea urchin embryo, the primary mesenchyme cells (PMCs) make extensive contact with the ectoderm of the blastula wall. This contact is shown to influence production of the larval skeleton by the PMCs. A previous observation showed that treatment of embryos with NiCl2 can alter spicule number and skeletal pattern (Hardin et al. (1992) Development, 116, 671–685). Here, to explore the tissue sensitivity to NiCl2, experiments recombined normal or NiCl2-treated PMCs with either normal or NiCl2-treated PMC-less host embryos. We find that NiCl2 alters skeleton production by influencing the ectoderm of the blastula wall with which the PMCs interact. The ectoderm is responsible for specifying the number of spicules made by the PMCs. In addition, experiments examining skeleton production in vitro and in half- and quarter-sized embryos shows that cell interactions also influence skeleton size. PMCs grown in vitro away from interactions with the rest of the embryo, can produce larger spicules than in vivo. Thus, the epithelium of the blastula wall appears to provide spatial and scalar information that regulates skeleton production by the PMCs.

Spatially regulated SpEts4 transcription factor activity along the sea urchin embryo animal-vegetal axis

Development ◽  
1999 ◽  
Vol 126 (8) ◽  
pp. 1729-1737 ◽  
Author(s):  
Z. Wei ◽  
L.M. Angerer ◽  
R.C. Angerer
Keyword(s):  
Transcription Factor ◽  
Sea Urchin ◽  
Regulatory Region ◽  
High Specificity ◽  
Cis Element ◽  
Sea Urchin Embryo ◽  
Transcriptional Regulatory ◽  
Maternal Transcripts ◽  
Turn Over

Because the transcription of the SpHE gene is regulated cell-autonomously and asymmetrically along the maternally determined animal-vegetal axis of the very early sea urchin embryo, its regulators provide an excellent entry point for investigating the mechanism(s) that establishes this initial polarity. Previous studies support a model in which spatial regulation of SpHE transcription relies on multiple nonvegetal positive transcription factor activities (Wei, Z., Angerer, L. M. and Angerer, R. C. (1997) Dev. Biol. 187, 71–78) and a yeast one-hybrid screen has identified one, SpEts4, which binds with high specificity to a cis element in the SpHE regulatory region and confers positive activation of SpHE promoter transgenes (Wei, Z., Angerer, R. C. and Angerer, L. M. (1999) Mol. Cell. Biol. 19, 1271–1278). Here we demonstrate that SpEts4 can bind to the regulatory region of the endogenous SpHE gene because a dominant repressor, created by fusing SpEts4 DNA binding and Drosophila engrailed repression domains, suppresses its transcription. The pattern of expression of the SpEts4 gene is consistent with a role in regulating SpHE transcription in the nonvegetal region of the embryo during late cleavage/early blastula stages. Although maternal transcripts are uniformly distributed in the egg and early cleaving embryo, they rapidly turn over and are replaced by zygotic transcripts that accumulate in a pattern congruent with SpHE transcription. In addition, in vivo functional tests show that the SpEts4 cis element confers nonvegetal transcription of a beta-galactosidase reporter gene containing the SpHE basal promoter, and provide strong evidence that the activity of this transcription factor is an integral component of the nonvegetal transcriptional regulatory apparatus, which is proximal to, or part of, the mechanism that establishes the animal-vegetal axis of the sea urchin embryo.

The allocation of early blastomeres to the ectoderm and endoderm is variable in the sea urchin embryo

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2213-2223 ◽  
Author(s):  
C.Y. Logan ◽  
D.R. McClay
Keyword(s):  
Sea Urchin ◽  
Low Frequency ◽  
Initial Step ◽  
Cell Types ◽  
Lytechinus Variegatus ◽  
Cell Fates ◽  
Cell Stage ◽  
Sea Urchin Embryo

During sea urchin development, a tier-to-tier progression of cell signaling events is thought to segregate the early blastomeres to five different cell lineages by the 60-cell stage (E. H. Davidson, 1989, Development 105, 421–445). For example, the sixth equatorial cleavage produces two tiers of sister cells called ‘veg1′ and ‘veg2,’ which were projected by early studies to be allocated to the ectoderm and endoderm, respectively. Recent in vitro studies have proposed that the segregation of veg1 and veg2 cells to distinct fates involves signaling between the veg1 and veg2 tiers (O. Khaner and F. Wilt, 1991, Development 112, 881–890). However, fate-mapping studies on 60-cell stage embryos have not been performed with modern lineage tracers, and cell interactions between veg1 and veg2 cells have not been shown in vivo. Therefore, as an initial step towards examining how archenteron precursors are specified, a clonal analysis of veg1 and veg2 cells was performed using the lipophilic dye, DiI(C16), in the sea urchin species, Lytechinus variegatus. Both veg1 and veg2 descendants form archenteron tissues, revealing that the ectoderm and endoderm are not segregated at the sixth cleavage. Also, this division does not demarcate cell type boundaries within the endoderm, because both veg1 and veg2 descendants make an overlapping range of endodermal cell types. The allocation of veg1 cells to ectoderm and endoderm during cleavage is variable, as revealed by both the failure of veg1 descendants labeled at the eighth equatorial division to segregate predictably to either tissue and the large differences in the numbers of veg1 descendants that contribute to the ectoderm. Furthermore, DiI-labeled mesomeres of 32-cell stage embryos also contribute to the endoderm at a low frequency. These results show that the prospective archenteron is produced by a larger population of cleavage-stage blastomeres than believed previously. The segregation of veg1 cells to the ectoderm and endoderm occurs relatively late during development and is unpredictable, indicating that later cell position is more important than the early cleavage pattern in determining ectodermal and archenteron cell fates.

scholarly journals Differential stability of expression of similarly specified endogenous and exogenous genes in the sea urchin embryo

Development ◽  
1991 ◽  
Vol 113 (2) ◽  
pp. 385-398 ◽  
Author(s):  
D.L. Livant ◽  
B.R. Hough-Evans ◽  
J.G. Moore ◽  
R.J. Britten ◽  
E.H. Davidson
Keyword(s):  
Sea Urchin ◽  
Protein Interactions ◽  
Fusion Gene ◽  
Regulatory Sequences ◽  
Mrna Levels ◽  
Dna Fragments ◽  
Exogenous Dna ◽  
Sea Urchin Embryo ◽  
Regulatory Dna

The object of these experiments was to determine whether competitive titration in vivo of factors required for expression of the CyIIIa.CAT fusion gene would affect expression of the endogenous CyIIIa gene in the same embryos. Earlier work showed that expression of this fusion gene after injection into sea urchin eggs is stoichiometrically reduced when low molar excesses of DNA fragments containing only its regulatory domain are coinjected. In order to compare endogenous (i.e. CyIIIa) and exogenous (i.e. CyIIIa.CAT) expression simultaneously in embryos bearing excess competitor regulatory DNA, we developed, and here describe, a new procedure for generating transgenic sea urchin embryos in which all of the cells in many embryos, and most in others, bear the exogenous DNA. Such large reduction of mosaicism can be achieved by multiple injection of the exogenous DNA fragments into fertilized eggs. Using this method, we demonstrate that at a level of competitor DNA incorporation which reduces CyIIIa.CAT expression by 85%, endogenous CyIIIa mRNA levels are wholly unaffected. Nor is spatial expression of the endogenous CyIIIa gene disturbed. Since the CyIIIa.CAT genes are properly expressed under control of the CyIIIa regulatory sequences, they must participate in the same set of necessary DNA-protein interactions. However, we infer from the results that we report here that the regulatory complexes in the endogenous CyIIIa gene are greatly stabilized relative to those of the exogenous CyIIIa.CAT genes.

In vivo Evaluation of Indolyl Glyoxamides in the Phenotypic Sea Urchin Embryo Assay

2007 ◽  
Vol 70 (6) ◽  
pp. 485-490 ◽  
Author(s):  
Marina N. Semenova ◽  
Alex S. Kiselyov ◽  
Ilia Y. Titov ◽  
Mikhail M. Raihstat ◽  
Maxim Molodtsov ◽  
...  
Keyword(s):  
Sea Urchin ◽  
In Vivo Evaluation ◽  
Sea Urchin Embryo

scholarly journals Identification of a New Sea Urchin Ets Protein, SpEts4, by Yeast One-Hybrid Screening with the Hatching Enzyme Promoter

1999 ◽  
Vol 19 (2) ◽  
pp. 1271-1278 ◽  
Author(s):  
Zheng Wei ◽  
Robert C. Angerer ◽  
Lynne M. Angerer
Keyword(s):  
Sea Urchin ◽  
Transcriptional Activation ◽  
Transcriptional Regulator ◽  
Hatching Enzyme ◽  
Nuclear Extracts ◽  
Sea Urchin Embryo ◽  
Ets Family ◽  
High Degree ◽  
Hybrid Screening

ABSTRACT We report the use of a yeast one-hybrid system to isolate a transcriptional regulator of the sea urchin embryo hatching enzyme gene, SpHE. This gene is asymmetrically expressed along the animal-vegetal axis of sea urchin embryos under the cell-autonomous control of maternal regulatory activities and therefore provides an excellent entry point for understanding the mechanism that establishes animal-vegetal developmental polarity. To search for transcriptional regulators, we used a fragment of the SpHE promoter containing several individual elements instead of the conventional bait that contains a multimerized cis element. This screen yielded a number of positive clones that encode a new member of the Ets family, named SpEts4. This protein contains transcriptional activation activity, since expression of reporter genes in yeast does not depend on the presence of the yeast GAL4 activation domain. Sequences in the N-terminal region of SpEts4 mediate the activation activity, as shown by deletion or domain-swapping experiments. The newly identified DNA binding protein binds with a high degree of specificity to aSpHE promoter Ets element and forms a complex with a mobility identical to that obtained with 9-h sea urchin embryo nuclear extracts. SpEts4 positively regulates SpHE transcription, since mutation of the SpEts4 site in SpHE promoter transgenes reduces promoter activity in vivo while SpEts4mRNA coinjection increases its output. As expected for a positiveSpHE transcriptional regulator, the timing ofSpEts4 gene expression precedes the transient expression ofSpHE in the very early sea urchin blastula.

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