Exogenous hyalin and sea urchin gastrulation, part III: biological activity of hyalin extracted from lytechinus pictus embryos

摘要

Hyalin is a large glycoprotein, consisting of the hyalin repeat domain and non-repeated regions, andudis the major component of the hyaline layer in the early sea urchin embryo of Strongylocentrotusudpurpuratus. The hyalin repeat domain has been identified in proteins from organisms as diverse asudbacteria, sea urchins, worms, flies, mice and humans. While the specific function of hyalin and theudhyalin repeat domain is incompletely understood, many studies suggest that it has a functional roleudin adhesive interactions. In part I of this series, we showed that hyalin isolated from the sea urchinudS. purpuratus blocked archenteron elongation and attachment to the blastocoel roof occurring duringudgastrulation in S. purpuratus embryos, (Razinia et al., 2007). The cellular interactions that occur inudthe sea urchin, recognized by the U.S. National Institutes of Health as a model system, may provideudinsights into adhesive interactions that occur in human health and disease. In part II of this series,udwe showed that S. purpuratus hyalin heterospecifically blocked archenteron-ectoderm interaction inudLytechinus pictus embryos (Alvarez et al, 2007). In the current study, we have isolated hyalin fromudthe sea urchin L. pictus and demonstrated that L. pictus hyalin homospecifically blocks archenteronectodermudinteraction, suggesting a general role for this glycoprotein in mediating a specific set ofudadhesive interactions. We also found one major difference in hyalin activity in the two sea urchinudspecies involving hyalin influence on gastrulation invagination.