Project description:Collagenous connective tissue is responsible for body integrity in all multicellular organisms and has many biomedical applications within a multibillion-dollar industry. An inspiration for a new generation of collagen-based biomaterials with a wide range of applications may come from echinoderms, a group of marine invertebrates that includes sea stars, sea cucumbers, brittle stars, sea urchins, and sea lilies. Echinoderms are capable of reversibly controlling the pliability of certain connective tissue components (i.e., tendons and ligaments) that are composed of mutable collagenous tissue (MCT). The MCTs variable tensility allows echinoderms to perform unique functions, including energy-saving posture maintenance, autotomy, and asexual reproduction. It is known that neurosecretory juxtaligamental cells in the nervous system control the MCT. These cells release substances that either soften or stiffen the MCT. So far, only a few of these substances have been purified and characterized, and the genomics behind MCT biology are still mostly unknown. Therefore, we propose to identify the putative MCT-related genes in echinoderms and better understand the biology of the juxtaligamental cells. Our research improves our knowledge about the MCT molecular control mechanism, with the ultimate goal of unlocking new biomaterial applications. In this project, we utilize RNA-Seq to identify and annotate differentially expressed genes in the MCT structures of the brittle star Ophiomastix wendtii
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:Recent studies have unveiled the deep sea as a rich biosphere, populated by species descended from shallow-water ancestors post-mass extinctions. Research on genomic evolution and microbial symbiosis has shed light on how these species thrive in extreme deep-sea conditions. However, early adaptation stages, particularly the roles of conserved genes and symbiotic microbes, remain inadequately understood. This study examined transcriptomic and microbiome changes in shallow-water mussels Mytilus galloprovincialis exposed to deep-sea conditions at the Site-F cold seep in the South China Sea. Results reveal complex gene expression adjustments in stress response, immune defense, homeostasis, and energy metabolism pathways during adaptation. After 10 days of deep-sea exposure, shallow-water mussels and their microbial communities closely resembled those of native deep-sea mussels, demonstrating host and microbiome convergence in response to adaptive shifts. Notably, methanotrophic bacteria, key symbionts in native deep-sea mussels, emerged as a dominant group in the exposed mussels. Host genes involved in immune recognition and endocytosis correlated significantly with the abundance of these bacteria. Overall, our analyses provide insights into adaptive transcriptional regulation and microbiome dynamics of mussels in deep-sea environments, highlighting the roles of conserved genes and microbial community shifts in adapting to extreme environments.
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