Project description:Seawater exposure to the gram negative marine bacterium Vibrio diazotrophicus induces a robust cellular response in sea urchin larvae that includes the migration of pigment cells to the gut epithelium, changes in cell behavior and altered gut morphology (Ho et al., 2016; PMID 27192936). To investigate the transcriptional underpinnings of this response, whole transcriptome sequencing was performed on mRNA isolated from larval samples collected at 0, 6, 12 and 24 hr of exposure to V. diazotrophicus. The morphological simplicity of the sea urchin larva provides a systems-level model for identifying biologically relevant transcriptional state changes in response to dysbiosis in the gut lumen.
Project description:We identified cis-regulatory elements based on their dynamic chromatin accessibility during the gastrula-larva stages of sea urchin and sea star and studied their evolution in these echinoderm species
Project description:Sea urchins lack proper eye organs but are photosensitive. In this study, we investigate an extraocular photoreceptor cell (PRC) system in developmental stages of the sea urchin Paracentrotus lividus.
Project description:Using hMeDIP-seq we validated the single-base resolution hydroxymethylomes (ACE-seq) of sea urchin, lancelet and zebrafish embryos.
Project description:Purpose: The Tbrain transcription factor has demonstrated an evolved preference for low-affinity, secondary site binding motifs between the sea star and sea urchin orthologs. We sought to identify targets of sea urchin and sea star orthologs of Tbr. Because less is known about the function of Tbr during sea star development, we used RNA-seq in conjuction with ChIP-seq studies (GEO:xxxx) to determine the targets of sea star Tbr in early development. Methods: Sea star (Patiria miniata) embryos were injected with translation-blocking morpholino antisense oligonucleotides to knock-down PmTbr expression, as described previously. Control morpholinos were injected into sibling embryos. Embryos were allowed to develop until hatching (30-36 hpf) at which point injected embryos were collected and RNA was extracted. RNA-seq libraries were prepared, sequenced, and analyzed using standard protocols. Results: There are 2,562 genes that are significantly differentially expressed relative to control morpholino inected embryos (FDR < 0.05). There are roughly equivalent numbers of genes down-regulated (1,041) and up-regulated (1,521) by Pm-tbr knockdown, suggesting that PmTbr may act as both a transcriptional activator and repressor. 1,165 differentially expressed genes are located within 75 kb of a PmTbr binding site determined using ChIP-seq, and this set is used as a basis for comparison between sea star and sea urchin binding sites. Conclusions: 1,165 targets of the PmTbr transcription factor were identified based on differential expression following knockdown and the presence of transcription factor binding sites proximal to differentially expressed genes. There are an equal number of up- and down-regulated targets, suggesting Tbr may function as a transcriptional activator and repressor, depending on context and target gene. There was no clear association of motif utilization with either the direction of differential expression or ontological category of the target gene. There are only a small fraction of target genes (approximately 10%) that are in common between the sea star and sea urchin sets.
Project description:Marine bioadhesives have unmatched performances especially in wet environments, being valuable sources of inspiration for industrial and biomedical applications. In sea urchins specialized adhesive organs, called tube feet, mediate adhesion. These are composed by a disc, which produces adhesive and de-adhesive secretions for strong reversible attachment, and a motile stem. After detachment, the secreted adhesive remains bound to the substratum as a footprint. Previous studies showed that sea urchin adhesive is composed of proteins and sugars, but so far only one protein, Nectin, was shown to be over-expressed as a transcript in tube feet discs, suggesting its involvement in sea urchin adhesion. Here we use high-resolution quantitative mass-spectrometry technologies to profile Paracentrotus lividus tube feet differential proteome, comparing protein expression levels in its adhesive part (disc) versus the non-adhesive part (stem). This allowed us to identify 163 highly over-expressed disc proteins and propose the first molecular model of sea urchin reversible adhesion. The secreted adhesive proteome was also analyzed, whereby we found that 70% of its components fall within five protein groups, involved in adhesive exocytosis and protection against microbes. Our data also provides evidence that Nectin is not only highly expressed in tube feet discs but is a component of the adhesive itself, thus constituting the first report of a sea urchin tube foot adhesive protein. These results give us an unprecedented insight on the molecular mechanics underlying sea urchins reversible adhesion, opening new doors to develop new, wet-reliable, reversible, efficient, ecological biomimetic adhesives.
