過重力環境がウニの骨片形成に与える影響

摘要

In sea urchin embryo, the skeletogenic cells are called primary meshenchymen cells derived from micromeres at 16-cell stage. We reported a promotive effect of hypergravity in the low serum concentration culture of the skeletogenic cells. In this condition, cultured skeletogenic cells were so sensitive that they showed a clear difference of skeletogenesis also for the different substrate of culture plate. The decrease of spicule number by the inhibitor of Ca~(2+)-channel is recovered under hypergravity condition. The culture in low Ca~(2+) concentration also decreased the number of formed spicule and the number was recovered under hypergravity, too. These results show the possibility that the Ca~(2+) uptake is one of a candidate process that is affected by hypergravity condition.The spicule also contains spicule matrix proteins. The expression of their mRNA under hypergravity was examined and the level was not different from control condition.%ウニ胚の単離小割球による骨片形成の培養系では、石灰化を担う細胞を純粋に培養することができる。このため、生物石灰化における形態形成のモデル系として重力環境の影響を評価する際に、他の組織の影響を考慮する必要がない。これまでに、過重力環境により形成される骨片の数が増加することや、骨片形成に関わる過程の中でCa~（2+）の取り込みに過重力が影響している可能性を報告した（Imai et al,2006）。今回は、細胞の培養条件によって影響される骨片形勢の比較から過重力の影響を考察した。さらに、骨片基質タンパク質の発現に対す過重力の影響についても調べた。