Hydra, first described by Anton van Leeuwenhoek in a letter to the Royal Society in 1702, has been studied by biologists for centuries and now is an important model for work on axial patterning, stem cell biology and regeneration. Its genome, over half of which is made up of mobile elements, has now been sequenced, as has the genome of a Curvibacter sp. bacterium stably associated with Hydra magnipapillata. Comparisons of the Hydra genome with those of other animals provide insights into the evolution of epithelia, contractile tissues, developmentally regulated transcription factors, pluripotency genes and the neuromuscular junction, as well as the Spemann–Mangold organizer, the region in the early embryo that establishes the embryo's axis. The freshwater cnidarian Hydra is a significant model for studies of axial patterning, stem cell biology and regeneration. Its (A+T)-rich genome has now been sequenced. Comparison of this genome with those of other animals provides insights into the evolution of epithelia, contractile tissues, developmentally regulated transcription factors, pluripotency genes and more. The freshwater cnidarian Hydra was first described in 17021 and has been the object of study for 300 years. Experimental studies of Hydra between 1736 and 1744 culminated in the discovery of asexual reproduction of an animal by budding, the first description of regeneration in an animal, and successful transplantation of tissue between animals2. Today, Hydra is an important model for studies of axial patterning3, stem cell biology4 and regeneration5. Here we report the genome of Hydra magnipapillata and compare it to the genomes of the anthozoan Nematostella vectensis6 and other animals. The Hydra genome has been shaped by bursts of transposable element expansion, horizontal gene transfer, trans-splicing, and simplification of gene structure and gene content that parallel simplification of the Hydra life cycle. We also report the sequence of the genome of a novel bacterium stably associated with H. magnipapillata. Comparisons of the Hydra genome to the genomes of other animals shed light on the evolution of epithelia, contractile tissues, developmentally regulated transcription factors, the Spemann–Mangold organizer, pluripotency genes and the neuromuscular junction.

Signal transduction in response to interleukin‐6 (IL‐6) requires binding of the cytokine to its receptor (IL‐6R) and subsequent homodimerization of the signal transducer gp130. The complex of IL‐6 and soluble IL‐6R (sIL‐6R) triggers dimerization of gp130 and induces responses on cells that do not express membrane bound IL‐6R. Naturally occurring soluble gp130 (sgp130) can be found in a ternary complex with IL‐6 and sIL‐6R. We created recombinant sgp130 proteins that showed binding to IL‐6 in complex with sIL‐6R and inhibited IL‐6/sIL‐6R induced proliferation of BAF/3 cells expressing gp130. Surprisingly, sgp130 proteins did not affect IL‐6 stimulated proliferation of BAF/3 cells expressing gp130 and membrane bound IL‐6R, indicating that sgp130 did not interfere with IL‐6 bound to IL‐6R on the cell surface. Additionally, sgp130 partially inhibited proliferation induced by leukemia inhibitory factor (LIF) and oncostatin M (OSM) albeit at higher concentrations. Recombinant sgp130 protein could be used to block the anti‐apoptotic effect of sIL‐6R on lamina propria cells from Crohn disease patients. We conclude that sgp130 is the natural inhibitor of IL‐6 responses dependent on sIL‐6R. Furthermore, recombinant sgp130 is expected to be a valuable therapeutic tool to specifically block disease states in which sIL‐6R transsignaling responses exist, e.g. in morbus Crohn disease.

We present a perspective on the molecular evolution of the extracellular matrix (ECM) in metazoa that draws on research publications and data from sequenced genomes and expressed sequence tag libraries. ECM components do not function in isolation, and the biological ECM system or “adhesome” also depends on posttranslational processing enzymes, cell surface receptors, and extracellular proteases. We focus principally on the adhesome of internal tissues and discuss its origins at the dawn of the metazoa and the expansion of complexity that occurred in the chordate lineage. The analyses demonstrate very high conservation of a core adhesome that apparently evolved in a major wave of innovation in conjunction with the origin of metazoa. Integrin, CD36, and certain domains predate the metazoa, and some ECM-related proteins are identified in choanoflagellates as predicted sequences. Modern deuterostomes and vertebrates have many novelties and elaborations of ECM as a result of domain shuffling, domain innovations and gene family expansions. Knowledge of the evolution of metazoan ECM is important for understanding how it is built as a system, its roles in normal tissues and disease processes, and has relevance for tissue engineering, the development of artificial organs, and the goals of synthetic biology.

Glycosaminoglycans, a major component of the extracellular matrix molecules in animal tissues, play important roles in various physiological events. Glycosaminoglycans are found in not only vertebr...