Search results for "OTU"
showing 10 items of 2539 documents
EGFR signalling is required for Paracentrotus lividus endomesoderm specification
2008
The EGFR pathway is critical for cell fate specification throughout the development of several organisms. Here we identified in sea urchin an EGFR-related antigen maternally expressed and showing a dynamic pattern of localization during development. To investigate the role played by the EGFR in Paracentrotus lividus development we blocked its activity by using the EGFR kinase inhibitor AG1478. This treatment produces decrease of EGFR phosphorylation, and embryos with various defects especially in the endomesoderm territory until to obtain an animalized phenotype. These effects are rescued by the addition of TGF-alpha, an EGFR ligand. The role played by EGFR-like along the animal/vegetal axi…
In silico characterization of the neural alpha tubulin gene promoter of the sea urchin embryo Paracentrotus lividus by phylogenetic footprinting
2011
During Paracentrotus lividus sea urchin embryo development one alpha and one beta tubulin genes are expressed specifically in the neural cells and they are early end output of the gene regulatory network that specifies the neural commitment. In this paper we have used a comparative genomics approach to identify con- served regulatory elements in the P. lividus neural alpha tubulin gene. To this purpose, we have first isolated a genomic clone containing the entire gene plus 4.5 Kb of 5 0 upstream sequences. Then, we have shown by gene transfer experiments that its non-coding region drives the spatio- temporal gene expression corresponding substantially to that of the endogenous gene. In addi…
Toxicity of vanadium during development of sea urchin embryos: bioaccumulation, calcium depletion, ERK modulation and cell-selective apoptosis
2022
Vanadium toxicology is a topic of considerable importance as this metal is widely used in industrial and biomedical fields. However, it represents a potential emerging environmental pollutant because wastewater treatment plants do not adequately remove metal compounds that are subsequently released into the environment. Vanadium applications are limited due to its toxicity, so it is urgent to define this aspect. This metal is associated with sea urchin embryo toxicity as it perturbs embryogenesis and skeletogenesis, triggering several stress responses. Here we investigated its bioaccumulation and the correlation with cellular and molecular developmental pathways. We used cytotoxic concentra…
Function of RAR? and RAR?2 at the initiation of retinoid signaling is essential for avian embryo survival and for distinct events in cardiac morphoge…
2003
Avian embryogenesis requires retinoid receptor activation by the vitamin A active form, retinoic acid (RA), during neurulation. We conducted loss-of-function analysis in quail embryos by nutritional deprivation of RA and by blocking generation of retinoid receptors. Here we identify a distinct role for RARα2 in cardiac inflow tract morphogenesis and for RARγ in cardiac left/right orientation and looping morphogenesis. Blocking normal embryos with antisense oligonucleotides to RARα2 or RXRα diminishes GATA-4 transcripts, while blocking RARγ or RXRα diminishes nodal and Pitx2 transcripts; the expression of these genes in the heart forming region resembles that of the vitamin A-deficient embry…
DNA-methylation dependent regulation of embryo-specific 5S ribosomal DNA cluster transcription in adult tissues of sea urchin Paracentrotus lividus
2013
Abstract We have previously reported a molecular and cytogenetic characterization of three different 5S rDNA clusters in the sea urchin Paracentrotus lividus and recently, demonstrated the presence of high heterogeneity in functional 5S rRNA. In this paper, we show some important distinctive data on 5S rRNA transcription for this organism. Using single strand conformation polymorphism (SSCP) analysis, we demonstrate the existence of two classes of 5S rRNA, one which is embryo-specific and encoded by the smallest (700 bp) cluster and the other which is expressed at every stage and encoded by longer clusters (900 and 950 bp). We also demonstrate that the embryo-specific class of 5S rRNA is ex…
Early asymmetric cues triggering the dorsal/ventral gene regulatory network of the sea urchin embryo
2014
Dorsal/ventral (DV) patterning of the sea urchin embryo relies on a ventrally-localized organizer expressing Nodal, a pivotal regulator of the DV gene regulatory network. However, the inceptive mechanisms imposing the symmetry-breaking are incompletely understood. In Paracentrotus lividus, the Hbox12 homeodomain-containing repressor is expressed by prospective dorsal cells, spatially facing and preceding the onset of nodal transcription. We report that Hbox12 misexpression provokes DV abnormalities, attenuating nodal and nodal-dependent transcription. Reciprocally, impairing hbox12 function disrupts DV polarity by allowing ectopic expression of nodal. Clonal loss-of-function, inflicted by b…
Sea urchin embryos as a model system for studying autophagy induced by cadmium stress
2011
It is well known that sea urchin embryos are able to activate different defense strategies against stress. We previously demonstrated that cadmium treatment triggers the accumulation of metal in embryonic cells and the activation of defense systems depending on concentration and exposure time, through the synthesis of heat shock proteins and/or the initiation of apoptosis. Here we show that Paracentrotus lividus embryos exposed to Cd adopt autophagy as an additional stratagem to safeguard the developmental program. At present, there are no data focusing on the role of this process in embryo development of marine organisms. In this paper we utilized different techniques to detect autophagy i…
EGTA treatment causes the synthesis of heat shock proteins in sea urchin embryos.
2000
Paracentrotus lividus embryos, at post-blastular stage, when subjected to a rise in temperature from physiologic (20 degrees C) to 31 degrees C, synthesize a large group of heat shock proteins (hsps), and show a severe inhibition of bulk protein synthesis. We show, by mono- and two-dimensional electrophoresis, that also EGTA (ethylene glycol-bis[beta-aminoethyl ether] tetraacetic acid) treatment induces in sea urchin embryos both marked inhibition of bulk protein synthesis and the synthesis of the entire set of hsps. Furthermore, EGTA-treated sea urchin embryos are able to survive at a temperature otherwise lethal (35 degrees C) becoming thermotolerant. Because incubation with a different c…
Cadmium induces an apoptotic response in sea urchin embryos.
2007
Cadmium is a heavy metal toxic for living organisms even at low concentrations. It does not have any biological role, and since it is a permanent metal ion, it is accumulated by many organisms. In the present paper we have studied the apoptotic effects of continuous exposure to subacute/sublethal cadmium concentrations on a model system: Paracentrotus lividus embryos. We demonstrated, by atomic absorption spectrometry, that the intracellular amount of metal increased during exposure time. We found, using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay, that long treatments with cadmium triggered a severe DNA fragmentation. We demonstrated, by immunocytochemistry …
Highly restricted expression at the ectoderm–endoderm boundary of PIHbox 9, a sea urchin homeobox gene related to the human HB9 gene
1998
Abstract Characterisation of a sea urchin (P. lividus) homeobox gene PIHbox 9 is reported. The homeodomain of PIHbox9 is 95% identical to the homeodomain of the human HB9 gene, indicating that the two genes are highly related. Temporal expression analysis during sea urchin embryogenesis showed an absence of transcripts at early cleavage stages. At late gastrula stage, transcripts were barely detectable and reached the highest abundance at prism/early pluteus stages. By whole mount in situ hybridisation we observed a highly restricted expression in a few cells of the ectoderm–endoderm boundary of embryos at the prism stage. At pluteus stages, expression of PIHbox 9 was confined around the an…