...Odile Bronchain; Bertrand Ducos; Harald Putzer; Marine Delagrange; Soumaya Laalami; Laetitia Philippe-Caraty; Krystel Saroul; Brigitte Ciapa ABSTRACT One presenilin gene ( PSEN ) is expressed in the sea urchin embryo, in the vegetal pole of the gastrula and then mainly in cilia cells located around...

..., which makes their role in a given cell and/or organism complex to decipher. We have established the Paracentrotus lividus sea urchin embryo as a new model to study the role of PSEN. In the sea urchin embryo, the PSEN gene is present in unduplicated form and encodes a protein highly similar to human...

... early development, which is accompanied by rapid cell cycle progression and dynamic changes in nuclear organization, such as nuclear size and chromatin constitution. In this study, we focused on the early development of the sea urchin Hemicentrotus pulcherrimus and performed three-dimensional...

... in flagella, thus providing the basis for flagellar oscillation. * Author for correspondence (e-mail: [email protected] ) 16 6 2008 © The Company of Biologists Limited 2008 2008 Dynein Flagella Oscillation Imposed bending Sperm Sea urchin Oscillatory bending...

...Wen Ling Zhang; Philippe Huitorel; Anne-Marie Geneviere; Sandrine Chiri; Brigitte Ciapa Unfertilized sea urchin eggs that are arrested at G1 phase after completion of meiosis contain a highly phosphorylated mitogen-activated protein (MAP) kinase (MAPK), the ERK-like protein (ERK-LP). Several data...

... to mRNA. We have previously shown that fertilization of sea urchin eggs triggers eIF4E–4E-BP complex dissociation and 4E-BP degradation. Here, we show that microinjection of eIF4E-binding motif peptide into unfertilized eggs delays the onset of the first mitosis triggered by fertilization, demonstrating...

..., and formation of inositol trisphosphate. However, the upstream activators or modulators of this signaling pathway are not known. We recently identified four Gα subunits of heterotrimeric G-proteins present in the sea urchin egg, and here we find that activation of G-proteins of the Gα s and Gα q type...

... of ATP. While sensitive to thiol-specific reagents, CV exocytosis is not restored by the addition of cytosolic NSF, and fusion and NSF function are differentially sensitive to thiol-specific agents. To test participation of tightly bound, non-exchangeable NSF in CV-CV fusion, we cloned the sea urchin...

...Bradley J. Schnackenberg; William F. Marzluff In somatic cells, cyclin E-cdk2 activity oscillates during the cell cycle and is required for the regulation of the G1/S transition. Cyclin E and its associated kinase activity remain constant throughout early sea urchin embryogenesis, consistent...

... divisions. Furthermore, we observed that wortmannin, an inhibitor of PI 3-kinase that arrests the fertilized sea urchin eggs at the prometaphase stage, inhibited the inactivation of MAP kinase normally observed when the eggs divide, suggesting a role for PI 3-kinase in the deactivation process of MAP kinase...

...Céline De Nadai; Philippe Huitorel; Sandrine Chiri; Brigitte Ciapa ABSTRACT We have reported earlier that the polyphosphoinositide messenger system may control mitosis in sea urchin eggs. Besides phospholipase C activation and its second messengers, phosphatidylinositol (PI) 3-kinase has been...

... and screened a panel of monoclonal antibodies (mAb) generated against sea urchin sperm axonemal proteins. Antibodies were selected for their ability to block the motility of permeabilized sperm models. The antitubulin mAb B3 completely inhibited, at low concentrations, the flagellar motility of permeabilized...

...Eric Scott Bachman; David R. McClay ABSTRACT We have investigated the distribution and function of an ezrin-radixin-moesin-like (ERM) molecule in the sea urchin. A sea urchin homologue of moesin was cloned that shares 75% amino acid similarity in the conserved N-terminal region to other moesin...

...Nancy M. Mozingo; Cynthia E. Somers; Douglas E. Chandler ABSTRACT Ovoperoxidase is a cortical granule-derived enzyme that hardens the sea urchin fertilization envelope by catalyzing the formation of dityrosine residues. Ovoperoxidase works in concert with a second protein, proteoliaisin, which...

...Etsuo Yokota; Issei Mabuchi ABSTRACT A novel dynein (C/A dynein), which is composed of C and A heavy chains, two intermediate chains and several light chains, was isolated from sea urchin sperm flagella. The C/A dynein was released by the treatment with 0.7 M NaCl plus 5 mM ATP from the axonemes...

...Etsuo Yokota; Issei Mabuchi ABSTRACT C/A dynein is a novel dynein isolated from sea urchin sperm flagellar axonemes. It is composed of C and A heavy chains and some additional lower molecular mass polypeptide chains. The characterization of ATPase activity and the interaction of this dynein...

...R. E. Stephens ABSTRACT Tubulin is the major protein found in the membrane/periaxonemal matrix fraction of mature sea urchin embryonic cilia but its distribution and possible function during ciliary assembly are unknown. Hypertonic salt may be used to deciliate the embryos, allowing synchronous...

... of centrioles it contains. In other experiments we show that centrosome reproduction is cytoplasmi- cally controlled; centrosomes repeatedly double in a normal fashion in physically enucleated sea urchin eggs and eggs in which DNA synthesis has been inhibited by aphidicolin. In addition, we show...