科研之友
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摘要
Background: Adhesion mediated through the integrin family of cell surface receptors is central to early development throughout the Metazoa, playing key roles in cell-extra cellular matrix adhesion and modulation of cadherin activity during the convergence and extension movements of gastrulation. It has been suggested that Caenorhabditis elegans, which has a single beta and two alpha integrins, might reflect the ancestral integrin complement. Investigation of the integrin repertoire of anthozoan cnidarians such as the coral Acropora millepora is required to test this hypothesis and may provide insights into the original roles of these molecules.
Results: Two novel integrins were identified in Acropora. AmItg alpha 1 shows features characteristic of a integrins lacking an I-domain, but phylogenetic analysis gives no clear indication of its likely binding specificity. AmItg beta 2 lacks consensus cysteine residues at positions 8 and 9, but is otherwise a typical beta integrin. In situ hybridization revealed that AmItg alpha 1, AmItg beta 1, and AmItg beta 2 are expressed in the presumptive endoderm during gastrulation. A second anthozoan, the sea anemone Nematostella vectensis, has at least four beta integrins, two resembling AmItg beta 1 and two like AmItg beta 2, and at least three a integrins, based on its genomic sequence.
Conclusion: In two respects, the cnidarian data do not fit expectations. First, the cnidarian integrin repertoire is more complex than predicted: at least two beta s in Acropora, and at least three as and four beta s in Nematostella. Second, whereas the bilaterian alpha s resolve into well-supported groups corresponding to those specific for RGD-containing or laminin-type ligands, the known cnidarian as are distinct from these. During early development in Acropora, the expression patterns of the three known integrins parallel those of amphibian and echinoderm integrins.
- 出版日期2008-5-9
