Project description:Well-annotated and contiguous genomes are an indispensable resource for understanding the evolution, development, and metabolic capacities of organisms. Sponges, an ecologically important non-bilaterian group of primarily filter-feeding sessile aquatic organisms, are underrepresented with respect to available genomic resources. Here we provide a high-quality and well-annotated genome of Aphrocallistes vastus, a glass sponge (Porifera: Hexactinellida) that forms large reef structures off the coast of British Columbia (Canada). We show that its genome is approximately 80 Mb, small compared to most other metazoans, and contains nearly 2500 nested genes, more than other genomes. Hexactinellida is characterized by a unique skeletal architecture made of amorphous silicon dioxide (SiO2), and we identified 419 differentially expressed genes between the osculum, i.e. the vertical growth zone of the sponge, and the main body. Among the upregulated ones, mineralization-related genes such as glassin, as well as collagens and actins, dominate the expression profile during growth. Silicateins, suggested being involved in silica mineralization, especially in demosponges, were not found at all in the A. vastus genome and suggests that the underlying mechanisms of SiO2 deposition in the Silicea sensu stricto (Hexactinellida + Demospongiae) may not be homologous.
Project description:The glass sponge Aphrocallistes vastus contributes to the formation of large reefs unique to the Northeast Pacific Ocean. These habitats have tremendous filtration capacity that facilitates flow of carbon between trophic levels. Their sensitivity and resilience to climate change, and thus persistence in the Anthropocene, is unknown. Here we show that ocean acidification and warming, alone and in combination have significant adverse effects on pumping capacity, contribute to irreversible tissue withdrawal, and weaken skeletal strength and stiffness of A. vastus. Within one month sponges exposed to warming (including combined treatment) ceased pumping (50-60%) and exhibited tissue withdrawal (10-25%). Thermal and acidification stress significantly reduced skeletal stiffness, and warming weakened it, potentially curtailing reef formation. Environmental data suggests conditions causing irreversible damage are possible in the field at +0.5?°C above current conditions, indicating that ongoing climate change is a serious and immediate threat to A. vastus, reef dependent communities, and potentially other glass sponges.
Project description:BackgroundMitochondrial genomes (mtDNA) of numerous sponges have been sequenced as part of an ongoing effort to resolve the class-level phylogeny of the Porifera, as well as to place the various lower metazoan groups on the animal-kingdom tree. Most recently, the partial mtDNA of two glass sponges, class Hexactinellida, were reported. While previous phylogenetic estimations based on these data remain uncertain due to insufficient taxon sampling and accelerated rates of evolution, the mtDNA molecules themselves reveal interesting traits that may be unique to hexactinellids. Here we determined the first complete mitochondrial genome of a hexactinellid sponge, Aphrocallistes vastus, and compared it to published poriferan mtDNAs to further describe characteristics specific to hexactinellid and other sponge mitochondrial genomes.ResultsThe A. vastus mtDNA consisted of a 17,427 base pair circular molecule containing thirteen protein-coding genes, divergent large and small subunit ribosomal RNAs, and a reduced set of 18 tRNAs. The A. vastus mtDNA showed a typical hexactinellid nucleotide composition and shared a large synteny with the other sequenced glass sponge mtDNAs. It also contained an unidentified open reading frame and large intergenic space region. Two frameshifts, in the cox3 and nad6 genes, were not corrected by RNA editing, but rather possessed identical shift sites marked by the extremely rare tryptophan codon (UGG) followed by the common glycine codon (GGA) in the +1 frame.ConclusionHexactinellid mtDNAs have shown similar trends in gene content, nucleotide composition, and codon usage, and have retained a large gene syntenty. Analysis of the mtDNA of A. vastus has provided evidence diagnostic for +1 programmed translational frameshifting, a phenomenon disparately reported throughout the animal kingdom, but present in the hexactinellid mtDNAs that have been sequenced to date.
Project description:Lectins display a variety of biological functions including insecticidal, antimicrobial, as well as antitumor activities. In this report, a gene encoding Aphrocallistes vastus lectin (AVL), a C-type lectin, was inserted into an oncolytic vaccinia virus vector (oncoVV) to form a recombinant virus oncoVV-AVL, which showed significant in vitro antiproliferative activity in a variety of cancer cell lines. Further investigations revealed that oncoVV-AVL replicated faster than oncoVV significantly in cancer cells. Intracellular signaling elements including NF-κB2, NIK, as well as ERK were determined to be altered by oncoVV-AVL. Virus replication upregulated by AVL was completely dependent on ERK activity. Furthermore, in vivo studies showed that oncoVV-AVL elicited significant antitumor effect in colorectal cancer and liver cancer mouse models. Our study might provide insights into a novel way of the utilization of marine lectin AVL in oncolytic viral therapies.