Extracellular carbonic anhydrase activity promotes a carbon concentration mechanism in metazoan calcifying cells.

Many calcifying organisms utilize metabolic CO2 to generate CaCO3 minerals to harden their shells and skeletons. Carbonic anhydrases are evolutionary ancient enzymes that have been proposed to play a key role in the calcification process, with the underlying mechanisms being little understood. Here, we used the calcifying primary mesenchyme cells (PMCs) of sea urchin larva to study the role of cytosolic (iCAs) and extracellular carbonic anhydrases (eCAs) in the cellular carbon concentration mechanism (CCM). Molecular analyses identified iCAs and eCAs in PMCs and highlight the prominent expression of a glycosylphosphatidylinositol-anchored membrane-bound CA (Cara7). Intracellular pH recordings in combination with CO2 pulse experiments demonstrated iCA activity in PMCs. iCA activity measurements, together with pharmacological approaches, revealed an opposing contribution of iCAs and eCAs on the CCM. H+-selective electrodes were used to demonstrate eCA-catalyzed CO2 hydration rates at the cell surface. Knockdown of Cara7 reduced extracellular CO2 hydration rates accompanied by impaired formation of specific skeletal segments. Finally, reduced pHi regulatory capacities during inhibition and knockdown of Cara7 underscore a role of this eCA in cellular HCO3- uptake. This work reveals the function of CAs in the cellular CCM of a marine calcifying animal. Extracellular hydration of metabolic CO2 by Cara7 coupled to HCO3- uptake mechanisms mitigates the loss of carbon and reduces the cellular proton load during the mineralization process. The findings of this work provide insights into the cellular mechanisms of an ancient biological process that is capable of utilizing CO2 to generate a versatile construction material.

The gene regulatory control of sea urchin gastrulation.

The cell behaviors associated with gastrulation in sea urchins have been well described. More recently, considerable progress has been made in elucidating gene regulatory networks (GRNs) that underlie the specification of early embryonic territories in this experimental model. This review integrates information from these two avenues of work. I discuss the principal cell movements that take place during sea urchin gastrulation, with an emphasis on molecular effectors of the movements, and summarize our current understanding of the gene regulatory circuitry upstream of those effectors. A case is made that GRN biology can provide a causal explanation of gastrulation, although additional analysis is needed at several levels of biological organization in order to provide a deeper understanding of this complex morphogenetic process.

In vitro study of the scolicidal effects of Echinometra mathaei spine and shell extracts on hydatid cyst protoscolices.

Hydatid cyst is a zoonotic parasitic infection caused by the tapeworm Echinococcus granulosus. Such infections are of considerable public health and economic concern, and new effective treatments are intensely sought. Sea urchin (Salmacis virgulata) shell extracts have potent antimicrobial and antioxidant activity, and spines of several species of echinoderms also show antimicrobial activity. In the present in vitro study, we investigated the scolicidal effect of spines and shells extractions from Echinometra mathaei obtained from the Persian Gulf. Spines and shells from the sea urchin, Echinometra mathaei were used in the tests. Spines and shells from 800 specimens were extracted with dibasic sodium phosphate buffer (pH 7.5). Procedures used protoscolices of E. granulosus were obtained aseptically from hydatid cyst in naturally infected sheep's liver and goats and viable protoscolices exposed with spine and shell extractions. The apoptosis was assessed by measuring the caspase 3 activity of the extract-treated protoscolices, using ELISA-based commercial kits to determine caspase activity. The scolicidal effects of shells were also showed, 20 µg/ml of shell extracts after 60 min exposure, the viability of protoscolices were 21.99 ±â€¯0.01. The results showed that 20 µg/ml of spines gave maximum scolicidal activity (p < 0.05). This study represents the first attempt at combatting echinoid parasites by natural compounds with high efficiency, and may provide a base for future treatment of hydatid cysts.

Markers of oil exposure in cold-water benthic environments: Insights and challenges from a study with echinoderms.

In spite of increasing naval activities and petroleum exploration in cold environments, there is currently a paucity of tools available to monitor oil contamination in boreal marine life, especially in sedentary (non-fish) species that dominate benthic communities. This research aimed to identify biotic sources of variation in biomarkers using subarctic echinoderms, and to identify suitable biomarkers of their exposure to hydrocarbons. The focal species included the sea star Asterias rubens, the brittle star Ophiopholis aculeata, the sea urchin Strongylocentrotus droebachiensis, and the sea cucumber Cucumaria frondosa, which are among the most abundant echinoderms in the North Atlantic and Arctic Oceans. The latter two species are also commercially exploited. A series of 96-h acute exposures of the water-accommodating fraction (WAF) of used lubricating oil (ULO) were performed in different seasons (i.e. distinct reproductive stages). Digestive and reproductive tissues were analyzed for baseline and response levels of glutathione peroxidase (GPx) and ethoxyresorufin-O-deethylase (EROD). GPx activity was detected in the pyloric caecum, stomach, and gonad of sea stars, the intestine and gonad of sea cucumbers, and the gonad of brittle stars and sea urchins. No seasonal variation in baseline GPx activity occurred. Upon exposure to the ULO WAF, sex-based differences were elicited in the GPx activity of sea star stomachs (lower in females than males). EROD activity was present in the pyloric caeca of sea stars, and the gonads of brittle stars and sea urchins. An interaction between season and sex on baseline EROD activity was measured in the gonads of sea urchins. Ovaries exhibited significant seasonal variation in EROD activity and had greater activity than testes during the spawning and post-spawning seasons. Seasonal variation in EROD activity also occurred in sea star pyloric caeca and brittle star gonads. Furthermore, testes of sea urchins exposed to the ULO WAF exhibited suppressed EROD activity compared to baseline levels. The nearly universal presence of GPx activity highlights its potential as a useful biomarker, while EROD activity was much more limited. Findings suggest a complex relationship between temporal and biotic factors on both the baseline and response levels of enzymatic activity, emphasizing the need to consider sex and sampling season in studies of biomarkers of hydrocarbon exposure in boreal indicator species that display annual reproductive cycles.

Structure and function of echinoderm telomerase RNA.

Telomerase is a ribonucleoprotein (RNP) enzyme that requires an integral telomerase RNA (TR) subunit, in addition to the catalytic telomerase reverse transcriptase (TERT), for enzymatic function. The secondary structures of TRs from the three major groups of species, ciliates, fungi, and vertebrates, have been studied extensively and demonstrate dramatic diversity. Herein, we report the first comprehensive secondary structure of TR from echinoderms-marine invertebrates closely related to vertebrates-determined by phylogenetic comparative analysis of 16 TR sequences from three separate echinoderm classes. Similar to vertebrate TR, echinoderm TR contains the highly conserved template/pseudoknot and H/ACA domains. However, echinoderm TR lacks the ancestral CR4/5 structural domain found throughout vertebrate and fungal TRs. Instead, echinoderm TR contains a distinct simple helical region, termed eCR4/5, that is functionally equivalent to the CR4/5 domain. The urchin and brittle star eCR4/5 domains bind specifically to their respective TERT proteins and stimulate telomerase activity. Distinct from vertebrate telomerase, the echinoderm TR template/pseudoknot domain with the TERT protein is sufficient to reconstitute significant telomerase activity. This gain-of-function of the echinoderm template/pseudoknot domain for conferring telomerase activity presumably facilitated the rapid structural evolution of the eCR4/5 domain throughout the echinoderm lineage. Additionally, echinoderm TR utilizes the template-adjacent P1.1 helix as a physical template boundary element to prevent nontelomeric DNA synthesis, a mechanism used by ciliate and fungal TRs. Thus, the chimeric and eccentric structural features of echinoderm TR provide unparalleled insights into the rapid evolution of telomerase RNP structure and function.

cDNA cloning and expression of Contractin A, a phospholipase A2-like protein from the globiferous pedicellariae of the venomous sea urchin Toxopneustes pileolus.

Venomous sea urchins contain various biologically active proteins that are toxic to predators. Contractin A is one such protein contained within the globiferous pedicellariae of the venomous sea urchin Toxopneustes pileolus. This protein exhibits several biological activities, such as smooth muscle contraction and mitogenic activity. N-terminal amino acid residues of Contractin A have been determined up to 37 residues from the purified protein. In this study, we cloned cDNA for Contractin A by reverse transcription-PCR using degenerate primers designed on the basis of its N-terminal amino acid sequence. Analysis of the cDNA sequence indicated that Contractin A is composed of 166 amino acid residues including 31 residues of a putative signal sequence, and has homology to the sequence of phospholipase A2 from various organisms. In this study, recombinant Contractin A was expressed in Escherichia coli cells, and the protein was subjected to an assay to determine lipid-degrading activity using carboxyfluorescein-containing liposomes. As a result, Contractin A was found to exhibit Ca(2+)-dependent release of carboxyfluorescein from the liposomes, suggesting that Contractin A has phospholipase A2 activity, which may be closely associated with its biological activities.

H(+)/K(+) ATPase activity is required for biomineralization in sea urchin embryos.

The bioelectrical signatures associated with regeneration, wound healing, development, and cancer are changes in the polarization state of the cell that persist over long durations, and are mediated by ion channel activity. To identify physiologically relevant bioelectrical changes that occur during normal development of the sea urchin Lytechinus variegatus, we tested a range of ion channel inhibitors, and thereby identified SCH28080, a chemical inhibitor of the H(+)/K(+) ATPase (HKA), as an inhibitor of skeletogenesis. In sea urchin embryos, the primary mesodermal lineage, the PMCs, produce biomineral in response to signals from the ectoderm. However, in SCH28080-treated embryos, aside from randomization of the left-right axis, the ectoderm is normally specified and differentiated, indicating that the block to skeletogenesis observed in SCH28080-treated embryos is PMC-specific. HKA inhibition did not interfere with PMC specification, and was sufficient to block continuing biomineralization when embryos were treated with SCH28080 after the initiation of skeletogenesis, indicating that HKA activity is continuously required during biomineralization. Ion concentrations and voltage potential were abnormal in the PMCs in SCH28080-treated embryos, suggesting that these bioelectrical abnormalities prevent biomineralization. Our results indicate that this effect is due to the inhibition of amorphous calcium carbonate precipitation within PMC vesicles.

Jun N-terminal kinase activity is required for invagination but not differentiation of the sea urchin archenteron.

Although sea urchin gastrulation is well described at the cellular level, our understanding of the molecular changes that trigger the coordinated cell movements involved is not complete. Jun N-terminal kinase (JNK) is a component of the planar cell polarity pathway and is required for cell movements during embryonic development in several animal species. To study the role of JNK in sea urchin gastrulation, embryos were treated with JNK inhibitor SP600125 just prior to gastrulation. The inhibitor had a limited and specific effect, blocking invagination of the archenteron. Embryos treated with 2 µM SP600125 formed normal vegetal plates, but did not undergo invagination to form an archenteron. Other types of cell movements, specifically ingression of the skeletogenic mesenchyme, were not affected, although the development and pattern of the skeleton was abnormal in treated embryos. Pigment cells, derived from nonskeletogenic mesenchyme, were also present in SP600125-treated embryos. Despite the lack of a visible archenteron in treated embryos, cells at the original vegetal plate expressed several molecular markers for endoderm differentiation. These results demonstrate that JNK activity is required for invagination of the archenteron but not its differentiation, indicating that in this case, morphogenesis and differentiation are under separate regulation.

Pollutant resilience in embryos of the Antarctic sea urchin Sterechinus neumayeri reflects maternal antioxidant status.

Legacy pollutants, including polycyclic aromatic hydrocarbons (PAHs) and metals, can occur in high concentrations in some Antarctic marine environments, particularly near scientific research stations. Oxidative stress is an important unifying feature underlying the toxicity of many chemical contaminants to aquatic organisms. However, the potential impacts of pollutants on the oxidative physiology of Antarctic marine invertebrates are not well documented. Sterechinus neumayeri is a common animal in the shallow subtidal benthos surrounding Antarctica, and is considered an important keystone species. The aim of the present study was to collect baseline oxidative biomarker data for S. neumayeri and to investigate the impacts of field exposure to chemical contaminants on gamete health and parent-to-offspring transfer of oxidative stress resilience. We analysed antioxidant enzyme activities, levels of the molecular antioxidant glutathione, protein carbonylation, lipid peroxidation and levels of 8-OHdG as oxidative stress biomarkers in S. neumayeri from a contaminant-impacted site near McMurdo Station and a relatively pristine site at Cape Evans. Biomarkers were analysed in adult gamete tissue and in early stage embryos exposed to AN8 fuel oil. PAHs were quantified as a proxy for contamination and were found to be elevated in urchins from the contaminated site (up to 231.67ng/g DW). These contaminant-experienced adult urchins produced eggs with greater levels of a broad suite of antioxidants, particularly superoxide dismutase, catalase and glyoxalase-I, than those from Cape Evans. In addition, embryos that were derived from contaminant-experienced mothers were endowed with higher baseline levels of antioxidants, which conferred an enhanced capacity to minimize oxidative damage to lipids, proteins and DNA when exposed to AN8 fuel. This pattern was strongest following exposure to 900ppm AN8, where lipid and protein damage was 5-7 times greater than baseline levels in contaminant-naïve female embryos in comparison to 3-4 times greater in contaminant-experienced female embryos. Despite this inherited resilience against oxidative stress, abnormal development was as high in these embryos when exposed to AN8 as in those derived from contaminant-naïve mothers (up to 80% abnormality), implying the conferred advantage may not translate to a fitness or survival gain, at least up to the blastulae stage. Our findings document the first evidence for parent-to-offspring transfer of oxidative stress resilience in an Antarctic marine invertebrate.

Matrix metalloproteinases in a sea urchin ligament with adaptable mechanical properties.

Mutable collagenous tissues (MCTs) of echinoderms show reversible changes in tensile properties (mutability) that are initiated and modulated by the nervous system via the activities of cells known as juxtaligamental cells. The molecular mechanism underpinning this mechanical adaptability has still to be elucidated. Adaptable connective tissues are also present in mammals, most notably in the uterine cervix, in which changes in stiffness result partly from changes in the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). There have been no attempts to assess the potential involvement of MMPs in the echinoderm mutability phenomenon, apart from studies dealing with a process whose relationship to the latter is uncertain. In this investigation we used the compass depressor ligaments (CDLs) of the sea-urchin Paracentrotus lividus. The effect of a synthetic MMP inhibitor - galardin - on the biomechanical properties of CDLs in different mechanical states ("standard", "compliant" and "stiff") was evaluated by dynamic mechanical analysis, and the presence of MMPs in normal and galardin-treated CDLs was determined semi-quantitatively by gelatin zymography. Galardin reversibly increased the stiffness and storage modulus of CDLs in all three states, although its effect was significantly lower in stiff than in standard or compliant CDLs. Gelatin zymography revealed a progressive increase in total gelatinolytic activity between the compliant, standard and stiff states, which was possibly due primarily to higher molecular weight components resulting from the inhibition and degradation of MMPs. Galardin caused no change in the gelatinolytic activity of stiff CDLs, a pronounced and statistically significant reduction in that of standard CDLs, and a pronounced, but not statistically significant, reduction in that of compliant CDLs. Our results provide evidence that MMPs may contribute to the variable tensility of the CDLs, in the light of which we provide an updated hypothesis for the regulatory mechanism controlling MCT mutability.

The protease degrading sperm histones post-fertilization in sea urchin eggs is a nuclear cathepsin L that is further required for embryo development.

Proteolysis of sperm histones in the sea urchin male pronucleus is the consequence of the activation at fertilization of a maternal cysteine protease. We previously showed that this protein is required for male chromatin remodelling and for cell-cycle progression in the newly formed embryos. This enzyme is present in the nucleus of unfertilized eggs and is rapidly recruited to the male pronucleus after insemination. Interestingly, this cysteine-protease remains co-localized with chromatin during S phase of the first cell cycle, migrates to the mitotic spindle in M-phase and is re-located to the nuclei of daughter cells after cytokinesis. Here we identified the protease encoding cDNA and found a high sequence identity to cathepsin proteases of various organisms. A phylogenetical analysis clearly demonstrates that this sperm histone protease (SpHp) belongs to the cathepsin L sub-type. After an initial phase of ubiquitous expression throughout cleavage stages, SpHp gene transcripts become restricted to endomesodermic territories during the blastula stage. The transcripts are localized in the invaginating endoderm during gastrulation and a gut specific pattern continues through the prism and early pluteus stages. In addition, a concomitant expression of SpHp transcripts is detected in cells of the skeletogenic lineage and in accordance a pharmacological disruption of SpHp activity prevents growth of skeletal rods. These results further document the role of this nuclear cathepsin L during development.

Expression pattern of polyketide synthase-2 during sea urchin development.

Polyketide synthases (PKSs) are a large group of proteins responsible for the biosynthesis of polyketide compounds, which are mainly found in bacteria, fungi, and plants. Polyketides have a wide array of biological functions, including antibiotic, antifungal, predator defense, and light responses. In this study, we describe the developmental expression pattern of pks2, one of two pks found in the sea urchin genome. Throughout development, pks2 expression was restricted to skeletogenic cells and their precursors. Pks2 was first detected during the blastula stage. The transcript level peaked at hatched blastula, when all skeletogenic cell precursors expressed pks2. This was followed by a steady decline in expression in the skeletogenic cells on the aboral side of the embryo. By the prism stage, pks2 expression was limited to only 3-4 skeletogenic cells localized on the oral side.

Estudos toxinológicos do ouriço-do-mar Echinometra lucunter / Toxinologic studies about Echinometra lucunter sea urchin

Echinometra lucunter (Linnaeus, 1758) e o ourico do mar mais conhecido da costa brasileira, responsavel por cerca de 50% dos acidentes com animais marinhos. A injuria inicial causada pelos ouricos e a penetracao dos espinhos na pele, seguida da retencao de seus fragmentos. Esses fragmentos causam reacoes inflamatorias, dor local, e ocasionalmente doenca sistemica,sintomas que eram atribuidos somente ao trauma mecanico. Acidentes apos a ingestao de ovas tambem ja foram descritos. O objetivo deste trabalho foi verificar a presenca de toxinas nos espinhos e no liquido celomico perivisceral do ourico do mar E. lucunter do litoral de São Paulo, isolar e caracterizar essas moleculas e avaliar a correlacao histologica entre as toxinas presentes e uma possivel estrutura sectora... .

Echinometra lucunter (Linnaeus, 1758) is the most spread the sea urchin of the Brazilian shore line and its responsible for circa 50% of all marine animals acidents. Initial sea urchin injury is caused by the spine penetration, followed by its fragmentation under the skin. This fragments can cause local pain and inflammatory reactions, initially atributed to the mechanical trauma of the spines penetration, and ocasionally systemic disorders. Few accidents were reported after the ingestion of raw sea urchin. The aim of this work was to asses the presence of toxins in the spines and perivisceral celomic fluid of E. lucunter sea urchun from São Paulo shore line, through the biological driven isolation and biochemical characterization of the toxins... .

Functional insights into the activation mechanism of Ste20-related kinases.

Mammalian Ste20-related kinases modulate salt transport and ion homeostasis through physical interaction and phosphorylation of cation-chloride cotransporters. Identification of a sea urchin (Strongylocentrotus purpuratus) ortholog of the mouse Oxidative Stress Response 1 (OSR1) kinase prompted the cloning and testing of the functional effect of a non-mammalian kinase on a mammalian cotransporter. Heterologous expression of sea urchin OSR1 (suOSR1) cRNA with mouse WNK4 cRNA and mouse NKCC1 cRNA in Xenopus laevisoocytes activated the cotransporter indicating evolutionary conservation of the WNK4-OSR1-NKCC signaling pathway. However, expression of a suOSR1 kinase mutated to confer constitutive activity did not result in stimulation of the cotransporter. Using a chimeric strategy, we determined that both the mutated catalytic and regulatory domains of the suOSR1 kinase were functional, suggesting that the tertiary structure of full-length mutated suOSR1 must somehow adopt an inactive conformation. In order to identify the regions or residues which lock the suOSR1 kinase in an inactive conformation, we created and tested several additional chimeras by replacing specific portions of the suOSR1 gene with complimentary mouse OSR1 sequences. Co-expression of these chimeras identified several regions in both the catalytic and regulatory domain of suOSR1 which possibly prevented the kinase from acquiring an active conformation. Interestingly, non-functional suOSR1 chimeras were able to activate mouse NKCC1 when a mouse scaffolding protein, Cab39, was co-expressed in frog oocytes. Sea urchin/mouse OSR1 chimeras and kinase stabilization with mouse Cab39 has provided some novel insights into the activation mechanism of the Ste20-related kinases.

The evolution of nervous system patterning: insights from sea urchin development.

Recent studies of the sea urchin embryo have elucidated the mechanisms that localize and pattern its nervous system. These studies have revealed the presence of two overlapping regions of neurogenic potential at the beginning of embryogenesis, each of which becomes progressively restricted by separate, yet linked, signals, including Wnt and subsequently Nodal and BMP. These signals act to specify and localize the embryonic neural fields - the anterior neuroectoderm and the more posterior ciliary band neuroectoderm - during development. Here, we review these conserved nervous system patterning signals and consider how the relationships between them might have changed during deuterostome evolution.

11Beta-hydroxysteroid dehydrogenase-type 2 evolved from an ancestral 17beta-hydroxysteroid dehydrogenase-type 2.

11Beta-hydroxysteroid dehydrogenase-type 2 (11beta-HSD2) regulates the local concentration of cortisol that can activate the glucocorticoid receptor and mineralocorticoid receptor, as well as the concentration of 11-keto-testosterone, the active androgen in fish. Similarly, 17beta-HSD2 regulates the levels of testosterone and estradiol that activate the androgen receptor and estrogen receptor, respectively. Interestingly, although human 11beta-HSD2 and 17beta-HSD2 act at different positions on different steroids, these enzymes are paralogs. Despite the physiological importance of 11beta-HSD2 and 17beta-HSD2, details of their origins and divergence from a common ancestor are not known. An opportunity to understand their evolution is presented by the recent sequencing of genomes from sea urchin, a basal deuterostome, and amphioxus, a basal chordate, and the availability of substantial sequence for acorn worm and elephant shark, which together provide a more complete dataset for analysis of the origins of 11beta-HSD2 and 17beta-HSD2. BLAST searches find an ancestral sequence of 17beta-HSD2 in sea urchin, acorn worm and amphioxus, while an ancestral sequence of 11beta-HSD2 first appears in sharks. Sequence analyses indicate that 17beta-HSD2 in sea urchin may have a non-enzymatic activity. Evolutionary analyses indicate that if acorn worm 17beta-HSD2 is catalytically active, then it metabolizes novel substrate(s).

Use of specific glycosidases to probe cellular interactions in the sea urchin embryo.

We present an unusual and novel model for initial investigations of a putative role for specifically conformed glycans in cellular interactions. We have used alpha- and ss-amylase and alpha- and ss-glucosidase in dose-response experiments evaluating their effects on archenteron organization using the NIH designated sea urchin embryo model. In quantitative dose-response experiments, we show that defined activity levels of alpha-glucosidase and ss-amylase inhibited archenteron organization in living Lytechinus pictus gastrula embryos, whereas all concentrations of ss-glucosidase and alpha-amylase were without substantial effects on development. Product inhibition studies suggested that the enzymes were acting by their specific glycosidase activities and polyacrylamide gel electrophoresis suggested that there was no detectable protease contamination in the active enzyme samples. The results provide evidence for a role of glycans in sea urchin embryo cellular interactions with special reference to the possible structural conformation of these glycans based on the differential activities of the alpha- and ss-glycosidases.

A new nuclear protease with cathepsin L properties is present in HeLa and Caco-2 cells.

Recently many authors have reported that cathepsin L can be found in the nucleus of mammalian cells with important functions in cell-cycle progression. In previous research, we have demonstrated that a cysteine protease (SpH-protease) participates in male chromatin remodeling and in cell-cycle progression in sea urchins embryos. The gene that encodes this protease was cloned. It presents a high identity sequence with cathepsin L family. The active form associated to chromatin has a molecular weight of 60 kDa, which is higher than the active form of cathepsin L described until now, which range between 25 and 35 kDa. Another difference is that the zymogen present in sea urchin has a molecular weight of 75 and 90 kDa whereas for human procathepsin L has a molecular weight of 38-42 kDa. Based on these results and using a polyclonal antibody available in our laboratory that recognizes the active form of the 60 kDa nuclear cysteine protease of sea urchin, ortholog to human cathepsin L, we investigated the presence of this enzyme in HeLa and Caco-2 cells. We have identified a new nuclear protease, type cathepsin L, with a molecular size of 60 kDa, whose cathepsin activity increases after a partial purification by FPLC and degrade in vitro histone H1. This protease associates to the mitotic spindle during mitosis, remains in the nuclei in binuclear cells and also translocates to the cytoplasm in non-proliferative cells.

Sea urchin arylsulfatase, an extracellular matrix component, is involved in gastrulation during embryogenesis.

Arylsulfatases (Arses) have been regarded as lysosomal enzymes because of their hydrolytic activities on synthetic aromatic substrates and their lysosomal localization of their enzymatic activities. Using sea urchin embryos, we previously demonstrated that the bulk of Hemicentrotus Ars (HpArs) does not exhibit enzyme activity and is located on the apical surface of the epithelial cells co-localizing with sulfated polysaccharides. Here we show that HpArs strongly binds to sulfated polysaccharides and that repression of the synthesis by HpArs-morpholino results in retardation of gastrulation in the sea urchin embryo. Accumulation of HpArs protein and sulfated polysaccharides on the apical surface of the epithelial cells in sea urchin larvae is repressed by treatment with beta-aminopropionitrile (BAPN), suggesting that deposition of HpArs and sulfated polysaccharides is dependent on the crosslinking of proteins such as collagen-like molecules. We suggest that HpArs functions by binding to components of the extracellular matrix.