Sirotkin V, Seipel S, Krendel M, Bonder E M
Program in Cellular and Molecular Biodynamics, Department of Biological Sciences, Rutgers University, Newark, New Jersey 07102, USA.
Mol Reprod Dev. 2000 Oct;57(2):111-26. doi: 10.1002/1098-2795(200010)57:2<111::AID-MRD2>3.0.CO;2-T.
Early sea urchin development requires a dynamic reorganization of both the actin cytoskeleton and cytoskeletal interactions with cellular membranes. These events may involve the activities of multiple members of the superfamily of myosin motor proteins. Using RT-PCR with degenerate myosin primers, we identified 11 myosin mRNAs expressed in unfertilized eggs and coelomocytes of the sea urchin Strongylocentrotus purpuratus. Seven of these sea urchin myosins belonged to myosin classes Igamma, II, V, VI, VII, IX, and amoeboid-type I, and the remaining four may be from novel classes. Sea urchin myosins-V, -VI, -VII, and amoeboid-type-I were either completely or partially cloned and their molecular structures characterized. Sea urchin myosins-V, -VI, -VII, and amoeboid-type-I shared a high degree of sequence identity with their respective family members from vertebrates and they retained their class-specific structure and domain organization. Analysis of expression of myosin-V, -VI, -VII, and amoeboid-type-I mRNAs during development revealed that each myosin mRNA displayed a distinct temporal pattern of expression, suggesting that myosins might be involved in specific events of early embryogenesis. Interestingly, the onset of gastrulation appeared to be a pivotal point in modulation of myosin mRNA expression. The presence of multiple myosin mRNAs in eggs and embryos provides insight into the potential involvement of multiple specific motor proteins in the actin-dependent events of embryo development.
海胆的早期发育需要肌动蛋白细胞骨架以及细胞骨架与细胞膜之间相互作用的动态重组。这些事件可能涉及肌球蛋白运动蛋白超家族多个成员的活动。我们使用简并性肌球蛋白引物进行逆转录聚合酶链反应（RT-PCR），在紫海胆未受精卵和体腔细胞中鉴定出11种肌球蛋白mRNA。其中七种海胆肌球蛋白属于肌球蛋白Iγ、II、V、VI、VII、IX类以及变形虫I型，其余四种可能属于新的类别。海胆肌球蛋白V、VI、VII和变形虫I型被全部或部分克隆，并对其分子结构进行了表征。海胆肌球蛋白V、VI、VII和变形虫I型与其脊椎动物的相应家族成员具有高度的序列同一性，并且保留了其类别特异性结构和结构域组织。对肌球蛋白V、VI、VII和变形虫I型mRNA在发育过程中的表达分析表明，每种肌球蛋白mRNA都呈现出独特的时间表达模式，这表明肌球蛋白可能参与早期胚胎发生的特定事件。有趣的是，原肠胚形成的开始似乎是调节肌球蛋白mRNA表达的一个关键点。卵子和胚胎中存在多种肌球蛋白mRNA，这为多种特定运动蛋白可能参与胚胎发育中依赖肌动蛋白的事件提供了线索。
