Project description:Sea stars and sea urchins are model systems for interrogating the types of deep evolutionary changes that have restructured developmental gene regulatory networks (GRNs). While cis regulatory DNA evolution is likely the predominant mechanism of change, it was recently shown that Tbrain, a Tbox transcription factor protein, has evolved a changed preference for a low affinity, secondary binding motif, although the primary, high affinity motif is conserved. To date, however, no genome-wide comparisons have been performed in order to provide an unbiased assessment of the evolution of GRNs between these taxa; and no study has attempted to determine the interplay between transcription factor binding motif evolution and GRN topology. The study here measures genome-wide binding of Tbrain orthologs using ChIP-seq, and associates these with putative target genes to assess global function. Targets of both factors are enriched for other regulatory genes, although non-overlapping sets of functional enrichments in the two datasets suggest a much diverged function. The number of low affinity binding motifs are significantly depressed in sea urchins compared to sea star, but both motifs types are associated with genes from a range of functional categories. Only a small fraction (~10%) of genes are predicted to be orthologous targets. Collectively these data indicate that Tbr has evolved significantly different developmental roles in these echinoderms, and that the maintained and unique targets, and their associated binding motifs are dispersed throughout the hierarchy of the GRN, rather than being biased towards terminal process or discrete functional blocks suggesting extensive evolutionary tinkering.
Project description:Marine organisms represent a rich source for discovering natural products and materials that could inspire the development of novel molecules or materials for a high variety of industrial applications. Among them are sea stars, emblematic animals of the seashore. These organisms rely on epidermal secretions to cope with their benthic life. Their integument produces a mucus, which represents the first barrier against invaders; and their tube feet produce adhesive secretions to pry open mussels and attach strongly but temporarily to rocks. In this study, we investigate for the first time the protein content of mucous and adhesive secretions from the sea star Asterias rubens. These secretomes were analysed using tandem mass spectrometry and resulting MS/MS data were searched against in silico translated tube foot transcriptome. Tube foot transcripts coding for proteins identified in the two secretions were then functionally annotated by similarity searches against NCBI nr database.
Project description:Beginning in 2013, sea stars throughout the Eastern North Pacific were decimated by wasting disease, also known as ‘asteroid idiopathic wasting syndrome’ (AIWS) due to its elusive etiology. The geographic extent and taxonomic scale of AIWS meant events leading up to the outbreak were heterogeneous, multifaceted, and oftentimes unobserved; progression from morbidity to death was rapid, leaving few tell-tale symptoms. Here we take a forensic genomic approach to discover candidate genes that may help explain sea star wasting syndrome. We report the first genome and annotation for P. ochraceus, along with differential gene expression (DGE) analyses in four size classes, three tissue types, and in symptomatic and asymptomatic individuals. We integrate nucleotide polymorphisms associated with survivors of the wasting disease outbreak, DGE associated with temperature treatments in P. ochraceus, and DGE associated with wasting in another asteroid Pycnopodia helianthoides. In P. ochraceus, we find DGE across all tissues, among size classes, and between asymptomatic and symptomatic individuals; the strongest wasting-associated DGE signal is in pyloric caecum. We also find previously identified outlier loci co-occur with differentially expressed genes. In cross-species comparisons of symptomatic and asymptomatic individuals, consistent responses distinguish genes associated with invertebrate innate immunity and chemical defense, consistent with context-dependent stress responses, defensive apoptosis, and tissue degradation. Our analyses thus highlight genomic constituents that may link suspected environmental drivers (elevated temperature) with intrinsic differences among individuals (age/size, alleles associated with susceptibility) that elicit organismal responses (e.g. coelomocyte proliferation) and manifest as sea star wasting mass mortality.
Project description:Throughout all kingdoms of life, a large number of adhesive biomolecules have evolved to allow organisms to adhere to surfaces underwater. Proteins play an important role in the adhesion of numerous marine invertebrates (e.g. mussels, sea stars, sea urchins) whereas much less is known about the biological adhesives from marine plants, including the diatoms. Diatoms are unicellular microalgae that together with bacteria dominate marine biofilms in sunlit habitats. In this study we present the first proteomics analyses of the diatom adhesive material isolated from the tenacious fouling species Amphora coffeaeformis. We identified 21 proteins, of which 13 are diatom specific. Ten of these proteins share a conserved C-terminal domain, termed GDPH domain, which is widespread yet not ubiquitously present in all diatom classes. Immunofluorescence localization of a GDPH domain bearing protein (Ac629) as well as two other proteins identified in this study (Ac1442, Ac9617) demonstrated that these are components of the adhesive trails that are secreted by cells that glide on surfaces.
Project description:Duchenne muscular dystrophy (DMD) is characterized by impaired cytoskeleton organization, cytosolic calcium handling oxidative stress and mitochondrial dysfunction. This results in progressive and fatal muscle damage, wasting and weakness. The Striated Muscle activator of Rho signalling (STARS) is an actin binding protein that activates the myocardin-related transcription factor-A (MRTFA)/serum response factor (SRF) transcriptional pathway; a pathway that regulates cytoskeletal structure, muscle function, growth and repair. Here we investigated the regulation of several members of the STARS signalling pathway in muscle from patients with DMD and the dystrophin-deficient mdx and dko (utrophin‐ and dystrophin‐null) mice. A reduction in protein levels of STARS, SRF and RHOA, and an increase in MRTFA were observed in quadriceps muscle of patients with DMD. STARS, SRF and MRTFA mRNA levels were also decreased in DMD muscle, while Stars mRNA levels were decreased in mdx tibialis anterior (TA) muscle and Srf and Mrtfa mRNAs were decreased in dko TA muscle. Overexpressing the human STARS (hSTARS) protein in mdx TA muscle increased maximal isometric specific force by 13%. This was not associated with changes in muscle mass, fibre cross-sectional area (CSA), fibre type, centralized nuclei or collagen deposition. Proteomics screening identified 31 upregulated and 22 downregulated proteins or individual peptides that were significantly regulated by hSTARS overexpression. Pathway enrichment analysis indicated that hSTARS overexpression regulated the keratin, NRF2 and oxidative phosphorylation (OXPHOS) pathways. These pathways are impaired in dystrophic muscle and regulate cytoskeleton organization, oxidative stress and mitochondrial energy production; processes that are vital for muscle function. We conclude that increasing the STARS protein in dystrophic muscle improves muscle force production, potentially via its regulation of multiple pathways that positively influence cytoskeletal structure, oxidative stress and energy production.
Project description:We used microarrays to further detail a transcriptional signature of TRIM44 by globally assessing genes that have changes in expression upon knockdown on TRIM44 using two independent SiRNAs targetting the gene (in duplicate) and All Stars Negative siRNA (in quadruplicate) as a control
Project description:In contrast to women, echinoderms have the amazing ability to keep producing functional gametes throughout their lifespan, in some cases exceeding 200 years. The histology and ultrastructure of echinoderm ovaries has been described but how these ovaries function and maintain the production of high-quality gametes is still a mystery. Here, we present the first single cell RNA sequencing (scRNAseq) datasets of two sea urchin species (Strongylocentrotus purpuratus and Lytechinus variegatus) and one sea star species (Patiria miniata). We find 14 cell states in the Sp ovary, 16 cell states in the Lv ovary and 13 cell states in the ovary of the sea star. This resource is essential to understand the structure and functional biology of the ovary in echinoderms, and better informs decisions in the utilization of in situ RNA hybridization probes selective for various cell types. We link key genes with cell clusters of the feature plots in validation of this approach. This resource also aids in the identification of the stem cells for prolonged and continuous gamete production, is a foundation for testing changes in the annual reproductive cycle, and is essential for understanding the evolution of reproduction of this important phylum. Highly selective gene expression revealed by this dataset also divulges gene targets of highest priority for interrogating gene activities by Cas9-targeted gene knock-out and knock-in approaches and in dissociated ovarian cell cultures to test the function of each cell type identified.
2023-11-29 | GSE246430 | GEO
Project description:The microbial landscape of sea stars and the intra-animal variability of their microbiome