Regulating potential in development of a direct developing echinoid, <i>Peronella japonica</i>

The mitogen activated protein (MAP) kinase signaling cascade has been implicated in a wide variety of events during early embryonic development. We investigated the profile of MAP kinase activity during early development in the sea urchin, Strongylocentrotus purpuratus, and tested if disruption of the MAP kinase signaling cascade has any effect on developmental events. MAP kinase undergoes a rapid, transient activation at the early blastula stage. After returning to basal levels, the activity again peaks at early gastrula stage and remains high through the pluteus stage. Immunostaining of early blastula stage embryos using antibodies revealed that a small subset of cells forming a ring at the vegetal plate exhibited active MAP kinase. In gastrula stage embryos, no specific subset of cells expressed enhanced levels of active enzyme. If the signaling cascade was inhibited at any time between the one cell and early blastula stage, gastrulation was delayed, and a significant percentage of embryos underwent exogastrulation. In embryos treated with MAP kinase signaling inhibitors after the blastula stage, gastrulation was normal but spiculogenesis was affected. The data suggest that MAP kinase signaling plays a role in gastrulation and spiculogenesis in sea urchin embryos.

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“…LiCl (Kitazawa & Amemiya 2001 & references therein) A23187 (calcium) (Lane et al . 1993;Akasaka et al .…”

Section: Gastrulationmentioning

confidence: 99%

Inhibition of mitogen activated protein kinase signaling affects gastrulation and spiculogenesis in the sea urchin embryo

Kumano

Foltz

2003

Dev Growth Differ

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“…However, the mechanism of the effect of LiCl on the establishment of LR asymmetry is still unclear. This study showed that LiCl impairs LR asymmetry around the period between the 16-cell and blastula stage, which includes the periods sensitive to the induction of vegetalization (around the 64-to 512-cell stage) shown by Kitazawa and Amemiya (2001) in this species. In the next step, it will be important to determine whether the molecular pathway affected by LiCl that results in the establishment of LR asymmetry is coupled with the pathway for vegetalization.…”

Section: Effect Of Licl On the Lr Asymmetry Of Echinoid Larvaementioning

confidence: 65%

“…This effect of vegetalization, however, had been studied in only indirect developers, and no reports had suggested that LiCl influences the establishment of LR asymmetry in echinoids. We recently investigated the effect of LiCl on a directdeveloping echinoid, P. japonica, and found that LiCl generally causes evagination of invaginating tissues, including both the amniotic cavity and the archenteron (Kitazawa and Amemiya, '97, 2001), and that LiCl causes the embryos to radialize (Kitazawa and Amemiya, 2001).…”

Section: Introductionmentioning

confidence: 99%

LiCl inhibits the establishment of left‐right asymmetry in larvae of the direct‐developing echinoid Peronella japonica

et al. 2004

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The effect of LiCl on the establishment of left-right (LR) asymmetry in larvae of the direct-developing echinoid Peronella japonica was investigated with special attention to the location of the amniotic opening and ciliary band pattern. The larvae of echinoids are LR symmetric, but shortly before metamorphosis the larval LR symmetry is lost as a result of the formation of an amniotic cavity (vestibule), part of the adult rudiment, on the left side of the body. P. japonica has been considered to be the only exception among the echinoids, because the amniotic cavity forms at the midline of the larval body. In the present study we discovered the following two different LR asymmetric traits in larvae of P. japonica: the opening of the amniotic cavity initially forms at the midline of the larval body but shifts to the left dorsal side, and a looped ciliary band that initially forms with LR symmetry becomes LR asymmetric as a result of the formation of a bulge on left dorsal side. The establishment of LR asymmetry in both the location of the amniotic opening and the change in the shape of the ciliary band was influenced by exposing embryos to LiCl. Quantitative analysis of the shift in amniotic opening showed that exposure of embryos to LiCl causes repression of leftward shifting of the amniotic opening in earlier stage larvae, and leftward or rightward shifting in later stage larvae. These findings suggest that LiCl is an effective means of impairing the establishment of LR asymmetry in sea urchin embryos.

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Sea urchin development: An alternative model for mechanistic understanding of neurodevelopment and neurotoxicity

Falugi

Lammerding–Köppel

Aluigi

2008

Birth Defects Research Pt C

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Echinoderm early developmental stages might supply a good tool for toxicity testing in different fields, ranging from environment to food contamination, and in full respect of the 3Rs objectives (reduction, refinement, and replacement of animal experiments) that will eventually lead to the replacement of high vertebrate animal testing in toxicology. Sea urchin is one of the few organismic models considered by the European Agency for Alternative models. Actually, sea urchin embryonic development has been studied for over a century, and the complex nets of intercellular communications leading to the different events are well known, as well the possibility for environmental molecules and their residuals to interfere with such communications, causing developmental anomalies. In particular, the main goal of toxicologists since several years has been to establish a correlation between the cell-to-cell communications occurring during different developmental events and the signals occurring during neurogenesis, with the aim to pursue a mechanistic understanding of these processes and their deviations caused by stressors from different sources.

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Regulating potential in development of a direct developing echinoid, Peronella japonica

Cited by 6 publications

References 42 publications

Inhibition of mitogen activated protein kinase signaling affects gastrulation and spiculogenesis in the sea urchin embryo

Inhibition of mitogen activated protein kinase signaling affects gastrulation and spiculogenesis in the sea urchin embryo

LiCl inhibits the establishment of left‐right asymmetry in larvae of the direct‐developing echinoid Peronella japonica

Sea urchin development: An alternative model for mechanistic understanding of neurodevelopment and neurotoxicity

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