Search results for " sea urchin."

Climate change potentially affect keystone predation in subtidal system.

2014

Metallothionein genes in sea urchin embryos and their induction by cadmium

2012

Metallothioneins (MTs) are proteins that play a major role in metal homeostasis and as a reservoir. The MT gene/protein systems of sea urchins are an invaluable model for the study of gene expression regulation and MT isoform-specific functionality of these proteins. We isolated five paralogous MT isogenes and we studied their expression in the sea urchin embryo Paracentrotus lividus. The Cadmium-dependent transcriptional activation of the five isogenes was assessed using quantitative Real Time PCR. Two of the five P. lividus MT (MT-7 and MT-8) isogenes appeared to be constitutively expressed and upregulated upon cadmium treatment. Three isogenes (MT-4/MT-6) are not transcribed in control e…

Genome wide survey of the Toll-like receptor family in the Mediterranean sea urchin

Toll-like receptors (TLRs) represent a conserved family of proteins widely expressed in eukaryotes. They play crucial roles in the innate immune system recognizing different pathogen-associated molecular patterns. In mammals the TLR family comprises 10-13 members, while a huge number of TLR-like genes were recovered in S.purpuratus[1-3]. The Paracentrotus lividus genome project recently generated a new highquality assembly of the genome that represents a valuable resource also for clarifying the evolutionary origin of immune system. In order to identify TLR genes in P.lividus, a genome wide survey was carried out and BLAT searches retrieved 119 TLR genes (PlivTLRs). Ab initio gene predictio…

Enhancer, chromatin insulator, non-coding RNA and α-histone gene expression during embryogenesis of the sea urchin Paracentrotus lividus.

2009

Core promoters and chromatin insulators (ins) may direct a transcriptional enhancer (enh) to prefer a specific promoter in complex genetic loci. Enh and ins flank the sea urchin Paracentrotus lividus α-histone H2A transcription unit in a tandem repeated cluster containing the five histone genes. In vivo competition assays of enh and ins functions reveal that the H2A enh-bound MBF-1 activator participates also in the expression of the H3 gene and that the sns5 ins buffers the downstream H1 promoter from the H2A enh. These results suggest that both the H2A enh and the sns5 ins may account for the diverse accumulation of the linker vs core nucleosomal histones during early development of the s…

The sea urchin sns5 chromatin insulator settles a gene therapy vector into an independent domain of expression in the vertebrate genome

2014

One of the critical aspects of introducing a transgene into the eukaryotic genome is the great variability of gene expression due to position effects (1). Chromatin-dependent repressive states could be overcome by incorporation in the transgene of chromatin insulators, functioning to establish and delimit domains of expression. We have previously demonstrated that the sea urchin sns5 DNA element has the typical features of an insulator: by acting as enhancer blocker, it shields promoters from neighboring regulatory elements, and by acting as barrier it buffers a transgene from the propagation of condensed chromatin (2,3). We have investigated the use of sns5 in the field of gene therapy. Ou…

Suppression of nodal expression in prospective dorsal cells of the early sea urchin embryo by the hbox12 homeodomain regulator

2014

Dorsal/Ventral (DV) axis formation in the sea urchin embryo depends upon the expression of nodal on the ventral side, which behaves as a DV organizing centre. However, only fuzzy clues are known as to the early symmetry-breaking steps that lead to the positioning of such an organizer. An extremely interesting candidate for this role is the hbox12 homeobox-containing gene. In Paracentrotus lividus, hbox12 expression is antecedent and complementary with respect to that of nodal, being confined in prospective dorsal cells. We show that ectopic expression of Hbox12 provokes DV abnormalities and attenuates nodal as well as nodal-dependent gene transcription. By blastomere transplantation, we als…

Functional studies of regulatory genes in the sea urchin embryo.

2009

p38 MAPK activation is required for Paracentrotus lividus skeletogenesis

2008

We investigated the p38 MAPK role during sea urchin, Paracentrotus lividus, development. We found that at the morula stage, before the onset of skeletogenesis, p38 MAPK shows a peak of activity, and we tested whether p38 MAPK activity has any effect on skeletogenesis. By immunohistochemistry on whole-mount embryos we show the preferential localization of the active p38 form both in the presumptive PMCs and bilateral spiculo- genesis centers in control embryos, and in the radialized supernumerary spiculogenesis centers induced by NiCl2 treatment. By using SB203580, a p38 MAPK specific inhibitor, we show that p38 activity is required both for the initial triradiate spicule rudiments formation…

Relative role of fish vs. starfish predation in controlling sea urchin populations in Mediterranean rocky shores

2009

In the Mediterranean, fishing bans generally allow the recovery of populations of sea urchin predators, such as the seabreams Diplodus sargus and D. vulgaris, promoting the transformation of overgrazed communities into ones dominated by erect macroalgae. However, in the marine reserve on Ustica Island (SW Italy) the opposite trend has occurred in the upper infralittoral community, and urchin barrens formed after the cessation of fishing activities. We hypothesized that (1) the natural scarcity of the 2 seabream species leads to a low predation rate on sea urchins at Ustica, and (2) predation rate varies with depth, due to differences in the predator assemblages. Tethering experiments were c…

A FOX Binding Site is Necessary for the Activation of Pl-Tuba1a Gene in the neurogenic domains

2016

All echinoderm larvae possess a nervous system consisting of a ciliary band and associated sensory ganglia (apical, oral and lateral ganglia) that controls swimming and feeding. Neurons of the larval nervous system first appear as neuroblasts in the thickened ectoderm of the animal plate (anterior neuroectoderm, ANE) at the late blastula – early gastrula stage and then also in the ciliary band. The neural differentiation process of sea urchin embryos has been analysed and the Gene Regulatory Network involved in the differentiation processes is extensively studied. We have previously isolated an alpha tubulin family member of the sea urchin Paracentrotus lividus (Pl-Tuba1a, formerly known as…